Wikijunior:Big Book of Fun Science Experiments/Oobleck

Oobleck, Goo or Goop is a strange substance that has some of the properties of a liquid and a solid at the same time. Substances like this are called non-Newtonian fluids, because they do not follow the normal rules of solids and liquids. Newtonian solids, like wood or ice, hold their shape. Newtonian liquids, like oil or water, usually take the shape of the container they are in. Non-Newtonian fluids like Oobleck are sometimes liquids and sometimes solids.

If you have ever melted chocolate without stirring it, you will notice that the squares of chocolate hold their shape until you stir them up. Melted chocolate is also a non-Newtonian fluid.

The Experiment

Safety

As with all experiments, you should talk to an adult before trying to make Oobleck. Oobleck is safe to touch; however, it can be very messy. You should wear an apron to keep your clothes clean. If you get Oobleck on your clothes or on the floor, you can easily clean them up with water.

What You Need

Water
A cup of cornstarch
A bowl
A spoon

That's it, isn't that easy!

Instructions

Put about a cup of cornstarch into the bowl.
Pour about a cup and a half of water into the bowl and stir.

All the cornstarch should be covered in the water. There should be no dry cornstarch visible. If there is dry cornstarch, add a tiny bit more water and stir again. Keep adding a tiny bit of water and stirring until all the cornstarch is covered in water. The mixture should look wet but be difficult to stir, as if you are trying to stir a solid.

Dig in!

Note: If your oobleck starts getting too dry, just add a little more water and stir it again.

Things to Try

Pick up a handful of oobleck and squeeze it in your fist. Does it feel like a solid or liquid?

Now open your hand and hold it over the bowl. What happens? Now is the oobleck a solid or a liquid?

When is the oobleck a solid? When is it a liquid?

Find a small object such as a plastic toy and attempt to float the object on the oobleck. Can you do it?

What is Happening?

The cornstarch is suspended in the water as a starch and water mixture. A simplified explanation is: the starch molecules are long chains of atoms. When you let them move slowly, they can slide past each other. When you squeeze or hit them, they get tangled and cannot move.

However, scientists are still investigating strange substances like oobleck. There are still many questions to answer!