Lesson 4 - What do fireworks, rubber, and Silly Putty have in common?

Activity: Great Goo Experiment

What is the ratio of borax and water?

You will want to mix 2 cups of water with 4 teaspoons of borax for a class of 32 students.

Goo did not form after mixing the borax and glue solutions. What should I do?

It is most likely related to the mineral levels in the tap water where you live. We recommend using water from a different source to see if that helps.

Is there a substitute for borax?

You can definitely make this without borax. Here is an alternative recipe: Alternative Recipes for Teacher Prep

What if students are allergic to milk?

Since milk is used as one of six test substances (and it doesn't really react with any of the other substances) it should be fine to skip the milk. They'll still be able to test the other five substances!

Activity: Great Goo Experiment - Silly Putty alternative recipe

Alternative Goo Recipes (without Borax)

In response to concerns about using borax to make goo, Mystery Science has developed alternative goo recipes, each with its own advantages and drawbacks. We have not thoroughly tested the measurements for these alternative recipes, so we encourage you to try this yourself before trying it with your students.

How to make goo using boric acid

For each student making goo, you will need:

• 2 Tablespoons glue
• ⅛ teaspoon baking soda
• 10 drops of eye drops that contain boric acid and sodium borate (we used CVS Redness Relief eye drops, but any brand that contains boric acid and sodium borate will work)
• A Dixie cup
• A stirring stick

Instructions:

• In the Dixie cup, mix the glue and the baking soda with the stirring stick.
• Add 10 drops of eyedrops.
• Stir, and goo will form. It takes this goo a little longer to form than the original goo with borax, so be patient. It may take as long as fifteen minutes.
• The more eyedrops you add, the thicker the goo will get.
• Initially, this goo will be very sticky. Over time, it will get firmer and less sticky.

We don’t recommend making this goo in a baggie. It tends to stick to the plastic, which makes it difficult to work within a baggie.

Advantages: This is a genuine chemical reaction (which is our goal in this lesson), and for some teachers, eye drops may be easier to obtain than borax powder.

Disadvantages: Boric acid contains a similar basic ingredient as borax, so has a similar risk level (which is still very low.)

How to make goo using cornstarch

This goo does not include borax in any of its forms.

For each student making goo, you will need:

• A Dixie cup of cornstarch
• ½ a Dixie cup of water
• A bowl or cup to mix the goo
• A stirring stick or spoon

Instructions:

• Put the water in your mixing bowl or cup.
• Add the cornstarch a little bit at a time, stirring it in after each addition.
• Keep stirring until you have goo. You can use your hands for mixing.
• You’ll notice that this goo sometimes acts like a solid, and sometimes, as a liquid.

Advantage: This does not involve borax in any of its forms.

Disadvantage: This is not, strictly speaking, a chemical reaction, but merely a mixing together of two substances.