THE AMERICAN CHEMICAL SOCIETY CLEVELAND SECTION & NASA GLENN RESEARCH CENTER. Can you Grow and Shrink a Gummy?

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1 THE AMERICAN CHEMICAL SOCIETY CLEVELAND SECTION & NASA GLENN RESEARCH CENTER As part of the National Chemistry Week celebration (October 19-25, 2014) Ask students in Grades 9 through 12 to investigate: Can you Grow and Shrink a Gummy? Gummy Bears contain gelatin (just like Jell-O) and are made by heating gelatin with water, followed by cooling. The experiments below will allow you to investigate what happens when candy containing gelatin is added to water, with and without other materials. Materials: Follow the instructions below and answer the questions. 1 packet (4 oz) Gummy Bears (Original) Tap Water Distilled water Measuring spoons Measuring cups 13 small clear plastic cups Measuring Jug 1 cup size or larger Salt Baking Soda Clear pop, e.g. Sprite Clear diet pop, same brand as the sugared pop Paper Towels Plastic coffee stirrers Slotted spoon (that allows water to drain) Please do not eat any of the Gummy Bears used in the experiments! The experiment should be observed over a period of up to 24 hours! 1. Place the piece of Aluminum foil on a table or counter-top and cover with three layers of paper towels. National Chemistry Week Contest Page 1

2 2. Label 2 clear plastic cups, each with the letters W and DW. Label 4 clear plastic cups, each with the letters B1, B2, B3 and B4. Label 4 clear plastic cups, each with the letters S1, S2, S3 and S4. Label 3 clear plastic cups, each with the letters V, P, and DP. Place the cups in four rows as follows: Row 1: cups labeled W and DW Row 2: cups labeled V, P and DP Row 3: cups labeled B1, B2, B3 and B4 Row 4: cups labeled S1, S2, S3 and S4 3. Measure ¼ cup of tap water and pour it into the cup labeled W. Measure ¼ cup of distilled water and pour it into the cup labeled DW. Measure ¼ cup of vinegar and pour it into the cup labeled V. Measure ¼ cup of clear regular pop and pour it into the cup labeled P. Measure ¼ cup of clear diet pop and pour it into the cup labeled DP. 4. Pour tap water into the measuring jug up to the 1 cup mark. Add ¼ teaspoon baking soda. Stir well, with a clean coffee stirrer, until the solid is dissolved and you have a baking soda solution. This is your original baking soda solution. Measure ¼ cup of this original baking soda solution and add it to the cup labeled B1. labeled B2. Add ¼ teaspoon baking soda (solid) to the cup labeled B2 and stir labeled B3. Add ½ teaspoon baking soda (solid) to the cup labeled B3 and stir labeled B4. Add 1 teaspoon baking soda (solid) to the cup labeled B4 and stir 5. Thoroughly clean and dry the measuring jug. Pour tap water into the measuring jug up to the 1 cup mark. Add ¼ teaspoon salt. Stir well, with a National Chemistry Week Contest Page 2

3 clean coffee stirrer, until the solid is dissolved and you have a salt solution. This is your original salt solution. Measure 2 tablespoons of the original salt solution and add it to the cup labeled S1. Add 2 tablespoons clean tap water to the cup labeled S1 and mix well with a clean coffee stirrer. Measure ¼ cup of the original salt solution and add it to the cup labeled S2. Add ¼ teaspoon salt (solid) to the cup labeled S2 and stir with a clean coffee Measure ¼ cup of the original salt solution and add it to the cup labeled S3. Add ½ teaspoon salt (solid) to the cup labeled S3 and stir with a clean coffee Measure ¼ cup of the original salt solution and add it to the cup labeled S4. Add 1 teaspoon salt (solid) to the cup labeled S4 and stir with a clean coffee 6. Select 13 Gummy Bears (GB) that are all the same color, preferably Red, Green, or Orange. Select one more Gummy Bear of the same color to be GB 14 (the control) in the experiments. 7. Make a table like the one below to record your observations of the original gummy bear. Please use the s Scales (in 8. Below) for the conclusion of the experiment. Cup: W Size Color of Water Color of GB Before s After 24 hours Repeat this table for the other twelve cups. National Chemistry Week Contest Page 3

4 8. Use the rating scales below to record your observations for each category (e.g., size, bubbles, etc.) compared with GB 14: Size 0 GB completely dissolves 1 GB much smaller than GB 14 2 GB slightly smaller than GB 14 3 GB same size as GB 14 4 GB slightly larger than GB 14 5 GB much larger than GB 14 Color of Water 0 No color - same as tap water 1 Light Color 2 Medium Color 3 Dark Color Color of GB 0 Same color as GB 14 1 Slightly lighter than GB 14 2 Moderately Lighter than GB 14 3 Almost clear / much lighter than GB Add one of the thirteen selected Gummy Bears to each of the thirteen cups you prepared and placed in Rows 1, 2, 3, and 34, above. Place GB 14 on the paper towel next to the cup containing only tap water, i.e., labeled W. 10. After about 24 hours, use the slotted spoon to remove the Gummy Bears one by one from the cups (unless they have disappeared) and place them on the paper towels in front of the cups (in the same order that you placed the cups in Rows). Rinse the slotted spoon in tap water after you remove each GB out of each cup. Record your observations in your table. National Chemistry Week Contest Page 4

5 Questions: 1. How can you grow Gummy Bears to make them as large as possible in less than 12 hours? Can you explain why the Gummy Bears became larger in some cups? 2. How can you shrink Gummy Bears to make them disappear (or very small) in less than 12 hours? Can you explain why the Gummy Bears became smaller or disappeared in some cups? 3. Which solution (cup) kept the Gummy Bear shape the best after 6 hours so it still looked like GB 14 but was a different size or color? Can you explain why this cup worked best? 4. What are colligative properties? How may they have played a part in the results? 5. Why do cucumbers shrivel when they are turned into pickles? How does that involve colligative properties? 6. What would happen to a human red blood cell if the IV solution was made incorrectly? A concentration of sodium chloride higher than the concentration of that substance in the cell fluid would cause the cells to...? A concentration of sodium chloride lower than the concentration of that substance in the cell fluid would cause the cells to...? To complete your entry send us: a. Written answers to all the questions and your Table. b. Please complete the entry form (Chemistry Contest Entry Form found on this web site) and attach it to your entry. Entries should be postmarked by Friday, November 7, c. Send your entry with a self-addressed stamped envelope (refer to Chemistry Contest General Information also found on this web site for details) to: Dr. Mark Waner Department of Chemistry John Carroll University North Park Boulevard University Heights, Ohio National Chemistry Week Contest Page 5