This experiment will explore whether adding different substances to a gel affects its strength.
-Can additives affect a gel’s chemical properties?
-What sort of chemicals make a gel the strongest?
We enjoy gel in our Jell-O pudding desserts as well as in our household glue, hair products and more. How many types of glue can you find in your house? Knowing why some gels are stronger than others, and how to strengthen weak gels, can come in handy the next time you need to glue something together.
- Ice cube tray
- Aluminum foil
- 2 packages of unflavored gelatin
- Paper cup
- Kitchen scale
- 2 pans
- Citric acid
- Table salt
- Cover your work area with some newspaper for easy cleanup, and then add two tablespoons of sugar to three ice cube compartments.
- Pour two tablespoons of citric acid to three other compartments.
- Next, add two tablespoons of salt each to three other compartments.
- Keep three compartments empty, this will be your control.
- Label each compartment accordingly.
- Next, make the gelatin by pouring two cups of water into a pan, and add the gelatin mix and stir.
- In another pan, bring two cups of water to a boil.
- Pour the boiling water into the first pan and stir the mixture until the gelatin is completely dissolved.
- Fill each ice cube container in your tray up to the top with the gelatin.
- Cover the tray tightly with foil, and refrigerate overnight.
- While waiting for the gels to set, poke a toothpick through the center of the bottom of a paper cup. This will be the tool used to measure the strength of your gels.
- When the gels are set, remove the tray from the refrigerator and poke the toothpick through the foil over one of the molds, so that it rests on top of the gelatin.
- Add a penny to the cup slowly. Every time the toothpick sinks into the gel and the cup descends, stop adding pennies until it stops again. Continue adding until the bottom of the cup touches the surface of the foil.
- Take the pennies out and weigh them in a kitchen scale, and record the weight in your journal.
- Repeat steps 10 to 12 for all the gels in your tray.
- Now it’s time to analyze your data. How does the gelatin react with the chemicals? How does each chemical affect the gelatin’s strength? Are there practical applications for this information?
Concepts: gel, additives, collagen