TABLE OF CONTENTS: ASTRONOMY PAGE 1 BIOLOGY: ANIMALS 4 BIOLOGY: PLANTS 8 CHEMISTRY 11 ENVIRONMENTAL STUDIES 15 GENETICS 19 GEOLOGY 21 HUMAN BODY: DISEASE 23 HUMAN BODY: NUTRITION 25 HUMAN BODY: SYSTEMS 27 MEASUREMENT 29 METEOROLOGY 31 OCEANOGRAPHY 35 PALEONTOLOGY 37 PHYSICS 41 PSYCHOLOGY 46 TECHNOLGOY 48 ASTRONOMY What is the difference between a One main difference is that a planet orbits a star. The other main difference is that planet and a star? stars produce light and heat because nuclear reactions occur within the stars. Planets do not produce light or heat themselves. They are visible to us because they reflect light. The sun is the star in our solar system, and its light shines on the 9 planets, including earth, that orbit it. Because planets do not make their own light, we can see only planets that are relatively close to us. We can see many stars in the sky, but none of the possibly millions of planets that orbit them. An astronomical unit is 93 Megaparsecs are useful for measuring distances beyond our galaxy, the Milky million miles, the distance to the Way. The Milky Way contains the sun and sun. A light-year is 6 trillion the 9 planets in our solar system and miles, and a megaparsec is more millions of other solar systems. There are many galaxies beyond the Milky Way. than 3 million light-years, What might an astronomer measure in megaparsecs? How can looking at stars help Because it takes time for light to travel, an astronomer looking at the stars is actually astronomers estimate the age of looking into the past. The most powerful the universe? telescopes detect galaxies at least 10 billion light-years away. This means that the universe must be at least 10 billion years old, since that is how long ago light began Traveling to us from those galaxies, Most astronomers estimate that the universe is 15 to 20 billion years old. Do you think that other Some astronomers believe that there are other universes, although no one has been universes exist? Explain. able to prove this. One reason for this belief is that it seems possible that the circumstances that created our universe could have occurred more than once. Other astronomers argue that the universe is so vast that it is actually part of a larger entity. In addition, some physicists argue that there are other universes that are very, very small. Why do astronomers rarely use Astronomers do not measure these distances in miles or kilometers because miles or kilometers when the numbers would be too big. Distances in measuring distances in space? space are measured in light-years. A light- year is the distance light travels in a year. Since light travels at a speed of 186,282 miles per second, a light-year is equal to 5,879 billion miles, or almost 6 trillion miles. If you were traveling at 588 miles per hour, about as fast as an airplane flies, it would take you over 10 billion years to travel 1 light-year. A billion is a very large number. One billion seconds is almost 32 years. Many scientists believe that the Answers will vary but may include the following: If this debris came from earth, it moon was formed from dust and may have orbited earth as rings for many debris either from earth or from years until gravity pulled the particles somewhere else in the solar together to form the moon. Other hypotheses are that the earth and moon system. Form a hypothesis to formed separately in about the same place, explain how this debris became or that a blob of matter flew off from the the moon. earth as it was forming, or that the moon formed elsewhere in the solar system and was captured by earth’s gravitational pull. Most scientists believe that, as the earth and other planets were forming, the solar system was filled with particles of debris. Do you think there is litter in A great variety of litter is in outer space. It outer space? Explain. is made up of parts of spaceships. For example, by 1989, 12 orbiters and 23 landers had been sent to Mercury, Venus and Mars alone. There are 35 loose rocket stages from these same launches drifting in orbit between Venus and Mars, while the landers are sitting somewhere, either smashed or intact. No one knows the location of six spacecraft that headed for the Moon but missed, a rocket nose cone that didn’t reach Mars, or nearly 2000 probes and satellites that entered space but never came back. After astronauts first saw earth Earthshine is the light visible in outer space that comes from this planet. Just as we can from outer space, they talked see moonshine on earth, someone in a about something they called spaceship on the moon or on a nearby earthshine. What is earthshine? planet can see earthshine. Earthshine is light reflected from the sun. A nebula is a cloud of particles A nebula is the birthplace—and can be the dying place—of stars. Underneath the between stars. Explain the many layers of dust and gas particles in a following statement: A nebula is nebula are especially dense clumps, or the birthplace of stars. globules, of dust and gas. These globules are the beginnings of star, which are not yet hot enough or large enough to shine. A nebula can also form during the death of a star. As a star ages, it may emit gases into space. Those gases form a ring that is called a planetary nebula because it circles the dying star in an orbit like planets. Why was it so challenging for Hitting the target, the moon in this case, might be compared to making a hole-in- scientists to land a spacecraft on one in golf. Like a golf ball, the space the moon? vehicle had to travel a great distance with great force and accuracy. It also had to set down at just the right moment and with just the right amount of force into a declivity on the moon’s surface. Proof of the difficulty of landing on the moon can be found on the moon’s surface, which is littered with wrecks and pitted from crashes. According to some scientists, Telescopes cannot see light from the big bang because, even 300,000 years after this the universe began as the result explosion, the universe was still so dense of an explosion—called the big that it was completely opaque. This means that no light could pass through the bang—more than 10 billion universe. years ago. The universe then was very dense and much smaller than it is now. Why can’t powerful telescopes see light from the big bang? BIOLOGY: ANIMALS What adaptations did Amphibians developed stronger fins and muscles to support the weight of their amphibians make in order to bodies. After millions of years, bones evolve from water animals to appeared in these fins, and the fins evolved land animals? into feet. Amphibians also developed lungs, which allowed them to get oxygen from the air instead of from the water. The first true amphibian was Ichthyostega, a fishlike creature with small stubby legs. Why do snakes have forked Snakes smell with their tongues. As a snake hunts for prey, it flicks its tongue tongues? along the ground and then pulls it back into its mouth. A forked tongue covers a wider area. A hollow tube in the snake’s mouth is lined with sensitive cells like taste buds that help the snake scent and track its prey. What do your head and the shell The shell of a turtle is made of a layer of bone covered with keratin, the same of a turtle have in common? protein that makes up your hair and nails. The shell consists of separate plates linked with the same kind of jagged joint that links the plates of your skull together. As humans age, their faces get Some animals, such as whales, elephants, crocodiles, and fish, grow throughout their wrinkled, and their hair thins or lives. These animals show their age by turns gray. How does an their increased size. Male deer, elk, and animal’s appearance change as it moose grow bigger and bigger antlers as they age. When they are very old, their grows older? antlers start to shrink. Some types of fish and reptiles have growth rings on their scales, just as trees have rings. A pheromone is a chemical By detecting the female’s pheromone, the male moth can find a mate. The males produced by an animal for detect the pheromone with the feathery attracting others of its species. parts of their antennae. A male can tell by a female’s particular scent if she is of his How do you think moths locate species. their mates? Which of the following abilities The abilities to convey complex ideas and to make complex tools set humans apart set humans apart from other from other animals. Although some other animals? The ability to animals have a kind of language, none has Form communities the vocabulary or speech ability humans have. And while some other animals use Teach their young tools, none are as complex as those made Convey complex ideas by humans. Make complex tools Some animals can choose A species might have a limited population and require more males and females at a whether they or their offspring particular time. For example, bee will be male or female. How populations are predominantly female. The might this ability benefit a queen bee can produce males by not fertilizing some of the eggs she lays. species? Alligators, too can control the gender mix in their populations. Alligator eggs incubated at higher temperatures develop into males; those incubated at lower temperatures develop into females. The ability to choose the gender of the offspring helps a species to control its population in response to the available resources in the environment. An ecosystem consists of a com- Answers will vary but may include, ―If a newcomer to an ecosystem has no effective munity of living things and their competitors than it will survive.‖ For environment. A newcomer to an instance, the house sparrow often secures a ecosystem, as he house sparrow next by invading other birds’ nests, killing any eggs it finds, and driving off the was when it came to North inhabitants. The birds in the existing North America 150 years ago, can American ecosystem had developed no sometimes be very successful. defense against the sparrow’s attack. At times, however, a predator’s success can be Why might this be true? its disadvantage. For example, if a species of hawk habitually hunts a species of squirrel and kills to many, the hawks’ entire food supply will diminish. Then the hawk population will decrease. Do fish need water as a nutrient? Like people, saltwater fish need water in order to keep from drying out. However, If so, do ocean fish get nutrients fish do not drink water. Instead, it passes in by drinking the salty water that and out of their cells through a process surrounds them? called osmosis. Special cells, together with the process of digestion, help the fish’s body get rid of the salt. Some kinds of fish can change Some coral reef fish, such as clownfish, begin as males and becomes females. their gender from male to Clownfish live within the tentacles of a sea female. How might this ability anemone, which protects them. Because aid the fish? they have a very small territory, their ability to change gender makes sense. If the egg-laying female is killed, a male can take her place by changing into a female. Other kinds of reef fish can change from female to make, which is more common. Incidentally all human fetuses are anatomically female early in their development. As they grown inside their mothers, the genetically male fetuses become anatomically male. How are tiny ants able to carry In a small body, a skeletal structure like the ant’s gives it much strength relative to its loads many times heavier than size. Like other insects, an ant has its they are? skeleton on the outside of its body. This strong suit of armor can support weight much greater than that of the ant’s body. Its muscles are between the plates, or shells, of it skeleton. The advantages of this system disappear with size, however. A 150-lb.ant would be much weaker than a 150-lb.person. Its suit of armor would be so heavy that the ant would collapse from its own weight. Why do ants gather on The question has several possible answers. (1) Some ants like to nest under rocks and sidewalks? other hard surfaces. (2) People often drop food on sidewalks, and the food attracts ants. (3) Ants use chemical signals to attract one another, and their chemical trails are easily detected by other ants on sidewalks. (4) Sidewalks absorb heat from the sun, and ants like the warmth. (5) Ants are everywhere. They’re just easier to see on sidewalks. Can you name something that is Viruses consist of packages of protein surrounding genetic material that is neither neither living nor nonliving? living nor nonliving. The characteristics of living things include the ability to grow and to reproduce. Plants and animals do both of these things. Rocks, chemicals, and minerals do not. Viruses do not grow, but they can reproduce by using cells in the bodies of human beings or other creatures to make copies of themselves. When a virus infects cells in you nose or throat, we can say it becomes alive. When viruses are taken out of contact with living cells, however, they are lifeless chemicals. A python may measure more Great length helps the python to kill its prey by squeezing the prey to death. The than 32 feet. How would this length benefit and hinder the python’s great length might prevent it from finding shelter for itself and its young. python? Also, it would need a lot of food to sustain it. In years when prey is scarce, a python might not survive. The longest snakes are those that kill their prey by suffocation— the pythons, the boa constrictor, and the anaconda. BIOLOGY: PLANTS Which appeared first on earth, A plant is he earliest form of life found thus far by scientists. In a remote part of plants or animals? Give reasons western Australia, scientists have found For