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AHA! Lesson Plan – Crazy Chemistry
1
Crazy Chemistry Lesson Plan
Objectives
The scientists will:
• Observe the separation of colors in ink.
• Learn about water molecules, cohesion, and surface tension.
• Determine the difference between two types of packing peanuts.
• Create a chemical reaction within a test tube that will cause a balloon to inflate.
• Create a chemical reaction that will result in lemon suds soap.
• Experience how the sense of taste is related to the sense of smell.
Materials
• Green and black water-soluble pens • Baking soda
• Coffee filters • Spoon and/or Funnel
• Saucer (or Styrofoam plates) • White vinegar
• Paper clips • Balloon
• Test tube • Lemon or lemon juice
• Test tube rack • Plastic cups
• Water • Liquid soap (Ivory or Dawn)
• Styrofoam packing peanuts • Paper towels
• Cornstarch packing peanuts • Life Savers or other flavored candies
Procedures
1) Introduce the topic of Chemical Reactions - a process in which one or more substances
are changed into others.
2) Follow Procedures for “Rainbow Effect.” Ask the children to guess (hypothesize) what is going
to happen. Set the plates aside and come back to them at end of program.
3) Follow instructions for “Over-Filled Tube.” Ask children to guess how many paper clips it will
take to make the water rise. As you surpass their guesses, let them pick a new number. Once
the water spills over the edge, explain what happened by defining cohesion and surface
tension. (See Over-Filled Tube: What’s Goin’ On?)
4) Follow instructions for “Packing Peanut Puzzle.” Children will observe what happens to each
of the packing peanuts. Explain the chemical reaction of the cornstarch dissolving in water.
5) Follow instructions for “Balloon Inflator.” Ask the children what is going to happen. (nothing?
balloon blows up a little? balloon blows up a lot? balloon explodes?)
6) Follow the procedures for “Lemon Suds.” This time the children will see a chemical reaction
between the baking soda and citric acid (lemon juice). At the end of this experiment, have the
children clean their stations with the lemon-scented cleaner they have created.
7) Return to the coffee filters and saucers. There should be trails of blue, yellow, and red from
the black mark, and trails of blue and yellow from the green mark. The ink is dissolving; the
AHA! Lesson Plan – Crazy Chemistry
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water is carrying the pigments along at different rates, depending on the size of the pigment
molecules and on how strongly the pigment is attracted to the paper. This technique of
separating pigments/colors is called chromatography.
8) Talk about the tongue and its four types of receptors – sour, sweet, salty, bitter. Explain how
taste is related to sense of smell. Talk about how when you are sick with a cold and stuffed up
nose, sometimes food does not taste right. Follow the steps for “Your Sense of Taste.” Have
the children guess what flavor candy they were given. It’s harder than they think!
Conclusion
Which experiment did you enjoy the most today? What did you like about it? Try making soap
suds at home and help clean up the kitchen with your lemony creation!
AHA! Lesson Plan – Crazy Chemistry
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Rainbow Effect
Materials
• Green water-soluble pen/marker
• Black water-soluble pen/marker
• Coffee filter
• Saucer
• Paper Clip
Procedures
1) Fold the coffee filter in half.
2) Fold it in half again.
3) Make a dark green mark about one inch from the rounded edge of the
folded filter.
4) Make a second mark with the black marker about one inch from the
rounded edge. The two marks are not to touch each other, but need to
be on the same side.
5) Secure the edge of the filter with the paper clip so that a cone is
formed.
6) Fill the saucer with water.
7) Place the rounded edge of the cone in the water.
8) Allow the paper to stand undisturbed for one hour.
Results
It takes about one hour for the colors to separate. A trail of blue, yellow, and red
is seen from the black mark, and the green mark produces a trail of blue and
yellow.
Why?
Black and green are combinations of other colors. As the water rises in the
paper, the ink dissolves in it. Some of the colors rise to different heights
depending on the solubility of the chemicals producing the color. The more
soluble chemicals move with the water to the top of the paper.
Source
VanCleave, Janice Pratt. Chemistry for every kid: 101 easy experiments that
really work. New York: Wiley, 1989, pp 154-155.
AHA! Lesson Plan – Crazy Chemistry
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Over-Filled Tube
Equipment
• Paper clips
• Super Tube™ and rack
• Water
Try This!
