How to Make Goo

Make squishy nontoxic goo that hardens in your hands when you squeeze it but flows like a liquid when you pour it.

Difficulty: Easy

Time Required: Minutes

All you need for this project is cornstarch and water. You can add food coloring if desired. Feel free to experiment with the amount of water to see how it affects the properties of the goo.

• 16-oz. box cornstarch
• Water
• Food coloring
• Bowl

1. Empty the box of cornstarch into a bowl.
2. Add 1 1/2 cups of water.
3. Add about 15 drops of food coloring. It's fine without color, too.
4. Mix the goo with your hands.
5. Store goo in a sealed container when you're done using it. If it dries out, simply add more water.

Goo is a viscoelastic or non-Newtonian fluid, which means its viscosity (how readily it flows) depends on external conditions, such as pressure, shear, or tensile stress. If you pick up goo, it runs through your fingers. If you squeeze it or punch it, it seems to solidify. The force pushes the water around the cornstarch particles, allowing them to mesh together. Afterward, the water flows back to fill in the gaps.

Water isn't the only liquid you can use to make goo. Try using vegetable oil or a mixture of oil and water instead. This forms a goo with interesting electrical properties. Watch how this type of goo reacts when you place an electrically charged object near it (like a balloon you rubbed on your hair).