your answers. what appear to be nearly the oldest rocks known on earth. These rocks are about 3.5 billion years old. They are called stromatolites and contain the fossilized remains of at least five different life forms. The fossils appear to have been formed by a pond scum, which used carbon dioxide (as do plants today) and grew in tiny strands. How can you determine the age If a tree grows in an area where there are cold and warm seasons, the annual rings of a tree after it has been cut reveal he age of the tree. Each ring in a down? cross-section of the tree’s trunk represents a year. In summer the tree grows quickly, and there are large wood cells; in winter the wood is denser and produces a dark ring. The oldest living organisms on earth are bristlecone pine trees. Some of them are 5000 yrs. Old. They were seeds when people in the Middle East first invented writing! HANDS-ON ACTIVITY Obtain cross-sections of various tree trunks from a local nursery. Display the cross- sections to the class. Challenge your students to order the tree parts from youngest to oldest. More than half of the species of Answers will vary but may include the following: conifers, such as pine, hemlock, plants in the world, over and cedar; ferns; fungi, such as 250,000 of them, are flowering mushrooms, yeasts, and molds; mosses; plants. How many plants can and algae. HANDS-ON ACTIVITY: Display some you name that do not produce examples of non-flowering plants to the flowers? class. Develop the idea that while these plants lack flowers, they do possess reproductive structures, such as spores of a mushroom. Many plants spread their seeds Some plans produce fruits that birds and other animals eat, leaving the seeds from over a wide range without help the fruit on the ground. Some plants from humans. How do these produce seeds that have special coatings, seeds travel? so that when they are eaten, they are not digested, but are expelled with the animal’s droppings. If the animals wander far, these seeds will each the ground far from the plant that produced them. Other plants produce seeds with hooks or barbs that get caught on animals’ fur and are taken for a ride. Some seeds, like those of the dandelion and the maple, are surrounded by structures that enable the wind to carry them. When bread, fruit, and other Fungi include mushrooms, molds, and yeast. The air is filled with the spores of foods are left unprotected for fungi, which are like seeds waiting to grow too long, spores if fungi begin to wherever they have the chance. Although reproduce on them. What are molds ruin food in the kitchen, in the natural world they help break down fungi? How do they get on the discarded and unneeded substances and foods? return nutrients to the environment. HANDS-ON ACTIVITY: Place a slice of bread on a dish. Wrap a second slice of bread in aluminum foil and put it on another dish. Leave the bread on a desk. Observe the breads daily, noticing any changes in appearance. CAUTION: Advise Students not to handle the moldy bread. Dense tree cover blocks light Answers will vary but may include the following: Plants that survive on the forest from reaching the floor of rain floor must be adapted to a dark, moist forests. How might flowering environment. These plants end to be more plants that grow near the forest strongly scented, since they must attract pollinating insects without the insect’s floor differ from those that grow being able to see them easily. in the canopy? Plants need light to grow. How Answers will vary. One example follows. Cut a hole in one of the narrow ends of a could you make a plant grow shoebox, put a plant inside, and put the lid sideways? on with the hole facing a sunny window. The growth of a plant toward light is called tropism. Tropism results when some cells of a plant grow faster than others. If a plant has plenty of light, it will grow straight up, but a plant can change the direction of its growth to adapt to uneven light. HANDS-ON ACTIVITY: Conduct the activity described to observe the tropism. Extend the activity by cutting various sized holes in different location of 3 boxes, placing a plant in each box, and comparing their growth patterns. Why do the flowers of some The resemblance of the orchid to a bee helps in the orchid’s reproduction. A male orchids look like bees? bee is attracted to the flower by what looks like another bee. In the process, pollen (the male sex cells of flowers) sticks to the bee’s body. When the bee flies away, it carries this pollen to the next flower, where some of the pollen can rub off and join with the seeds (the female sex cells). In this way the flowers are fertilized. Why is it possible for different The amount of sunlight, moisture, heat, and wind that a particular area of a year, field, kinds of plants to grow in the or lot receives varies greatly. The area same yard, field, or lot? under a large tree receives less sunlight than does an open area in the same yard. Even a small yard can contain a number of different microclimates suited for various types of plant life. You can map the temperature differences in a lot by using a weather thermometer to compare the temperature of soil in sunny and shady areas, in dry and damp areas, and on different sides of the same tree. HANDS-ON ACTIVITIES: Conduct a field trip to investigate the microclimates that exist in an area outside your school. Use an outdoor thermometer to identify temperature differences that exist within the area. Note variations regarding exposure to wind and water also. Conclude the activity by having students note various types of plant life found in the area. How does the strong scent of a The scent of a flower aids in the reproduction of the plant. The flower’s flower benefit a plant? scent and the color of its petals attract insects to the plant. The insects feed on the sugary nectar contained within the flower, and tiny grains of pollen cling to the insect’s body. The insect carries the pollen grain along when it moves to the next flower. As the insect drinks from another plant, the pollen falls from its body. In this manner, pollen from one flower fertilizes the eggs of another flower. The fertilized egg produces seeds that will develop into new plants. HANDS-ON ACTIVITY: You can show students how easily pollen is released from a flower by taping a fresh cut flower over a sheet of black paper. If the flower has male reproductive organs called stamens, students will see tiny pollen grains fall from the stamens onto the paper. Why do plants become more Green algae and other plants can live without oxygen, which is depleted by numerous in lakes and ponds pollution, but most fish cannot. Without that are polluted? fish and other animals to eat the plants, the plants grow thicker and thicker, finally filling the pond or lake. Oxygen is depleted in ponds and streams when nitrates and phosphates, waste products from detergents and other pollutants, are present. The bacteria that break down these waste products use a lot of oxygen. CHEMISTRY Why do you need to shake a The oil in the dressing floats on top of the other ingredients unless you’ve just shaken bottle of salad dressing before the bottle. Oil has a lower density than pouring the dressing on a salad? water and thus is lighter than water. Consequently, the oil molecules are pushed to the surface of the liquid in the bottle. Another reason that oil floats is that is does not dissolve in water. Water has electrical attraction for charged particles, but oil has no charge. Therefore, the water molecules attract one another and push the oil molecules toward the surface. HANDS-ON ACTIVITIES: Present students with a visual model that oil and water have different densities. Pour equal amounts of water and cooking oil in a glass container. Stir the liquids and observe. After dispersing throughout the water due to stirring, the oil will eventually float to the top of the container. How do salts, such as table salt, Water molecules normally form ice at 0 degrees Celsius (32 degrees Fahrenheit). keep wet roads from freezing in When table salt (sodium chloride) cold weather? dissolves in water, it separates into 2 charged particles, and the molecules of water join more strongly to the separate sodium and chloride particles than to each other. Therefore, the water molecules do not join together to form ice. HANDS-ON ACTIVITY: Present a visual model of how salt interferes with the freezing process by filling one ice cube tray with tap water and another tray with salt- water solution. Place the trays in a freezer overnight. Then compare the contents of the trays. How does detergent help When detergent is added to water in which clothes are washed, the detergent causes remove grease from clothes? the grease to mix with the water. This releases the grease from the cloth. Detergent is necessary because grease, or oil, is not broken down in water alone. Detergent molecules mix oil with water by attracting oils with ½ of the molecule and water with the other half. How does a mercury Mercury contracts when heat is removed and expands when heat is added. Of thermometer work? course, Almost everything around us reacts this way to changes in temperature, but mercury is especially sensitive and has a low freezing temperature and a high boiling Temperature. A thermometer containing a small amount of mercury can track small changes in temperature between –38.9 degrees Celsius (-38.0 degrees Fahrenheit) and 357 degrees Celsius (675 degrees Fahrenheit). HANDS-ON ACTIVITIES: Illustrate to your students how a mercury thermometer works by placing it in a variety of substances with varying temperatures. Possible mediums include ice water, tap water, and hot cocoa. After doing this, challenge students to predict the temperature range of frozen juice concentrate and a soft drink. Check the accuracy of student predictions. What do pencils and diamonds Pencils contain graphite, and both diamonds and graphite are crystalline have in common? forms of the element carbon. Diamonds are the hardest natural substance on earth. Their hardness, electrical resistance, and heat-channeling properties make them valuable to industry, as well as to jewelers. But natural diamonds are expensive and hard to find. By applying temperatures over 1400 degrees Celsius (2550 degrees Fahrenheit) and tremendous pressure to graphite, scientists can make synthetic diamonds. Why does a brown paper bag The fat in the potato chips separates from the starch in the chips and is absorbed by holding potato chips become the paper. You can tell that the potato chips discolored and soggy over time? have fat in them by looking at the nutritional information on the side of the package or can. A simple test determines the presence of fat in food: Mash the food and dissolve it in alcohol. Put a little of this food and alcohol mixture into another test tube and add water. If a milky white liquid forms, the food contains fat. HANDS-ON ACTIVITY: Prove to your students that potato chips contain fat by performing the experiment described. Repeat the experiment with other types of snack foods, such as popcorn and pretzels to identify the least fatty snack. Scientists believe that, when Photosynthesis brought oxygen into the atmosphere. Photosynthesis is the process earth first formed, its by which green plants use energy from the atmosphere contained no sun to change carbon dioxide and water oxygen at all. Today oxygen into sugars, which the plants need for growth. In photosynthesis, water is broken makes up about 21 % of the into its two components, hydrogen and atmosphere. What could have oxygen. The hydrogen is used to make the caused this change? sugars; the oxygen is not needed by the plant and is released into the atmosphere. Imagine you’re preparing a fresh You can dip the slices in water, sprinkle fruit salad for a party. How can them with lemon juice, or put them in an airtight container. These techniques you keep the apple and banana prevent oxygen from reacting with the slices in the salad from turning molecules in the fruit. When oxygen comes brown? into contact with the exposed flesh of some fruits, a series of chemical reactions. Begins. These reactions create the brown pigment that covers the exposed part of the fruit. Water coats the surface of the fruit to prevent oxygen from reaching it for a while. The vitamin C in lemon juice bonds with the oxygen to prevent it from reacting with the molecules of the fruit. An airtight container prevents oxygen from reaching the fruit. HANDS-ON ACTIVITY: Model this concept by placing fresh apple slices in three types of containers. Put some slices in an uncovered bowl. Put other slices in an airtight container. Dip additional slices in lemon juice and put these in an uncovered bowl. Leave the containers on a table over- night. Observe the results. Why is it impossible to burn a Oxygen is needed for combustion, and the molecules in a block of metal are bonded block of metal but possible to too tightly to mix the oxygen and burn. burn ribbons of metal? Threads and ribbons of metal burn well because they have a lot of surface area, which allows more of their molecules to come in contact with oxygen molecules. Steel wool, for example, burns quickly. Magnesium threads burn quickly and brightly and are used in flashbulbs. Aluminum is used for pots and pans because it doesn’t burn on a stove. In powdered form, however, aluminum ignites so violently that it seems to explode. Water is part of almost You could put an ounce of fresh carrot in a 150-degree oven for several hours, and everything you eat. If you take then weigh it. After drying, the carrot will an ounce of fresh carrot, dry it, weigh about ¼ of an ounce. So you know and weigh it again, you can you that a fresh carrot is about three-fourths water. find out how much water it contains. How could you dry a fresh carrot so that you can get this information about it? Arrange in order the steps in the Organic matter sinks to the ocean floor. Then it is covered by sediment. Forces of formation of oil: pressure and heat work on the organic Organic matter is covered by matter for millions of years, gradually sediment. transforming it into liquid or gaseous hydrocarbons. Finally, a layer of porous Organic matter sinks to the rock traps the hydrocarbons in an area ocean floor. called a sedimentary basin. A layer of porous rock traps the hydrocarbons in an area called a sedimentary basin. Over millions of years, pres- sure and heat transform the matter into liquid or gaseous hydrocarbons. Bananas ripen because of the You could place green bananas in a bowl with ripe banana or with other fruit. You effects of ethylene gas, which is could also put green bananas in a paper released by mature bananas and bag. This will concentrate the ethylene gas by other fruits, such as in the air around them. Banana dealers and supermarkets place bananas in chambers tomatoes. How might you ripen filled with ethylene gas. green bananas? HANDS-ON ACTIVITIES: Hold a ―Ripen-off‖ to check the accuracy of some of the students’ methods of ripening fruit. Challenge the class to identify the scientific principle behind each methods tested. ENVIRONMENTAL STUDIES The canopy of a rain forest is an The canopy is protected from the most intense sunlight, yet it gets enough sunlight extremely dense layer of vines, for thick vegetation to grow. It offers its treetops, and plants. Why do inhabitants protection from ground you suppose so many species predators, as well as a rich food source. In addition to thousands of species of birds, live there? plants, and insects, as many as half the mammals in a rain forest may live in the canopy. The canopy is approximately 30- 40 meters (100-130 ft.) above the ground. How does acid rain, which Crayfish in an acidified lake cannot produce enough calcium for their contains toxic acids from exoskeletons. They produce fewer industrial wastes and automobile offspring and have increased problems exhaust, affect crayfish, frogs, with parasites. Frogs, toads, and salamanders are also extremely necessary toads, and salamanders and their for their hatching. Animals that prey on predators? crayfish and amphibians are affected because their food source is depleted. The Hawaiian Islands, because The earliest plant life could have arrived in Hawaii in any of three ways. Seeds could they were formed by volcanoes, have been driven there by storm winds, were barren lava rock when they stuck to a bird that was blown off course, rose out of the sea. How did or washed up on the beach after days in the ocean. Plants can be transported by plant seeds get to Hawaii? people—sometimes willfully, sometimes accidentally (for example, a seed stuck to someone’s shoe). The earth’s population has According to some predictions, more than 10 billion people will live on earth by the doubled since 1950 to about 5 year 2100. Population growth slowed billion people. The population somewhat between 1950 and 19990. If it will double again by 2100, had not slowed, predictions would estimate 10 billion people on earth by 2030 and according to predictions. What about 35 by 2100! will the population be then? The world’s six most populous In order of decreasing population, the countries should be ranked (1) China countries are the United States, (1,151 million), (2) India (866 million), Russia, China, Indonesia, India, (3) the United States (249 million), And Brazil. Rank them (4) Indonesia (193 million), (5) Brazil (154 million), according to population. (6) Russia (149 million). Gulls usually lay only 3 eggs. Gulls, like other birds, lay the number of eggs that will produce as many adults as Gulls can usually feed only 2 possible. This number is determined partly young in a season, and they are by the amount of food available and partly likely to lose at least one of the by the likelihood that an egg or a young bird will fall prey to a predator. Birds young to a fox or other predator. instinctively know how many eggs to lay. How do gulls ―know‖ they should lay 3 eggs? Lead is a heavy metal that is To prevent lead from entering our bodies, we must keep it out of our food chains and highly poisonous to humans. water supplies. We must handle lead with How can we prevent lead from care and dispose of it properly. Lead can be entering our bodies? found in roofing materials, X-ray shields, building foundations, cables, and cars. Carbon dioxide is a waste You can try not to waste household heat and hot water, which are usually produced product of burning fuel. Carbon using oil or gas. Turn down the thermostat dioxide emissions must be and use cool water instead of hot water. reduced in order to keep the You can also cut down on car travel by using public transportation or by walking. earth’s temperature stable. How Finally, you can plant trees and green can you help reduce carbon plants, which absorb carbon dioxide and dioxide emissions? turn it into oxygen. If the earth’s climate were to get Answers will vary but may include the following: (1) Some islands might warmer, oceans would grow disappear entirely. (2) Vast areas of land larger as glaciers melt into them. along fertile river deltas would be lost. Predict 3 things that might (3) Large settlements near beaches would wash away as shorelines receded. If there happen if the earth’s oceans were a one-foot rise in sea level, the increased substantially in size. Maldives and the Marshall islands would disappear, Egypt would lose 15 % of its best farmland along the Nile, and shorelines would recede between 100 and 1000 feet, depending on their steepness. Which of the following causes Pollution from factories, sewage, and other land-based activities accounts for about the greatest amount of pollution 90% of ocean pollution. Anything dumped in the oceans? into rivers or emitted into the atmosphere Land-based activity usually ends up in the oceans. This pollution has countless direct and indirect Offshore oil drilling effects on the oceans and marine life, one Water transportation of which is to disturb the balance of Ocean dumping oxygen in the water. Oxygen loss threatens the existence of some species of marine life Seabed mining and may lead to an imbalance among species. If the cans discarded in a year Answers will vary but should reflect an original use for discarded cans, such as were laid end to end, they would filling the cans with rocks and connecting reach to the moon and back them to form a fence or cutting off the tops about 8 times. Can you think of and using the bases as candleholders. The ecologist Robert Wallace, writing in the an imaginative use for discarded early 1990’s, said that nearly half of the 80 cans? billion aluminum cans made in the U.S.A. each year are discarded instead of recycled. See if you can find out what percentage of the cans in your community is discarded rather than recycled. HANDS-ON ACTIVITIES: Encourage students to make a model of their alternate use of a can. The inventors should then share their models with the class. You may even choose to hold a ―Can Fair‖ and display the creations around your classroom. Much of the rain forest in the Increased population and demand for wood, meat, and farmland have resulted in world has been destroyed, and the loss of much of the tropical rain forest there is great concern about the in South America and Southeast Asia. loss of this important resource. Demand by industrialized nations, such as the United States, Japan, and the countries What is causing the destruction of Europe for wood, beef, and cheap feed of the rain forest? for livestock induces people living near the rainforest to clear cut, or lay bare, a section of rain forest to harvest the wood and use the land to graze cattle or grow crops. There are only about 3 or 4 The ozone layer is crucial to life on earth because this thin layer of gas protects earth ozone molecules for every from harmful ultraviolet radiation from the million molecules of gases that sun. Ozone is a very unstable form of make up air. Why is the ozone oxygen that is constantly breaking apart, but under normal conditions fresh ozone is layer so important to life on constantly being formed. When earth? chlorofluorocarbons (CFCs), chemicals used in air conditions and refrigerators, break down the stratosphere, they destroy ozone molecules much faster than they can be replaced. Krakatau (which used to be The explosions spewed an enormous amount of ash and dirt into the earth’s called Krakatoa), an island in atmosphere, where it dispersed gradually. Indonesia, exploded in a huge Particles of ash and dust in the air affect volcanic eruption on Aug. 27, the paths of the different wavelengths of sunlight. Short-wavelength light travels a 1883. For several years much longer path than long-wavelength afterward, brilliant sunsets were light to reach the same distance and is apparent all over the South easily deflected by dust particles. Red light has the longest wavelength of visible light, Pacific. Why? so it passes more efficiently through the dust in the air. This is why brilliant pink and red sunsets result when a lot of particles are in the atmosphere. Acid rain is a pollution problem The automobile burns oil and gasoline for that has grown worse in the last energy. The burning of these fuels releases sulfur dioxide and nitrogen dioxides into 30 years. How does the the air. Acid rain forms when water vapor automobile contribute to this in the air reacts with chemical compounds problem? such as sulfur dioxide and nitrogen dioxides from fuel combustion. These acids react with water to form harmful substances, sulfuric and nitric acids. Although any one rainfall may contain only small amounts of these acids, over time they accumulate, polluting lakes and rivers and killing fish and other marine life. Estimate how much water you Each American uses an average of 2000 gallons of water per day. Think about how use each day. (Remember that you use water—for showers or baths, farmers use water to raise the brushing your teeth, drinking, and cooking. plants and animals that supply You also use water in less obvious ways. For example, it takes about 75 gallons of your food). water to make one egg, and 150 gallons of water to make a loaf of bread. A pound of beef ―costs‖ 2500 gallons of water; cattle not only drink water but also consume plants, which require water. Water is also used to create power—for example, it cools power plants. Manufacturers use about 100,000 gallons of water to make a new car. GENETICS In each human cell, the 23rd pair A female has two X chromosomes; a male has an X chromosome and a Y chromo- of chromosomes determines a some. If the X chromosome carries a gene person’s sex and certain other for colorblindness, a female has another traits, such as colorblindness. X chromosome, which may carry a gene for normal vision and cancel out he Why do you think colorblind- colorblindness. A male, however, has only ness. Why do you think color- one X chromosome. If this chromosome blindness occurs more often in carries a gene for colorblindness, there is no gene for normal vision to cancel out the males than in females? colorblindness. In 1791 a farmer discovered that When the lamb grew up, it couldn’t jump over fences. The farmer liked this, so he one of his new lambs had very bred this sheep and the short-legged lambs short legs, unlike those of its that it fathered. Soon the farmer had a parents. How might this whole herd of short-legged sheep that couldn’t get out of the pasture. Of course, mutation, or difference in the this mutation was more useful to the farmer lamb’s formation, have proven than to the sheep! Can you think of a mutation that might be useful to the animal useful to the farmer? itself. HANDS- ON ACTIVITY: Your students may enjoy sketching an animal that possesses a beneficial mutation. You might even have them name their ―new‖ animals. For example, a rabbit that had strong hind legs like a kangaroo could be called a ―Bunniroo.‖ What is the difference between Identical twins have the exact same genes. They develop from the same fertilized egg, fraternal and identical twins? which means they look identical and are the same sex. Fraternal twins come from 2 different eggs, so they do not necessarily look the same and may be of different sexes. Identical twins not only look alike, they often lead similar lives. Studies involving identical twins who were adopted at birth by different families have found that these twins often have the same occupations, make similar decisions about their lives, get the same diseases, and sometimes marry people that are similar to each other. Why might one person have Curly hair is a trait, or characteristic, that is determined by a message on a gene. You curly hair and another have carry a pattern of genes in each of your straight hair? cells, and they contain information about hereditary characteristics from past generations. If both your biological parents have curly hair, you are likely to have curly hair too. Your parents have passed on the gene for curly hair to you. Straight hair is a trait that is determined by a different message on the gene. If both your parents have straight hair, you are likely to have straight hair too. What do you think occurs when one parent has straight hair and the other parent has curly hair? Thousands of years ago, people Skin color is one of the ways that humans have adapted to different environments. did not travel far, so they lived People in the cold climates of the far North generation after generation in needed light skin because it allowed the the same climate. Why do some sun’s rays to produce vitamin D, an essential nutrient for humans. Dark skin human beings today have lighter reflects sunlight and thus can prevent the skin than others? production of vitamin D. Therefore, babies born with dark skin the these cold climates were not likely to survive. The skin pigment called melanin makes skin darker. In hot climates, where the sun’s rays reach the earth more often than they do in a cold climate, babies born with more melanin, and thus darker skin, tended to survive better. GEOLOGY What’s the difference between a Glaciers are masses of ice that travel across the land; icebergs travel on the sea. glacier and an iceberg? Glaciers are formed when snow falls faster than it melts. The pressure from many layers of snow turns the bottom layers into ice, and the weight of the ice and snow makes the glacier slide across the land, moving slowly downhill a few inches a year. Most icebergs are masses of fresh- water ice that have broken off from glaciers or ice shelves (a layer of ice that is connected to the land but that floats on the sea. On a map of the world, the east Many geologists think that about 250 million years ago there was a single large coast of South America and the continent on the earth that they call west coast of Africa look as Pangea. It was surrounded by a single though they would fit together enormous ocean called Panthalassa. Since that time, like two pieces of a jigsaw According to this hypothesis, parts of this puzzle. Why might this be so? large continent have broken off and have slowly moved to different places on the planet, forming the seven continents that we know today. What natural event makes the About once every second, an earthquake occurs somewhere in the world, but most surface of the earth tremble of these earthquakes are too minor to be about 1 million times a year but felt. Even small quakes register on a only occasionally results in seismograph, an instrument that measures earthquake shocks. Several hundred massive destruction? How is earthquakes per year are not only felt but this natural event measured? also noticed because of their effects. These earthquakes change the land in some way. Occasionally, major earthquakes result in widespread destruction, leaving thousands of people homeless. A geologist can tell the Diamonds are much harder than quartz, and the sandpaper test checks the hardness difference between clear quartz of the mineral. Sandpaper can scratch and an uncut diamond by quartz, but it cannot scratch a diamond. rubbing each with sandpaper. Geologists have several ways to identify rocks and minerals. They look at a rock’s Why would this test help to color and the way it reflects light. They get identify the minerals? clues from the shape of a mineral’s crystals and the way the mineral breaks. Geologists also test the way different rocks react to different chemicals. Solids usually turn into liquid The core of the earth is a ball of dense iron and nickel. The temperature of the core is and eventually into gas when extremely high due to heat from they are heated enough. Yet the compression and radioactive decay. In Center of the earth, the temper- spite of these forces, the core remains in a solid state due to tremendous pressure and ature of which is believed to be lack of atmosphere. about 3,700 degrees Celsius (6,700 degrees Fahrenheit), remains solid. Why? Why is a grain of sand in the A grain of sand in the desert is usually rounder than a grain of sand in the ocean desert usually rounder than a because in the desert the grains constantly grain of sand in the ocean? rub against each other. This happens in the ocean, too, but there the grains are cushioned by the surrounding water. Sand is made of tiny particles of quartz or other minerals. Often the sand on a beach also contains tiny bits of coral or shells. Sand in some deserts contains particles of shells, even though it is not near the ocean. This sand may have formed in other places and been carried by the wind to the desert; or the sand may have formed when the area was an ocean, millions of years earlier. Where are the most of the Most of the world’s active volcanoes are found along the Pacific Rim, where many world’s active volcanoes? of the tectonic plates of the earth meet and overlap. Tectonic plates are the huge sections of crust that makeup the earth’s surface. A ―ring of fire‖ of active volcanoes Encircles the Pacific from New Zealand in he south, northward through Papua New Guinea, Indonesia, the Philippines, Japan, and Korea. This ring continues southward along the Aleutian Islands and down the coasts of Alaska, Canada, the western United States, Mexico, and the Andes Mountains of South America. Why are spectacular canyons Canyons are created when a powerful river travels through very dry land. In parts of found in the western United the world where there is abundant rainfall, States but not in other areas of runoff from the land’s surface gives most the country? rivers gradual, sloping banks. In the Rocky Mountains, however, abundant rain and snow create fast-moving rivers, but the land these rivers travel through after leaving the Rockies is very dry. Very little water runs into the rivers from the surface of the land. As the river cuts through the rocks it leaves steep, nearly vertical walls. HUMAN BODY: DISEASE What major health problems do Smokers are almost 20 times more likely to develop lung cancer than are nonsmokers. smokers face? Smokers also risk mouth, lip, larynx, pancreas, and urinary bladder cancers. Smokers have at least twice as great a risk of dying from a heart attack as do nonsmokers. Mothers who smoke have more miscarriages than do mothers who do not smoke; children born to these mothers have a lower average birth weight than those born to nonsmoking mothers. Other risks resulting from smokers’ exposure to more than 1000 chemicals each time they light up may yet be discovered. How does a vaccination help a Vaccination shots give immunity, or protection, from certain diseases. A person stay healthy? vaccination shot puts in the person’s body a preparation of the same bacteria or viruses that cause the disease that the vaccination protects against. The bacteria or viruses in the vaccine are very weak, or even dead. However, the body of the person who has had the shot makes antibodies that fight that particular kind of bacteria or virus. This means that, if the person is exposed to that particular disease, the body already has built up antibodies to fight the disease. Why is there a shot that can Human immunodeficiency virus (HIV), which is associated with AIDS, attacks the protect you from getting body’ immune system, or defense system. measles but no shot that can Consequently, it is much harder to figure protect you from getting AIDS? out a way to help the body’s immune system fight this deadly virus. Vaccines against viruses, like the measles vaccine, work by helping the immune system build up a defense against the virus that carries the disease. When the body is inoculated with a milder form of the virus, the immune system is able to ―recognize‖ and fight the more serious virus when it appears. Why do you think some elderly Many people in their 70s and 80s suffer from Alzheimer’s disease, which causes people experience loss of severe confusion and loss of memory. This memory? disease is linked to age: 5% of people over 65 have the disease, and 50% of those over 85 have it. No one knows yet what causes Alzheimer’s disease, but it makes brain cells die, causing the brain to shrink. Alzheimer’s disease also tangles up the neurons, cells in the brain that conduct electrochemical impulses. The sun-protection factor (SPF) SPF 4 lets you stay in the sun without burning 4 times longer than you can of sunscreen tells you how many without sunscreen. SPF 16 lets you stay in times longer you can stay in the the sun 16 times longer. So SPF 16 lets you sun without burning than you stay in the sun 4 times longer than does SPF 4. Overexposure to the sun, especially could if you used no sunscreen. to ultraviolet light, results in premature How much more protection do skin aging and may produce skin cancers, you get from SPF 16 from as well as sunburn. SPF 4? Suppose you have discovered a You can design an experiment to test the drug by comparing what happens to a drug that you think will cure group of ill persons who are given the drug cancer. How can you design a with what happens to a control group who good experiment for testing the are ill but not given the drug. The control group is necessary because otherwise drug? researchers would not know if those who improved after taking the drug would have done so even without having taken it. HUMAN BODY: NUTRITION Why might it sometimes be Certain vitamins can be toxic if taken in large quantities. In particular, Vitamin A dangerous to take vitamins? and D remain in the body in fat tissue rather than being excreted if they are not used. Symptoms of Vitamin A poisoning include irritability, fever, and bone pain. Symptoms of Vitamin D poisoning include loss of energy, loss of appetite, and the presence of kidney stones or kidney failure. What’s the best food to eat The night before a big test, have a bedtime snack that’s high in carbohydrates, such as before a test or an exam? a muffin, or toast and milk. Carbohydrates will help you get a good night’s rest. A high-protein breakfast on the morning of the test will help keep you clear-headed so that you’ll be able to remember what you studied. Is it possible for you to gain Yes. Many of the things people put on salads are high in calories. Most salad weight if you eat only salad for dressings are very fatty. You can avoid lunch every day? Why or why these fats by putting low-fat or no-fat not? dressing, or lemon juice, on your salad. Avocados, olives, sunflower seeds, croutons, and most cheeses, which are often used in salads, are high-fat foods. Marinated vegetables, cole slaw, pasta salad, and potato salad are also usually high in fat because of the oil or mayonnaise used in preparing them. Salads of raw vegetables and legumes such as chickpeas can be low in fats and are good sources of carbohydrates and proteins. What would be more harmful to Water is the most important thing you consume. Without solid food you can your body—to be without solid survive for weeks, but without water you food or without water for a can live for only a few days. Water carries week? nutrients to your cells and cleans waste from your body. Each day, you must replace the water lost through urine, perspiration, and breathing. Most foods contain water—even meat is half water— but you should drink several glasses of water each day for good health. What is the most widely eaten Grains, such as wheat, corn, and rice, are the main kind of food eaten by human food in the world? beings and domesticated animals through- Out the world. These grains can be eaten whole or ground to make flour for bread, tortillas, or noodles. Grains are rich sources of carbohydrates and contain protein and natural oils. They can be stored for long periods of time. Wheat, rice, and corn are among the oldest cultivated plants. Today, half the world’s croplands are used to raise grains. HDL cholesterol collects un- HDL cholesterol is better for you because it removes unneeded cholesterol from the needed cholesterol and removes cells. A good health goal is to raise the it from cells. LDL cholesterol amount of HDL cholesterol relative to the picks up cholesterol and total amount of cholesterol through exercise and proper diet. deposits it in cells. Which type of cholesterol is better for you, and why? Are insects a nutritious source Insects are just as nutritious as chicken or beef. Although most North Americans and of protein for humans to eat? Europeans find the idea of eating insects Why or why not? disgusting, this attitude results from thousands of years of habit, rather than because insects taste bad or are unhealthy. The food people eat depends partly on what can be grown, raised, or found where they live. Many people in the tropical forests of South America and Africa eat and enjoy insects, worms, and spiders that abound in those regions, where cattle, pigs, sheep, and chicken are rare. A doctor examines symptoms 1 b, 2 a. Red, peeling areas of the lips suggest that the patient’s diet may not when diagnosing an illness. include enough vitamin B. One symptom Match the following symptoms of anemia (iron deficiency) is a sore with possible illnesses: tongue, or one that is smooth and shiny. Symptoms Illnesses 1. red, peeling lips a. anemia, or iron (Hint: Vitamin B deficiency keeps lips moist) b. vitamin B 2. smooth, shiny, sore deficiency tongue (Hint: Iron keeps tongue surface healthy) HUMAN BODY: SYSTEMS Why does a doctor sometimes Doctors usually take blood to do a complete blood count (CBC). This test take a sample of your blood screens for anemia. Blood may also be when you have a checkup? checked for cholesterol levels, or blood sugar levels, or exposure to bacteria or viruses. Look at this blood chart. Which Type O blood is acceptable to anyone, no matter what their blood type. Type AB blood type can be used as a blood can receive any of the four blood donor for any other type? Which types But it is best, however, to receive the blood type can receive blood of same type of blood that is in your body. For example, a person whose blood type is any type? AB should receive AB blood, unless there Donor Patient is an emergency. AB AB A AB A B AB B O AB A B O Adrenalin helps people survive 1 c, 2 b, 3 a, 4 d. The heart pumps faster so that it can send more blood to the muscles. in an emergency by carrying Breathing becomes faster so that the lungs messages to different parts of take in more air, providing more oxygen the body. Match each for muscles. Red blood cells are released so that the blood can carry more oxygen, emergency response to a reason which is needed by the cells. Blood clots that it occurs. quickly so that bleeding is reduced. Response Reason 1.Heart pumps faster a. blood can carry 2.Breathing speeds up b. lungs take in more air 3.Red blood cells are c. heart sends released more blood to the muscles 4.Blood clots quickly d. bleeding is reduced A major problem in organ and The immune system protects the body from viral and bacterial infections by identifying tissue transplants is rejection: what belongs in the body and what does that is, the body’s immune not. Tissues from other people bear system recognizes the trans- different hereditary markers, so the immune system treats them as if they do planted tissue as alien and not belong. One way to prevent rejection is destroys it. Why does this to use a sister or brother of the patient, happen, and how can it be preferably an identical twin, as an organ donor. People closely related share more prevented? hereditary markers. Laboratory technicians can do tests before a transplant to make sure the match is good between the donor’s tissue and that of the recipient. Many people suffer from hay Hay fever is not necessarily caused by hay. Hay fever is an allergic reaction that can be fever. How is his condition caused by pollen from many kinds of related to hay? Does it cause a grasses and flowers. When the body has an fever? allergic reaction to pollen, it reacts as if the pollen were a poison. Body cells release an irritant called histamine, which can cause a runny nose, sneezing, and itchy eyes. Medicines that control the effects of histamine are called antihistamines. When you are sitting in a Since your body can’t really adjust for the movement of a car, the messages from moving car, the fluid in your your inner ear can create dizziness and inner ear moves. This process nausea. Fluid in your inner ear gives your can cause some people to body its sense of balance. If you start to trip when you’re walking, movement of become carsick. Why? this fluid alerts you to catch yourself right away, even before you have a chance to think about what’s happening. Some people can adjust to motion from cars, boats, and other vehicles, while others develop motion sickness. What might cause your leg to The twitching happens because nerve fibers in your leg suddenly tighten at the twitch just as you are about to same time. This phenomenon is called a fall asleep? hypnic jerk. Sleep specialists also study another muscular spasm that occurs regularly during sleep, called a myoclonic jerk. Match each area of the brain 1 b, 2 a, 3 c. The human brain is extremely complex and has different areas that are with its function: responsible for different functions. The Area Function cortex, which is the outer layer of the 1. cortex (Hint: a. controls balance brain, is a message center that controls makes humans and posture actions and thought. The cerebellum different from controls balance and posture. The animals) hypothalamus controls responses to basic 2. cerebellum: b. receives and needs, such as food, sleep, safety, and (Hint: helps in processes signals; affection. walking and controls actions, and dancing) speech, and creativity 3. hypothalamus c. controls responses (Hint: shared to basic needs by humans and animals) What causes hiccups, and what Crying, laughing, and gulping can all cause hiccups. When people swallow large stops them? amounts of air while laughing, crying, or eating, the stomach stretches. When the stomach stretches, the diaphragm, a sheetlike muscle under the rib cage, moves up and down too fast. Air rushes into the lungs, causing the glottis (the opening to the trachea, or windpipe) to snap shut. This causes the ―hic‖ sound. Although people have many so-called remedies for hiccups, the best thing is just to wait. Hiccups usually go away on their own. MEASUREMENT Put these prefixes in order from The correct order follows: pico-, which means ―one-trillionth‖; nano-, which smallest to largest. The two means ―óne-billionth‖; micro-, which smallest have been numbered means ―one-millionth‖; milli-, which for you: (Hint: The prefix deci- means ―one-thousandth‖; centi-,which means ―one-hundredth‖; and deci- which means ―one-tenth‖, and micro- means ―one-tenth‖. These prefixes can be means ―one-millionth.‖ attached to units of measure to make them micro- milli- pico- (1) deci- smaller. For example, the micron is a very small unit of measure. It can be use to centi- nano- (2) measure the width of a strand of hair. Which line is longer? Most people perceive the vertical line as longer, but both lines are the same length. Measure them, and you can confirm this. The perception of vertical lines as being longer than they are and horizontal lines as being shorter than they are is a common illusion. This kind of illusion suggests that much of what we see is based on how we have learned to look at things. Although we see with our eyes, our brains make sense of what we see. The center of gravity is the point You can find your center of gravity by getting down on your hands and knees and at which all of an object’s placing a block on its side one cubit in weight is considered to act. How front of your knees. (A cubit is the distance can you find your center of from your elbow to the tip of your middle finger.) Then, with your hands behind gravity? your back, lean forward and try to knock the block over with your nose. Notice the point at which you fall over (if you do). Your center of gravity moves forward as you do, and if it gets beyond your knees in this experiment, you lose your balance. Experiment by placing weights in your pockets or on the backs of your calves. How do these weights affect your center of gravity? HANDS-ON ACTIVITY: Have the students perform this experiment to identify their center of gravity. Make note of how many students lose their balance. Challenge the class to analyze their observations to determine whether a relationship exists between height and center of gravity. Distances in the United States The metric system is the standard for scientific measurement throughout the are measured in miles, not world and has been adopted by most kilometers. Why do we study industrialized countries. One of the the metric system in school? practical reasons for us to study the system is for travel outside the United States. Any kind of scientific measurement is in the metric system, even when done by U.S. scientists. The metric system, which was developed in France and adopted there in 1799, uses the meter as the standard for measuring length and the kilogram for measuring mass. The meter is the distance traveled by light in a vacuum during about 3 billionths of a second. The kilogram is the mass of a particular piece of platinum- iridium metal that is preserved at Sevres in France. HANDS-ON ACTIVITY: Have students create a poster or collage of items that use the metric system of measurement. Items that might be included in the displays are canned goods labels, pictures of glassware used in a laboratory, and prescription labels. Mount Everest is the tallest First, you could photograph the mountain from a space shuttle. You could make sure mountain on earth. Suppose you that a network of points on the ground, were asked to make a new map whose positions were known exactly, could of this landform. Make a list of be clearly identified in the photographs. steps you would follow in Finally, you could get cartographers, or map makers, to compare the space pictures completing your task. with older maps and to draw all the details of Everest’s cliffs and glaciers onto the final manuscript map. The process would take a long time. In fact, Everest’s carto- graphers completed only 1 square inch of work in a day. Time zones were first establish- The railroads made time zones necessary because trains cover great distances in a ed in 1882 with the coming of short time. Without standard time zones, the railroads. Why did railroads variations in local timekeeping cause make time zones necessary? confusion. Before the coming of the railroads, many areas had their own standard for time. For example, not all countries started a new day at 12:01 A.M. A day could start at sunrise, at noon, or even at sunset, according to local custom. The United States was too large to have a single national time, so in 1883 it established 3 time zones. In 1884 an international body established a system of global time zones. METEOROLOGY Wind speed can be measured Moving air fills the cups and makes them spin. As the cups spin, they trigger an with an instrument called an electrical contact. The number of rotations anemometer, which looks like a in a given period time is recorded and the horizontal windmill with cups at wind speed is calculated from this. the end of each spoke. How HANDS-ON ACTIVITY: Challenge groups of students to design a ―homemade does an anemometer work? anemometer‖ using common materials such as paper cups, straws, pipe cleaners, and paper fasteners. Mount their creations outdoors and observe the capability of each device to measure wind speed. A thermal inversion is a weather Layers of air turn over in a thermal inversion. Usually the warmest air is condition. What gets inverted, nearest the ground. Pollutants are trapped or turned over, in a thermal between the cool air below and the warm inversion? How might a thermal air above. These pollutants—particles and noxious gases—reflect the sun away from inversion harm living things? the ground, keeping the cool air down. This inversion causes air-quality problems. The layer of trapped particles and gases is called smog. The air over the ocean is cooler As the land warms through the afternoon, it heats the air. The higher pressure of the than the air over land, and warm warm air creates an updraft, which pulls air has higher pressure than cool the cooler ocean air inland. As the land air. At the seashore, why does cools at night, the inland pull weakens and eventually ends. the afternoon wind usually flow inland? The Santa Ana is a hot, drying The Santa Ana is dangerous because it can easily pick up a spark, ignite a fire, and wind that parches the forests and spread the fire for more than 100 miles. fields over which it blows. Why Also called the Witch’s Wind, the Santa is it so dangerous? Ana is formed when high-pressure air from Western Canada blows toward low- pressure air over the Pacific Ocean. The resulting wind blows through the Santa Ana Canyon toward Los Angeles, Santa Barbara, and Mexico. In an electrical storm, you Lightning will go to its nearest conductor. You will be that conductor if you are the should avoid touching metal highest point in the landscape, such as on outside and should stay away an open beach or on a hilltop. Water from water and from places conducts electricity very well, as does metal, so you should keep away from water where you will be the highest and metal if you have to be outdoors in a point in the landscape. Why? lightning storm. Inside a car is a safe place in a lightning storm, if you are not touching windows, because the car body shields you. How were sailors able to predict Sailors knew which way the winds usually blew in each latitude (horizontal band winds so they could sail in the around the earth) at each time of year. direction they wanted to go in They could estimate their location by the days before steam-driven testing the wind. Then they could decide which latitude they should seek to carry navigation? them most quickly to their destination. The spinning of the earth, and the constant movement of hot air (which rises) at the equator and cold air (which falls) at the poles, twists these winds in a predictable pattern. Try this experiment to determine wind direction: On a breezy day, go outside, wet your finger, and hold it up in the air. The side of your finger that is cooler is the direction from which the wind is blowing. HANDS-ON ACTIVITY: Have students use the method described to identify the direction wind is blowing each day during a to-week period. Ask a recorder to log the daily observation. At the end of the two weeks, analyze the data to identify any patterns that exist. El Nino is a warm current that El Nino could cause sea life to disappear: marine animals would die because their occurs occasionally in the systems cannot tolerate the heat. This Pacific Ocean. El Nino heats up heating of the ocean can also have a the normally cool waters off the dramatic effect on climate. A particularly disastrous El Nino occurred in 1982 and west coast of South America. 1983, affecting climates all around the What problems could El Nino Pacific. It resulted in the worst drought in cause? Australia in 100 years, floods on the west coast of South America, and a record snowfall in the Rocky Mountains. What causes lightning? Does Electrical energy builds up in a thundercloud because strong air currents lightning always go from the rise and fall next to each other. Large drops sky to the ground? of rain in the falling air smash into smaller drops strip electrons from the rising drops. When the difference in electrical charge is strong enough, electric energy is released, resulting in lightning. The flash may go from the sky to the ground, from the ground to the sky (forked lightning), or between clouds (sheet lightning). During which season do most Most thunderstorms happen during the summer when the ground gets hot. . Hot air thunderstorm occur, and why? rises, so the hotter the ground, the stronger the updraft. As warm moist air rises, cool air, which is heavier, sinks to replace it. Clouds form when moisture in the rising air cools and changes from a vapor into water and ice. As the air, ice, and water swirl around, static electricity builds up (much like static electricity that builds up when clothes tumble about in a dryer). The release of this static electricity results in lightning and thunder. Monsoons are winds in the In summer, the air over land is warmer and lighter than the air over the ocean. The hot western Pacific that cause the summer air rises and is displaced by the summer rainy season in cool, moist wind blowing in from the Southeast Asia and the western ocean, which brings heavy rains. In winter, Pacific islands. The wind blows when the air over the land is cooler and heavier, the direction of the wind is southwest from the ocean to the reversed. The wet winds blow out to sea, land in summer. Why does this and drought occurs on the land. Today the bring rain? term monsoon is often used to mean winds carrying heavy rain anywhere in the world. Why must climbers wear As climbers travel higher above sea level, air pressure decreases. At 5000 meters oxygen masks at high (16,400 feet), the air pressure is so low that elevations? breathing becomes difficult. Although we aren’t aware of it, we are constantly bombarded by billions of air molecules. The action of these molecules creates air pressure, which is greatest at sea level, where the earth’s gravity makes the atmosphere most dense. In cold weather the edges of a The land does not hold heat and cold as well as water does. When cold air comes lake freeze before the middle in, heat is transferred from the ground to does, but in warm weather the the air more quickly than from the water to edges of a lake thaw first. Why? the air. The water next to the shore loses its heat to the cooled earth. Likewise, when warm air comes in, heat is transferred to the ground more quickly than to the water. The ice near the shore is warmed by the heated earth and begins to melt. How does a rainbow form? A rainbow is created when drops of moisture in the air separate sunlight into colors. The drops of moisture act like prisms, splitting the light into a spectrum of colors—red, orange, yellow, green, blue, and violet. The light is refracted, or bent, by the water drops. The amount of refraction for each color is always the same, so the colors always appear in the same order. Red always refracts the most light, and violet always refracts the least. Although the rainbow may appear to exist at a specific point in space, it does not. If you could reach the end, the middle, or the top of a rainbow, you would find only white light, air and moisture. HANDS-ON ACTIVITY: Use a flashlight, a prism, and a sheet of black paper to show the class he visible spectrum. Place the black paper behind the prism. Shine the flashlight on the prism and watch as a rainbow of color appears on the paper. OCEANOGRAPHY Fish that live at the bottom of Many fish that live in very deep water have eyes that are directed upward, so they see the ocean, where it is very dark, their prey’s silhouette against the faint light have developed adaptations for from above. Usually their eyes are very finding prey, avoiding hunters, large, helping them to see a faint light. Some deep-sea fish, squid, and worms and attracting mates. What do flash when they are disturbed or give off you think some of these light in distinctive patterns in order to find adaptations are? mates. A few fish, such as the flashlight fish, have a special kind of luminous, or glowing, bacteria in pouches under their eyes. This fish can flash by covering the lighted pouch with a membrane, like a human eyelid, alternating blacking out and giving off the light. The flashlight fish uses its light to search for food and to lure its prey. How do you think sharks find Sharks have some keen senses. For example, their hearing is excellent. They their prey? can hear the thrashing of an injured fish more than ¼ mile away. Sharks also have a sharp sense of smell. Two-thirds of the shark’s brain processes information about smells. A shark’s sense of touch is highly developed as well. Fluid-filled canals beneath the surface of the skin enable a shark to detect subtle vibrations. Sharks can also locate prey by detecting its electrical field. Most species of shark eat mainly A few sharks, such as he tiger shark, eat large marine animals such as seals or sea fish. Why might some sharks turtles. The tiger shark might attack a occasionally attack people? surfer because from below, the surfer’s arms and legs extending from the board, the surfer looks like a seal or a turtle. Why is ocean water salty while Streams and rivers above sea level carry small amounts of salt from the earth’s water in most streams and rivers rocks and soil into the ocean. From the is fresh? ocean the salts can go nowhere lower. As a result, salt builds up in the ocean. Most of the salt in the sea is sodium chloride, or table salt, but se salt includes many other minerals as well. These minerals are essential to plankton and other tiny plants that support many small fish, which in turn are food for larger fish, sea mammals, and birds. The pressure exerted by water is The pressure at a depth of 100 feet is 43 pounds per square inch (43 psi). You related to the depth of water. multiply .43 times 100 and your result is The pressure of water in pounds 43. The pressure at the bottom of the per square inch is equal to 0.43 Mariana Trench, which at 36,000 feet is the deepest point in the oceans, is 15,480 psi. times the depth of the water in Divers must consider water pressure feet. What is the pressure on because changes in pressure outside the your body 100 feet under the body affect the behavior of fluids inside the body. Divers must rise slowly from a depth water? of 100 feet or more so that their bodies can adjust to the pressure change. Amateur scuba divers should not dive below 100 feet. Since light passes through As light passes through water, the water absorbs some of the light. As water gets water, why can’t you see to the deeper, more light is absorbed. Thus the bottom of a very deep clear deepest parts of a large body of water are pool? Do you think the ocean completely dark. For centuries, people believed that the lack of light and the floor contains any living things? pressure of water made life on the floor of the deep impossible. About 150 years ago, however, scientists discovered that the ocean floor teems with life, although little is known about these deep-sea life forms. Shock waves from undersea In a tsunami, seawater shoots upward near the land, creating a wall of water 15 to 30 earthquakes can cause a meters (50 to 100 feet) high, which is tsunami. What is a tsunami, and impossible to stop. A tsunami results when why is it dangerous to seaside an undersea earthquake produces shock waves in the ocean. When one of these communities? waves enters the shallower water near a landmass and is forced into a smaller space, the wave quickly grows in height. Many tsunamis occur on the east coast of Asia, which has a lot of earthquake activity. Why are some oceans saltier Saltiness increases when an ocean or sea is surrounded by warm areas that create a than others? large amount of evaporation (water turning into vapor, or gas, leaving salt behind). For example, the Mediterranean Sea is one of the saltiest bodies of water on earth. Because salty water is very dense, strong currents are created by the sinking, sense water and the surface water that rushes in to take its place. Why are the waves in Hawaii The size of waves depends on the amount of open ocean over which the wind travels. and Australia so big? When wind blows over water, the water is set in motion like the rollers beneath a conveyor belt. This pattern of circular movement creates waves. In Hawaii and Australia there are beaches that face the largest stretches of open ocean on the earth. Therefore, the waves are very big. PALEONTOLOGY Suppose you needed to remove Answers will vary. The following steps are used by paleontologists. First the rock is a fossil bone from a chunk of placed in layers of cloth soaked in wet rock. List the steps you would plaster in order to protect fragile fossils. follow to complete the task. Later this jacket is removed, usually by soaking, sawing, and slicing. Chemcial solutions are applied to harden the bone. After that, power tools, such as pneumatic chisels and dental drills with diamond cutting wheels, are used to free the bone from the rock. Sometimes acid baths are used to dissolve the rock. On which continent do you Human beings are a member of a scientific family called hominids. The oldest known think the oldest-known close remains of a hominid were found in the relatives of modern human 1970s in Hadar, Ethiopia, in Africa. This ancestors lived? How long ago hominid stood erect and had a skeleton and teeth much like ours. The remains, and where did the ancestors of believed to be between 3 million and 3.6 modern humans first live? million years old, are of an adult female Australopiethecus afarensis, whom scientists call Lucy. Since clothing does not leave a Other items that are more durable than clothes give anthropologists clues about fossil record, how do anthropol- how Stone Age people dressed. ogists know anything about the Archaeologists have found tools such as clothing of Stone Age people? knives, arrowheads, and hatchets which let them know what kinds of animals were hunted and how their carcasses were used. Fossilized sewing needles, by their size and strength, suggest what materials might have been used. Knowledge of local vegetation indicates what plant and animal materials might have been available for making clothes. Knowledge of climate gives clues about how much clothing would have been necessary. Most anthropologists agree that The oldest human ancestors discovered so far lived in Tanzania and Ethiopia in the first ancestors of modern Africa. They were from a group that humans lived in Africa and that, anthropologists call Australopithecus much later, modern humans afarensis. Their remains are about 3 million years old. None of the human probably migrated from Asia to remains found in the Americas are that old. North America. What evidence The fossil record suggests that various might support these animals migrated across a land or ice bridge between Siberia and Alaska, and conclusions? that humans followed these animals to the Americas on hunting expeditions more than 10,000 yeas ago. Trilobites are prehistoric crab- A fossil that contains the imprint of a trilobite is probably about 450 million Like animals that lived on earth years old. Usually fossils show only about 450 million years ago. skeletons of the living things whose bodies What can be inferred about a are imprinted on them. However, some fossils found in New York State show the fossil that contains the imprint trilobite’s soft body parts, such as its of a trilobite? delicate antennae. These trilobite fossils are preserved in a mineral known as pyrite, or fool’s gold. The trilobites found at this site lived in water 100 to 200 meters (300 to 600 feet) deep. When mud suddenly covered this ocean floor, it covered these animals too, and they were preserved as fossils. The fossil of a trilobite from this area looks like a gold bug. Well-preserved bodies thou- By studying these remains, anthropologists learn what these people ate, the kinds of sands of years old have been work they did, and the clothes and jewelry found in peat bogs in northern they wore. Anthropologists have also made Europe. What can anthropolo- hypotheses about their customs and beliefs. Over the years, approximately 2,000 well- gists learn by studying these preserved bodies have been recovered from remains. peat bogs in places ranging from Ireland and Russia. Most of these bodies are hundreds or thousands of years old. They shed light on the lives of Iron Age people, who lived from about 1000 B.C. to about A.D. 100. How can a scientist tell how old Scientists identify any animal bones found with a fossil. Different animals were alive a fossil is? during different periods, so by identifying animal bones scientists can assign the fossil to a certain time period. Sometimes scientists analyze chemicals in rocks to tell when a fossil was formed in them. For example, some rocks contain a lot of potassium. A small amount of potassium gradually changes into argon. Since scientists know how long this process takes, they can make estimates based on the amount of argon in the rock. Sometimes scientists find dino- Sometimes fossils are found by accident on construction projects. Heavy earth-moving saur fossils on archaeological equipment may uncover them. Fossils may digs. Can you think of ways that also be found by hikers or amateur people who are not scientists naturalists. Whenever amateurs find fossils, they should contact scientists so can accidentally discover that the fossils, they should contact fossils? scientists so that the fossils can be removed and transported carefully. The Great Rift Valley in eastern A valley is a good site for finding fossils because humans and animals gather at Africa is an ideal site for finding sources of water. The Great Rift Valley in fossils of prehistoric humans eastern Africa gradually formed over a and animals. Why would a period of 20 million years. As it deepened, rivers and streams helped erode soil from valley be a good site for finding banks and beds. The eroded soil was fossils? deposited in the valley, forming layer upon layer of sedimentary rock. Bones were buried and preserved in this process. In some places in the Rift Valley, the layers of sediment are hundreds of meters thick, containing myriad clues about prehistoric life. If you want to find fossils, what Fossils are often contained in sedimentary rock, such as limestone and shale. Sedi- kind of rock should you look mentary rock usually forms from layers of for? debris that settle in the beds of bodies of water. Limestone, for instance, is made from fragments of shells and skeletons of tiny sea creatures. Shale is compacted flakes of clay. Under pressure for a long time, these layers become rock. If a plant or an animal was buried in the debris, the rock might contain a fossil, or an imprint, of the organism. Some dinosaurs may have cared Paleontologists have found fossils of a nesting colony of Maiasaura that include for their young after they were about 20 eggs in a mud nest. The fossilized hatched. What evidence would bones of adult Maiasaura were found show that dinosaurs nurtured among the bones of the young Maiasaura. Scientists think that the female Maiasaura their young? Dinosaur protected her young from predators and brought her babies food. Maiasaura means ―mother lizard.‖ What modern-day animal do Crocodiles are the nearest living relatives of dinosaurs. The thecodont (socket- you think is most closely related toothed reptile) was a crocodilelike to the dinosaurs? creature living many millions of years ago that began running on land. Over million of years, some thecodonts became smaller and faster. Eventually they began walking on two legs and evolved into Staurikosaurus, One of the first dinosaurs. Birds are also descendants of dinosaurs. PHYSICS Why don’t the wings of Engines provide the power to move air- Planes forward and lift them off the airplanes have to flap like the ground. Birds must beat their wings against wings of birds? the air to create the power to move forward. Special feathers in birds’ wings and tails push against the air to provide power to lift them. HANDS-ON ACTIVITY: Challenge groups of students to design a paper airplane that will travel the greatest distance possible when launched. Then hold an ―Airplane Race‖ to identify the design best suited for flight. How is sunlight both harmful Ultraviolet radiation, which comes from the sun, causes sunburn, skin cancer, and and beneficial? eye problems like cataracts. Since the ozone layer of the atmosphere (which prevents too much ultraviolet radiation from reaching earth) is being reduced by pollution, it is more important now than it was many years ago not to get too much sun. However, sunlight is made up of many kinds of radiation. Some rays are beneficial—sunlight is what warms and lights earth’s surface. Sunlight is important for photosynthesis, a process whereby plants are nourished and through which they produce the oxygen we use. Car brakes work as a result of Friction between dry objects causes bits of each object to wear away. Even though pressure between two rubber they are made of hard rubber, brake pads brake pads on each wheel. Why eventually wear thin and start to squeak. A do you think brake pads car owner should have a mechanic inspect the car regularly to make sure that gradually wear out? important safety features such as brakes are functioning properly. HANDS-ON ACTIVITY: Have students ―experience‖ friction by rubbing their hands together rapidly and then placing their hands on their faces. They will feel the heat energy generated by the friction of their hands. This same force, friction, is what causes brake pads to wear out. Extend the activity through a discussion of how one should properly maintain the brakes of a bicycle to ensure safe riding. Gravity is one of the forces that Although people don’t think of themselves as being electric, electricity is part of what affects you. Another force is holds the body together. This electricity electricity. How does this affect comes from the electromagnetic force that you? surrounds us, and some of its wavelengths go right through us. Electromagnetism plays a part in keeping atoms together. The electromagnetic spectrum has different wavelengths. At one end of the spectrum are shortwaves and at the other, gamma rays. When scientists began to experi- The units of measure that already existed were simply not tiny enough to describe ment with atomic particles, they atomic particles. Therefore, the fermi, invented a new unit of measure named after the Italian scientist Enrico called the fermi. Why? Fermi, was introduced. One-thousandth of a micron equals one million fermis, which means that one fermi equals one-millionth of a millimicron. A king suspects his goldsmith Archimedes, a noted scientist in the ancient Greek city of Syracuse, was given this task. cheated him by mixing silver At first, he was stumped. Then, according into his gold crown. He com- to legend, he stepped into a full bathtub, missions you to find out if he is and it overflowed. He cried, ―Eureka,‖ which means ―I found it‖ in Greek. correct. How can you do this? Archimedes weighed the crown and an Hint: Gold is heavier than silver. equal mass of pure gold. He placed each in an equal amount of water and compared the amount of water that each displaced. Because gold is heavier than silver, it takes up less space than an equal mass of silver. A crown with silver in it will displace more water than a crown made of pure gold. Volume is the amount of space Objects with the same volume have different weights if they have different that a substance occupies. Why densities. The heavier the molecules in a is it that equal volumes of substance and the more closely packed different substances can have they are, the greater the density. A sample of gold, for example, weighs more than different weights? Metal or eve seven times as much as a sample of aluminum of the same volume. HANDS-ON ACTIVITY: Use a ruler, scale, container, and some rocks to illustrate the difference between volume and weight. Have students measure the container and calculate its volume. Then have students weigh the empty container. Fill the container with rocks and have students again calculate its volume and measure its weight. Students will see that the weight of the container changed, but its volume remains the same! How are a laser beam and a Both kinds of light are made up of tiny energy particles called photons. Photons flashlight beam alike and vibrate in waves to produce light. In a different? flashlight beam, the photons spread apart, which is why a beam of light gets wider and eventually fades away as it gets farther from the flashlight. A laser concentrates a beam of light so that the photons are all in a single straight line, vibrating in the same way. This makes the laser beam very strong and able to travel a long distance without fading. A laser is so strong that it can be used to cut metal or even diamonds. Lasers are also used for some kinds of medical surgery. Why does ice, which is solid When water molecules form a solid, they are arranged in a fixed pattern with more water, float in liquid water? space between them than they had in their liquid state. This space causes water to have a greater volume with the same weight, and thus less density, in the solid State. This lower density is why ice cubes take up more space in ice cube trays than the water did, and why pipes may burst when the water in them freezes. HANDS-ON ACTIVITY: Demonstrate the principles described in this question by filling an ice cube tray with a mixture of food coloring and tap water. Be sure to fill each compartment to the top. Freeze cubes overnight. Display a solid cube to the class and have them note any change in appearance. Than place 2 colored cubes in a pan of tap water. Students will observe the colored cubes float and then begin to melt. How does a Styrofoam cooler The Styrofoam, with its trapped bubbles of air, acts as an insulator, or barrier, keeping keep food cold? the molecules of hot air outside the container from hitting the molecules of cold food inside the container. Another good heat insulator is the bonosilicate of a thermos bottle, which keeps liquids hot or cold by preventing heat from passing in or out of the bottle. Some poor insulators are porous materials like paper, pine and other soft woods, and cotton cloth. HANDS-ON ACTIVITIES: Challenge groups of students to create a ―homemade cooler.‖ Student groups should use household materials to make their inventions. Then test the insulating ability of their inventions by placing an ice cube in each and checking periodically. How are a nutcracker, a seesaw, All of them are levers. A lever is a bar that turns about a fixed point, giving its user and a rake alike? more power to lift, squeeze, or push something. A lever is a machine, and a machine is anything that can make work easier or faster. That is, a machine can help you move something from one place to another in less time or with less effort than it would otherwise take you. The simplest machines, are levers, screws, inclined planes, wheels and axles, pulleys, and wedges. Why do you seem to see pools These ―puddles‖ on hot highways are reflections of the sky caused by bent rays of water on a highway on hot of light. When the sun heats the road, the summer days? layer of sir just above he road gets hotter and thinner than the air higher up. As light from the sun passes from the cooler air through this layer of hotter air, the rays of light are bent, or distorted, so that a reflection of the sky appears on the road. This reflection looks like water. HANDS-ON ACTIVITIES: Use a clear glass of water and a pencil to show your students another example of the bending of light rays. Put the pencil in the water. Have the students observe the side of the glass from eye level. The disjointed appearance of the pencil is caused by the bending of light rays as light travels through different mediums. If you drop a steel spoon into a A ship, which has hollow places within its steel structure, floats because it displaces bucket of water, the spoon sinks enough water relative to its volume, or size to the bottom. How can a ship to hold it up. If you drop something into made of steel float? water, the object displaces, or pushes aside, a certain amount of water; The buoyancy (the ability of an object to float) is a force equal to the mass of the displaced water. The more water the object displaces relative to its volume, the more force the displaced water exerts to keep the object afloat. A spoon doesn’t float because it doesn’t displace enough water. HANDS-ON ACTIVITIES: You can demonstrate this concept, known as Archimedes Principle, using a plastic container, some rocks, a ruler, and a bucket or sink filled with water. Have students measure the area of the container Place the empty container in the water and observe. Then, fill the container with rocks and measure its area. Place the filled container in the water. Students will see that changes to the weight, not area, of the container caused it to sink. Why does your dentist drape a The heavy lead apron draped over you acts like an X-ray shield. The lead absorbs the heavy lead apron across you X-rays, protecting your body from possible before X-raying your teeth? injury. X-rays can damage the cells of living things. When a cell reproduces, each gene, or hereditary message, is reproduced. For an accurate reproduction to have occurred, all the atoms of the new gene have to be in the same order as the original gene. Atoms vibrate all the time, but radiation from X-rays makes atoms vibrate so much that the chances of a ―mistake‖ occurring when the genes divide increase. PSYCHOLOGY Draw two conclusions from this Answers will vary but may include the following: (1) Age is associated with graph. REM sleep, or rapid eye changes in patterns of sleep. (2) The movement sleep, is dream sleep, amount of REM sleep decreases with age. during which the eyes move HANDS-ON ACTIVITES: You may extend this examination of sleep patterns rapidly. by having each student survey five people Regarding the average time spent sleeping during a 24-hour period. When recording responses, students should note the age of each participant. Compile all the data as a class activity. Identify any trends that exist in the data. Does a relationship exist between the amount of sleep a person needs and his/her age? For the most part, the left half of Psychologists and physicians have been able to examine persons who have suffered the brain controls the right half damage to specific parts of their brains. For of the body, and the right half of instance, when a person has a blood clot in the brain controls the left half of the brain, a part of the brain may stop functioning because of insufficient blood the body. How do you think this flow. This event is called a stroke. Many connection was discovered? stroke victims lose the use of a hand or arm, or even an entire side of the body. Autopsies of stroke victims reveal damage to the side of the brain opposite the disabled part of the body. Jane likes to study for a big test Joaquin’s method will more likely produce a higher test grade. Psychologists have by ―cramming‖ the night before. found that he best way to learn something Joaquin prefers to spend a little is to study it repeatedly. They have also time studying every evening found that it is important to study actively. Instead of just reading the information, try during the week before the test. repeating it out loud and restating it in your Who do you think has the better own words. Rehearse the information as method, and why? often as possible, form associations with things you already know. One way to retain ideas is by linking the