1) Set the Super Tube in the support rack. Completely fill the tube with water.
The water should rise slightly above the rim. If needed, add more water.
Looks pretty full, right?
2) How many paper clips do you think you could add to the tube without
making the water overflow?
3) Now, carefully add paper clips to the water, one at a time, until the water
spills over the tube’s edge. How many did you add? If you added more
than you thought you could, congratulations!
What’s Goin’ On?
Water molecules like to hang onto each other, sort of like magnets. This force is
called cohesion. As more paper clips are added, the molecules get stretched
until they can’t hold on anymore. They break apart, and the water spills over the
tube’s edge.
The mound of water that appears over the top of the tube is caused by surface
tension. This is the name given to the cohesion of water molecules on the
surface of water. (“Linked” water molecules also help bugs, such as water
striders, walk across the water in ponds without sinking to the bottom. The
pressure their weight puts on the water is not strong enough to break the surface
tension, so they stay afloat.)
Eventually, the mound of water is weakened by gravity and air pressure, and the
surface tension breaks. Water runs down the outside of the tube. You may want
to try this experiment again, but this time add a drop of liquid soap to the test
tube. (Soap molecules can slip in between water molecules.) How do you think
this well affect your results?
Source
Super-Tube Science ™: Amazing Air & Water. Greensboro, NC: Wild Goose
Company, 2005, pp. 11-12.
AHA! Lesson Plan – Crazy Chemistry
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Packing Peanut Puzzle
Equipment
• 2 Super Tubes™ with rack
• Foam packing peanuts (both kinds)
• Magnifying lens
• Water
Try This! Part 1
1) Take a closer look at each type of “peanut.” Do they look different? Gently
squeeze both peanuts. Do they feel different from each other? Break them
apart. How would you describe the texture?
2) Place two Super Tubes in the support rack. Pour water into each tube just
up to the 40 mL mark.
3) Drop one foam packing “peanut” into the first tube and place one of the
other type of packing “peanuts” into the second tube.
4) Check out what happens to the “foam peanut” in each tube.
Try This! Part 2
1) Dissolve a couple of the cornstarch peanuts in water.
2) Now spread the mixture on paper. Can you use it to hold pieces of paper
together? Who needs school glue!
Explanation
The packing “peanuts” are made out of different materials. The one that
dissolved is made from cornstarch, a material found in corn that is
sometimes used to thicken foods. Sine it dissolves in plain water, it is not
harmful for the environment when thrown away. This means that if you
trash the packaging for the birthday gift that was sent to you, the
cornstarch packing “peanuts” will dissolve in the landfill when the soil is
wet. The other type of “peanut” is made from polystyrene, which is a kind
of plastic foam. Those peanuts don’t dissolve in water – so it’s better to
reuse or recycle them and keep them out of the trash!
Source
Super-Tube Science ™: Discover Chemistry. Greensboro, NC: Wild Goose
Company, 2005, pp. 20-21.
AHA! Lesson Plan – Crazy Chemistry
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Balloon Inflator
Equipment
• Balloon
• Super Tubes™ and rack
• Baking soda – or sodium bicarbonate
• Spoon
• White vinegar
Try This!
1) Place a Super Tube in the support rack. Add vinegar up to the 10 mL
mark.
2) Put 1 tsp. (13 mL) of baking soda (sodium bicarbonate) into the balloon.
(Use a small funnel to make this step a lot easier!)
3) Twist the balloon so the baking soda is trapped inside at the bottom of the
balloon. Then stretch the mouth of the balloon over the opening of the
tube. Be sure to keep the balloon twisted shut!
4) Hold the balloon straight up over the top of the tube. Carefully untwist the
balloon so that the baking soda will fall into the vinegar.
5) Stand back and watch what happens!
What’s Goin’ On?
The setup is a closed system, which means everything is trapped in the
space inside the Super Tube and the balloon. When baking soda (sodium
bicarbonate) and vinegar (acetic acid) are mixed together, a gas called
carbon dioxide is produced. In fact, they can make tons of carbon dioxide
when mixed together. Those gas molecules are very active; they’re busy
zooming around and pushing on things. One of the things the molecules
push on is the balloon, so it inflates!
Source
Super-Tube Science ™: Discover Chemistry. Greensboro, NC: Wild Goose
Company, 2005, pp. 29-30.
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