Sally Ride Festival

MLK Jr. Library, San Jose Meet at 9:30am for Set-up

Saturday, October 18, 2013 Run Booth 10:00am-1:00pm

“The Sweet Side of Chemistry: Candy!” Clean-up 1:00pm-1:30pm

Booth Protocols

1) Get Slimed!

· For this experiment, volunteers and kids have to wear safety goggles. Ask the children to wash their hands thoroughly after they leave the library area.

· Working over the secondary containment, pour 20mL of 4% polyvinyl alcohol solution into a 5oz. plastic cup

· Add food coloring drops if the child desires and stir using a craft stick

· Add 5mL 4% borax solution to the cup, and stir

· Have the child observe what happens

· Have the child remove the material from the cup and knead it in their hand—the material will become firm and lose some of its stickiness

· The child can take their cup with slime home in a sandwich baggie—let the parent know that it can stain clothing or furniture, and that it may become moldy after a few days and should be disposed of in the trash

· Slime is a non-Newtonian fluid that is a dilatant, that is, under stress, the material dilates or expands. Under low stress, the material will stretch and flow. Pulling sharply (high stress) will break the material. Polyvinyl alcohol is used as a thickener, stabilizer and binder in cosmetics, paper cloths, films, cements and mortars.

2) Mentos Chemical Mystery!

· For this experiment, volunteers and kids have to wear safety goggles. Remind the kids that they cannot eat during the experiment.

· Pour an inch of water into a clear, colorless cup. Repeat twice so that you have 3 cups of water.

· Add a few drops of Universal Indicator. If the water solution is slightly acidic this is because water exposed to air will have carbon dioxide leach into the water from the air, this forms carbonic acid.

· Have the child put a mint Mentos into one cup and swirl. Have them observe what happens to the solution. Show them the plain water cup as reference so that they can see the acid has been somewhat neutralized by the mint Mentos. So the mint Mentos candy must have a base on it.

· Have the child put the fruit Mentos into the last cup and swirl. Have them observe what happens to the solution and compare this to the other solutions.

· The mint Mentos candy must have a base on it.

· The fruit Mentos candy contains citric acid which makes it acidic, therefore making the solution more acidic.

3) Testing Sour Candies for Acidity

· For this experiment, volunteers and kids have to wear safety goggles. Remind the kids that they cannot eat during the experiment, but if they complete the experiment, they can take home a fun-pack of Sour Skittles.

· Have the child prepare three mini-cups of water. To one cup, add lemon juice. To one cup add ½ tsp baking soda.

· Add a few drops of Universal Indicator to the 3 solutions. Explain that the basic solution is blue and the acidic solution is red.

· Now the child can pour several mini-cups of water and add Universal Indicator to each.

· Have the child guess which candy is the most sour (acidic) and drop one of their choice of candy into a cup and observe.

· Have the child rank the candies in order of acidity.

4) Floating Letters

· Remind kids that they cannot eat during the experiment, but if they complete the experiment, they can take home a fun-pack of M&Ms.

· Have the child prepare two mini-cups of water (use warm water if possible).

· To one cup, the child can add 2-3 M&Ms and observe. In the other cup, have the child add 2-3 Skittles and observe.

· The letters on the M&M or Skittles do not dissolve in water and are adhered to the candy with an edible glue that dissolves in warm water. Since the letters are less dense than water, the letters peel off and float as the rest of the candy shell dissolves.

· The colored dyes of the candies will color the water. Objects that are red absorb most of the colors of visible light EXCEPT red, which is reflected to our eyes. Objects that are blue absorb most of the red and yellow colors of light, and reflect blue light to our eyes. If you mix the two, only violet light is reflected to our eyes and the water looks purple. Yellow objects absorb violet light, and blue objects absorb red and orange light, so the mixture of yellow water and blue water looks green, the only color in the visible light spectrum that bounces back to our eyes.

5) Eat Dirt!

· In one flower pot (labeled with inorganic elements & humus), pour soil on top to make it look like a real potted flower, then decorate with gummy worms. In the other flower pot (labeled with sugar molecules, vitamins, etc.), pour crushed Oreos on top to make it look like a real potted flower, then decorate with gummy worms

· Invite kids to “eat some dirt”, by asking them, based on the labels for the two “dirts” which kind of “dirt” they would be willing to eat.

· Discuss how soil contains inorganic elements, trace metals, humus (broken-down organic materials), phosphates and sulfates.

· Discuss how oreos contain sugar molecules, vitamins, flour additives, chocolate.

· If the child chooses the correct dirt to eat (the crushed oreos!), then reward them with their own Oreo snack to take home to eat!

6) PopRocks

· Pour a few inches of warm water into a clear, colorless cup.

· Have the child pour a few pop rocks into the cup and observe the reaction. They should hear cracking and popping and see tiny air bubbles rising as the candy dissolves.

· The secret ingredient of pop rocks in CO2(g) that is pumped into the candy when it’s still melted, trapping bubbles. As the sugar part of the rocks dissolves, the bubbles of carbon dioxide are released.

· Now you will demonstrate blowing up a balloon using the gas released during the dissolution of the PopRocks.

· Using a funnel, pour 1 package of PopRocks into a balloon.

· Carefully stretch the mouth of the balloon over an open bottle of Coke, taking care not to drop the enclosed candy into the open bottle.

· Once the balloon is securely on the bottle, shake the contents of the balloon into the soda and observe.

· Repeat the balloon experiment using Nerds and see if it works better than PopRocks.

· So what causes the balloon to inflate? The CO2(g) contained in the candy isn't enough to cause even the small amount of inflation you observe in the experiment. That's where the soda comes into play. The soda also contains pressurized CO2(g) (it's why we call soda a carbonated beverage). When the PopRocks are dropped into the soda, some CO2(g) is able to escape from the high fructose corn syrup of the soda and, because the CO2(g) has nowhere to go in the bottle, it rises into the balloon.

7) Boo Bubbles

· For this activity, do not let the children touch or handle the dry ice. Do not put bubbles in your mouth or attempt to breathe the fog.

· Fill the graduated cylinders with hot water (not boiling). Periodically drop pieces of dry ice into the cylinder to create the fog. Once the water cools down, the fog will slow, so you can replace the water with more warm water.

· Using the Boo Bubble kit, gently dip the end of the tube in the cup of soap. Boo Bubbles will survive on the gloves or towel, but not other surfaces.

· Dry ice is frozen Carbon Dioxide, or CO2, which is a gas under standard temperature and pressure conditions. The atmosphere contains about .035% of this gas. CO2 is a greenhouse gas, which means it absorbs light at infrared wavelengths. An increase in the concentration of this gas would, some scientists believe, cause an increase in the atmosphere's average temperature. The high concentration of CO2 in the atmosphere of the planet Venus is said to contribute to that planet's high average temperature.

· At normal atmospheric pressure on this planet, frozen CO2 doesn't melt into a liquid, but rather evaporates directly into its gaseous form. Hence the name dry ice. This process is called sublimation. All of the experiments below rely on this property of dry ice. 1 pound of dry ice, when it sublimates (turns to gas) will produce 250 liters of gas at atmospheric pressure, enough to fill 125 2-liter bottles. That's a lot of gas!

8) Pixi Stix Counting!

· Explain that it is possible to calculate the number of molecules of sugar in a jar of pixi sticks, using Avogadro’s number.

· Have the child guess how many pixi sticks are found in the jar.

· Help them to use the calculator to calculate how many molecules of sugar are in the jar.

·
Let them know the real number in the jar. If they guess within 50 sticks of the correct answer, give them a pixi stick to take home.