information to pictures in your mind. The best time to study is shortly before going to sleep. HANDS-ON ACTIVITIES: Encourage volunteers to create a series of associations that students could use to prepare for an upcoming test. Volunteers should share their ―study aids‖ with the class. Scientists do not know why Answers will vary. The following is an example. Ask several students to refrain people dream. Sigmund Freud from doing something they enjoy for a suggested that people dream in week and to record their dreams each order to have experiences denied night. For example, students might refrain from eating dessert for a week. When you them when awake. Design an review the records of their dreams, you experiment to test Freud’s would check to see if people dreamed theory. about eating dessert. HANDS-ON ACTIVITIES: Encourage students to conduct their experiments and share their findings with the class. Poll the experimenters to determine whether their data supported or contradicted Freud’s theory. How can someone tell when you When you are dreaming, your eyes move back and forth under the eyelids, This are dreaming, and why is dream dream sleep is called rapid eye movement sleep important? (REM) sleep. REM sleep seems to be a key period of sleep. In controlled experiments, scientists have deprived people of REM sleep by waking them every time their eyes began to move under the eyelids. Extreme anxiety results when people are deprived of REM sleep. A chimpanzee named Washoe Answers will vary but may include the following: You could offer food, show the was taught to use sign language. chimp how to make the sign, then give the How might you teach a chim- chimp food in return for making the sign. anzee to sign ―thumbs up‖? You could wait until you see the chimp put its thumb up, then praise the chimp or feed it. You could put your thumbs up just before you give the chimp food then put the chimp’s thumbs up, then reward the chimp with food. All of these methods would help the chimp to associate making the sign and receiving food as a reward. How can you tell if someone People who can be hypnotized have a can be hypnotized? characteristic that is called postural sway. When these people stand with their eyes closed, they begin to sway. Most people, but not everyone, can be hypnotized. Some people can be hypnotized more easily than others. Try this experiment: Have several of your classmates stand with their eyes closed, and see if you can tell which of them can be hypnotized. HANDS-ON ACTIVITY: Challenge the class to determine whether the percent of people who demonstrate postural sway is consistent for any group. Have them conduct the experiment within your class and record the results. Then have them repeat the experiment on another class of students and compare their findings. Psychologists have found that Answers will vary but may include the following: You can outline or summarize students who actively work with what you have read or heard, underlining information they hear or read the most important points or saying them retain it better than those who aloud. This process involves deciding what is most important in the material you are memorize through repetition. studying. You can take notes as you study How can you use this informa- a textbook. You can also leave room in the ion to study more effectively? margins of your notes for writing comments and questions. HANDS-ON ACTIVITY: Encourage volunteers to apply some of these study tips to the preparation for an upcoming test. Volunteers should present their methods to the class. If possible, use class average to determine whether these new study methods improved class performance. TECHNOLOGY Why is there a black bar code on The black bar code on boxes, jars, books, magazines, and other products is a com- some of the packages you buy? puter-readable symbol known as the Universal Product Code (UPC). Using the scanner, or electronic eye, at the cashier’s station, a computer reads the black bars to price and records the items you buy. The first five digits of the UPC tell the computer who manufactured the item. The second five digits identify the product, including characteristics such as size and flavor. Once the computer has this information, it matches the price to the product. Prices of products are stored in the computer’s memory. The information in the UPC enables the supermarket cash register to pint out words or abbreviations identifying what you’ve brought. The earliest airplane wings were Most planes today have a single wing on each side because wings are now made of made of linen stretched over a metal. A metal wing has a great advantage wooden frame. Most airplanes over one made of linen stretched over a then had two winds on each wooden frame; namely, a metal wing can be large in size and still strong enough to side. Why do most planes today hold together in flight. A large wing made have only one wing on each of linen stretched over wood, on the other side? hand, is not strong enough to hold together in flight. The earliest planes, therefore, had to have two of these wings on each side in order to fly. Why is the freezer usually at the The compressor is the warmest part of a refrigerator, and the freezer is the coldest top of a refrigerator instead of at part, so it makes seems to have the freezer the bottom? and the compressor far from one another. This arrangement slows down the process of heat transfer, saving the most energy. In the 1950s, almost half the refrigerators made had freezers at the bottom. Manu- facturers promoted this as a refreshing New design. Today we are more concerned with energy efficiency than we were in the 1950s. What is the difference between a Compact-disc players are digital devices, like computers, and record players are not. compact-disc player and a When a compact disc passes over an record player? optical readout system, a laser reads the auditory information on the disc. A record player produces sound differently. A needle contacts the record, which has contours in its groove walls that correspond to the frequency and loudness of what was recorded. When the record player’s needle rests on these grooves, it vibrates. This causes the cartridge to produce an electrical signal which is translated into sound. An assembly line is an efficient Answers will vary. An example follows. A child-sized grocery cashier station is being way of producing things that produced. On an assembly line at one many people can buy. Each step workstation, workers put together the in the process of manufacture is plastic counter. At another, the conveyor belt for the counter is attached. At another, assigned a specific place on the the cash register body is assembled. At assembly line, and each product another, the mechanism that allows the is the same as all the rest. See if cash register drawer to pop out is inserted. you can design an assembly line HANDS-ON ACTIVITIES: Have a group of students use a classmate’s for making a new toy. Make a assembly line design to actually create a chart to show the step completed toy. Discuss the advantages and disadvantages of this method of producing at each place on the assembly a product. line. At one time, all television The major urban centers and rural mountainous areas had the worst reception signals were broadcast through when the signal was broadcast rather than the air and received through transmitted through cables. Buildings and antennae at the homes of tele- mountains are nearly impenetrable barriers for broadcast television signals. Thus cable vision owners. What kinds of television companies provided many urban communities had the poorest and mountainous areas with the first good television reception at that time? television reception they had ever had. The transistor is a tiny device Because transistors are so tiny, they made the development of microprocessors and that controls electronic signals. microcomputers possible. Thousands of What do transistors have to do transistors can be arranged on silicon chips. with computers? These and other miniature components are built in layers to form complex patterns of connections necessary to a computer. The transistor was first developed during the 1940s. Computer-aided design (CAD) Answers will vary but may include the following: you can use CAD in designing is a method of designing the engine, the interior, the instrument products on a computer screen. panel, or the body of the car. CAD tech- How would you use CAD to niques can move shapes around on the screen, change colors, and change design a new car? Make a sketch dimensions precisely. Car manufacturers of your new automobile. use CAD to analyze an automobile’s design before it goes into actual production. HANDS-ON ACTIVITIES: Encourage students to make a sketch or model of their new car designs. Have volunteers present their creations to the class and explain the benefits of their inventions. Supercomputers are the fastest Answers will vary but may include the following: to help analysts understand the and most powerful computers of effects of different chemicals in car our time. How might you use a exhaust, to help doctors understand how supercomputer? Try making a heart attacks occur, or to help astronomers study distant galaxies. NASA uses super- sketch of an invention you could Computers to process weather information, create using a supercomputer. to study the atmosphere on Mars, and to design spacecraft. Geologists use supercomputers to find oil and gas deposits. Oceanographers use them to analyze the movement of ocean currents. HANDS-ON ACTIVITIES: Have volunteers share their sketches with the class. Classmates should consider whether any negative side effects are possible with each invention presented. This will develop student understanding that most technolog- ical advances have hidden harmful effects. For example the automobile is a major contributor to air pollution while revolutionizing transportation. An ultrasound procedure shows The doctor would use ultrasound to check the size of the heart or liver. An ultrasound the soft organs and tissues inside Would also show the position of a fetus the body. An X-ray shows the within the mother’s uterus. An X-ray bones and hard tissues. Tell would show a broken bone or any decay in the teeth. HANDS-ON ACTIVITY: which procedure a doctor would Ask student volunteers to bring any X-rays use in these examinations: they have had taken to class. Allow each Checking for a broken bone student to display the X-ray to the class and describe its original purpose. (Or, you Checking the size of the heart may borrow old films showing broken or liver bones from a local physician or hospital.) Observing the position of an unborn child Looking the cavities in teeth Why do men’s and boys’ One of the reasons that women’s bikes do not have crossbars is that women used to bicycles have crossbars on them, wear skirts more often than they do today. whereas women’s and girls’ The crossbar makes mounting and bicycles do not? dismounting difficult when one is wearing a skirt. Today, girls and women who bicycle competitively ride bikes with a crossbar. The crossbar adds extra strength to the bicycle because it forms a triangular frame, which is the best shape for supporting weight. Architect and scientist Buckminster Fuller suggested that buildings should be made out of triangular pieces joined together. He called the buildings e designed geodesic domes. Does computer technology play Yes, videos and computers work in much the same way, and computers can produce a part in making a video game, exciting video images. When video and if so, how? manufacturers use a video camera to make images for a game, the camera sends an electronic signal to a video recorder. The technician making the game can’t see the pictures on the film. Instead, the video recorder processes the electronic information to create images that the technician sees when the video player is activated. Microprocessors, which are tiny To estimate how many computers you see or use, make a list of things that involve yet powerful computers pushing buttons to program something or contained on a single silicon to receive information. Chances are, you chip, are all around you. How see and use computers a lot more than you think. Microprocessors are used in auto- many uses of these computers mobiles, cameras, copying machines, audio can you name? equipment, microwave ovens, auto- matic teller machines, telephones and answering machines, cash registers, library circulation equipment, video games, VCR’s, and televisions, not to mention personal computers at home, at school, or in a library. How is a jet plane like an A jet engine moves a plane in the same way that escaping air moves a balloon inflated balloon that you’ve just when you blow it up and let it go. As a jet let go? engine burns fuel, the heat and pressure force compressed gases out the back of the engine with a force equal to that of the combustion occurring in the engine. The force of the gases pushing back from the engines overpowers gravity exerted on the jet plane, just as the force of air blowing out overpowers gravity exerted on the balloon. HANDS-ON ACTIVITY: Use a number of different sized balloons and a measuring tape to show students that every action has an equal but opposite reaction. Have volunteers blow up the balloons to capacity. Then have each student stand on a ―starting line‖ and release their balloon. (Students should be directed to hold their balloon in a horizontal position with the opening pointed towards the body.) Measure the distance each balloon travels. Students will see a direct correlation between the amount of air released and movement of a balloon.