Physical Science A study of matter and energy What will we study this year? Chemistry Properties Elements,Mixtures, Compounds Atoms, Molecules and the Periodic Table Physics Forces and Motion Energy- Waves, Sound and Light Electricity and Magnetism Tools of a Scientist Observing Interpreting Data Predicting Inferring Classifying Communicating Measuring Let’s Review How do we go about finding a solution to a problem? Scientific Method Observation Analyze Results Ask a question Organize data in chart, graph, drawing Form a hypothesis Summarize findings Design an experiment Draw Conclusion to test hypothesis Make inferences (possible Variables (controls, explanations why, reasons manipulated variable, for results) responding variable) Materials Communicate Results Procedure Repeat Let’s Review What are the basic components of every investigation? Controls Thingsthat never change in an experiment Why do we need them? Variables- think DRY MIX Manipulated (Independent) X axis Variable changed in an experiment How many can you have in each experiment? (Dependent) Responding Y axis Variable that responds to the change Variable that depends on the other variable Types of Set Ups Control set up- experiment without the manipulated/independent variable Experimental set up- experiment with the manipulated/independent variable Sample Scenarios Determine what question is being tested. Identify the controls in the scenario. Identify the manipulated/independent variable. Identify the responding/dependent changeable. The students sat still for 5 minutes then took their pulse for 30 seconds, walked around the room for one minute and took their pulse for 30 seconds, exercised for one minute and took their pulse again. They recorded the class data, averaged and graphed the results. The researchers placed 1 gram of a chloride compound in a liter container full of water, marked A. Then they placed 2 grams in one liter of water marked B and 3 grams in a one liter container marked C. The temperature was measured after the chloride compound had been mixed for 30 seconds. A net was set up to catch insects. The insects were removed, classified and counted by groups every 3 hours for 5 days. The number and kind of insects were compared by the time of day they were collected. Experimental Design Determine how to set up an experiment to test each problem. What materials would you use? What is your procedure? Which brand of floor wax holds its shine the longest? What effects the growth of tomato plants? What is the effect of water temperature on the dissolving time of sugar crystals? Scientific Theory a unifying explanation for a broad range of hypotheses and observations that have been supported by testing. A theory can explain observations and predict future observations. Theories can be changed as new observations are made. Example: Atomic Theory Scientific Law A summary of many experimental results and observation. A law tells you how things work. Laws are not the same as theories because laws only tell you what happens not why it happens. The law tells you that you can expect the same thing to happen every time. Example: Newton’s Laws Let’s Review How do we measure our results? The SI system What is SI? Why do we use it? System International or International System of Units Metric System Decimal system (base 10, multiples of 10) Each unit is 10 times bigger or 10 times smaller than next unit Very precise and accurate Internationally used Basic Units Quantity Unit Symbol Instrument Length Meter M Metric ruler, meter stick, trundle wheel Volume Liter L Graduated Cylinder, LxWxH Mass Gram G Triple Beam Balance Weight Newton N Spring Scale Prefix Power of 10 Symbol Example kilo- 1000 (103) k kilogram (kg) hecto- 100 (102) h hectoliter (hL) deca- 10 (101) da decameter (dam) Basic unit 1 (100) --- Meter, Liter, Gram deci- 0.1 (10-1) d decigram (dg) centi- 0.01 (10-2) c centimeter (cm) milli- 0.001 (10-3) m milliliter (mL) Kids Kilo Have Hecto Dropped Deca Over Ones (meter, liter, Dead gram) Converting Deci Metrics Centi Milli Let’s Practice…. 4 kg = _____ g 3 km = _____ dam 400 mL = ______ L 3275 g = _______ kg What about really small things? Micro- millionths Nano- billionths Angstrom- 10 billionths Let’s Review What are some basic properties? Mass The amount of matter in an object Instrument-triple beam balance Basic Unit= the gram Weight A measure of attraction between 2 objects due to gravity Affected by mass and distance Mass Weight (direct relationship) Distance Weight (indirect relationship) Instrument- Spring Scale Unit- Newton If you eat too many fig newtons you will weigh a lot! Mass x 9.8 = weight in Newtons Weight ÷ 9.8 = mass in Grams Volume A measure of the amount of space an object takes up Regular object- L x W x H Irregular object- water displacement using graduated cylinder Volume (water displacement) Fill cyclinder with water Record volume of water (look below meniscus) Place object in water Record volume of water with solid submersed (look below meniscus) Subtract volume of water from the solid and water combined Record results in mL or cm3 of cc Volume Activities 10 cm x 10 cm x 10 cm = 1000 cm 1000 cm = 1000 ml Volumania p.9 Lab Book Mission Impossible Activity Examine an index card. Take note of its size and shape. Your mission is to fit yourself through the card. Brainstorm with a partner about possible ways to complete your mission keeping the following guidelines in mind: You can use scissors and you can fold the card but you cannot use staples, paper clips, tape , glue or anther other adhesive. Test your strategy and share your results with the class. Density Relationship between mass and volume the amount of mass per unit volume Mass ÷ Volume or M / V g/ml or g/cm3 or g/cc Density Take the mass of an object using a triple beam balance, take the volume of object by either water displacement or calculating L x W x H. Divide mass by volume to obtain the density of an object. Density of water = 1 g/ml If density > 1 , object sinks If density < 1, object floats Density Activities Marbles, sand, water Alcohol and water Orange in water Density column Chocolate Bar lab The Case of the Missing Crown Imagine that you are living in Europe in the Middle Ages. You have been summoned by King of your land to help in a very important matter. Someone has stolen the king’s solid gold crown. The king has issued a proclamation offering a reward of 500 gold coins for the safe return of his crown. The problem is that the king has received hundreds of crowns—and they all look exactly alike the missing crown. Your job as a brilliant scientist is to find out which crown is the real one. Crown # Mass (g) Volume (cm3) 1 1890 180 you collected Here is data486 2 180 3 1404 180 4 3474 180 5 2034 180 Density of common metals: Gold 19.3 g/cm3 Aluminum 2.7 g/cm3 Silver 10.5 g/cm3 Lead 11.3 g/cm3 Copper 9.0 g/cm3 Iron 7.8 g/cm3 1. What properties can you determine from this data? Why is this useful? 2. Based on this data do you think any of these crowns could be the real one? 3. Which of the crowns are fakes? Why? 4. Can you guess what fake crowns are made of? 5. How do you think the fake crowns were made to look like the real ones? What is a model? A representation of an object or system Examples: rocket, atom, weather map, solar system, cell, building Why Use Models? Help visualize information that your cannot see directly (ex: atom) Just the right size (ex: solar system, phases of the moon) Build scientific knowledge to: Test hypotheses (ex: build a model plane to test wind patterns) Illustrate theories (ex: atom model) Saves time and money (ex: car design for crash test) Lab Safety Lab Safety For your protection. Use common sense. Required for every lab. Lab Safety Contract. Lab Safety Symbols Safety First Can you find all of the safety violations in the following slide?