Yuk ... This is Gross!

Making goop

Caution: Do not do this activity at your computer!

Many materials in our society are not made from natural substances. They are made by chemical reactions. Many fabrics are made of synthetic fibers. Wool is a natural fabric. It is made from the hair of sheep. Cotton is a natural fabric. It is made from plant fibers. Silk is a natural fiber. It is made from the cocoons of silkworms.

Other fibers are the products of chemical reactions. Some examples are nylon, rayon, and polyester. Anything you have that is made of plastic is the product of a chemical reaction. There are lots of other synthetic substances. Even some foods and medicines are artificial or have artificial ingredients.

Today, you are going to make a fun synthetic substance called "Goop." It is the product of a chemical reaction between a borax solution and white glue.

Materials:

• Borax powder (found with laundry detergent at the grocery store)
• White glue
• Balance or scale
• Paper cup
• Measuring containers
• Mixing container with lid (a cottage cheese container will work well)
• Water

Procedure:

1. To make a borax solution, measure 250 ml. of water and mix in 5 mg. of borax. Stir the solution until all the borax is dissolved. If a little will not dissolve, this is okay. Do not add more water.
2. Weigh the container in which you will be making your goop. Record the weight.
3. Measure 125 ml. of the borax solution and pour into the container. Weigh the solution in the container and record it.
4. Subtract the weight of the container from the total weight of the container with the borax solution. The difference is the weight of the borax solution. (You can save the other 125 milliliters of borax solution in case you want to do this again, or you may share it with a partner.)
5. Weigh the paper cup and record the weight.
6. Pour 125 ml. of white glue into the cup.
7. Weigh the cup with the glue.
8. Subtract the weight of the cup from the total weight of the cup with the glue to determine the weight of the glue.
9. Pour the glue into the borax solution. Try to get all of the glue out of the cup and into the mixing container. Use your finger to scrape the glue out. Then, use your hand to mix the glue and the borax solution.
10. Squeeze the glue between your fingers. Does it still feel like white glue? Does the feeling change as you continue to mix it?
11. As you mix the goop, some of it will stick to your hand. As it becomes stiffer and stiffer, you can scrape this off back into the container. Wiping your hand with borax solution helps remove the goop from your hand. Try not to lose any of the product or leftover solution, if any. Usually, not all of the solution combines chemically with the glue. Do not add more glue to try to use this up.
12. Describe the new product? Are its properties the same as the substances with which you started?
13. Keep kneading the goop. After a while, you can lift it out of the container and roll it between your hands. When you have it the way you want, return the product to the container along with any leftover borax solution. If any pieces of the product fell on the table or are sticking to your hands, try to gather them back into the container.
14. Weigh the container with the goop. Subtract the weight of the container from this weight. The difference is the weight of the substances in the container. If you spilled or lost anything, try to estimate how much was lost. Does the product and leftover solution weigh more, less, or about the same as the weight with which you started?
15. What do you think would happen if you did this again, but made the borax solution twice as strong? Ten times as strong? If you used something besides borax?

Finding the answers to questions like these is the way that scientists invent new products.

Analysis:

1. How does the total weight of your goop compare with the weight of the materials that you used to create it?
2. How do you think the materials combined to change the properties of your goop?