You can make ice cream with guar gum…
Or you can make goop!
The image above depicts guar beans, the legume used to make guar gum.
- 2 teaspoons guar gum (found in health food stores). (Amazon link: Guar Gum)
- 1 tablespoon Borax (found in grocery stores). (Amazon link: Borax)
- warm water
- mixing bowl
- food coloring (optional). (Amazon link: Food Color)
- 2 empty plastic soda bottles to store the liquids
- Ziploc bag (Amazon link: Ziploc Gallon Bags)
*Get an Adult* While guar gum and borax are not considered hazardous, you should treat these and all other chemicals with care and WASH YOUR HANDS after you handle them. DO NOT taste or eat any of the materials described in this experiment. DO NOT pour goo down the sink! IMMEDIATELY clean up any spills that occur throughout the experiment.
1. Add 1 tablespoon Borax powder to 1 cup warm water. Stir until most of the powder dissolves. Store the Borax solution in a soda bottle. Label this container “BORAX & WATER MIXTURE”. Remember that this quantity can make many batches of goop.
2. Measure 4 cups (approximately 1 liter) of warm water into a large mixing bowl. If you want, add 10 drops of food coloring. VERY SLOWLY stir in 2 teaspoons guar gum. The powder may clump up if you don’t add it slowly, so be careful. After you mix the guar gum solution thoroughly, pour it into a soda bottle and label it GUAR GUM MIXTURE.
3. Pour 1/2 cup of your guar gum mixture into a clean Ziploc bag. Then, add 1 teaspoon of the Borax solution you prepared in Step 1. Seal the bag and shake. After a couple seconds, the mixture will clump up into a batch of goo! This gooey mixture will stay slimy for about 1-2 days. After this, it will turn into a watery substance. Once it does, seal it in the Ziploc bag and throw it away. DO NOT pour it down the drain. Note: you can prolong the shelf life of your goo by storing it in the fridge.
Guar gum comes from the seeds of the guar plant, Cyamopsis tetragonoloba, which is native to India. Guar gum is a polysaccharide, which is made up of molecules linked together in long chains to form a polymer. After the guar gum is mixed with water, these long chains capture some of the water molecules and get tangled up with each other. The result is a very viscous liquid. This is why guar gum acts as a good thickening agent in various food products and cosmetics.
Once you mix the guar gum mixture with the borax mixture, cross-linking occurs between the borate ions in the borax and the guar gum polymer chains. (See my Gak page under the “Slime” menu for more information on cross-linking). As a model for these polymer chains, picture a plate of cooked spaghetti. If the chains slide past each other easily, then the substance acts like a liquid since there is more molecular flow. If the molecules “stick” together at a few places along the strand, then the substance behaves like a rubbery solid called an elastomer. The result is “goop.”
Want more slimy recipes? Check out these links: