Home School Programs – Liquid Solid

Sometimes science can seem like real magic. With this experiment, you’ll get a hands-on look at how easy it is to use simple chemistry to turn a liquid into a solid. This is a great experiment for all types of home school programs – and makes home school programs simply unforgettable!

If you’re ready to get started, then take a moment to gather the following materials together:
    •    About ¼ cup of corn starch
    •    About ¼ cup of water
    •    One mixing bowl
    •    Newspaper

After you have all of these materials gathered together, you’re ready to get started. Here’s what you’ll need to do next:
    •    Place one sheet of the newspaper flat on a tabletop.
    •    Place your mixing bowl in the center of the newspaper.
    •    Add the cornstarch to the mixing bowl.
    •    Add two Tablespoons of water to the cornstarch and stir.
    •    Add more water slowly to the mixture until all of the cornstarch powder is wet and is a liquid. You’ll know the mixture is ready for the experiment because when you tap on the cornstarch mixture, it won’t splash, but will, instead, become hard. In other words, the mixture will be a stiff liquid.
    •    Put the cornstarch mixture in the center of your palm. Work the mixture into a ball. You can keep it a solid by putting pressure on it as you rub it between your hands. When you stop rubbing the cornstarch into a ball, it will seem to melt into a puddle.

Think this is a cool experiment so far? If you teach science at home, a great resource is the free Homeschool Science Experiment Guide and workbook.

Understanding what you observed:
Some liquids are resistant to flowing. When a liquid is resistant to flowing, it has a high viscosity. However, when the viscosity of a liquid is low, the liquid will flow like water. This is a great experiment for home school programs of all types, right? For example, compare water to honey. Honey has a low viscosity and water has a high viscosity. However, when you heat honey, the viscosity decreases, making hot honey flow like water.

When a fluid changes its viscosity when heated (or when the temperature changes), the liquid is called Newtonian. This is because Isaac Newton first described how this behavior works. A non-Newtonian mixture, such as the cornstarch mixture you made, has a viscosity that is determined not by the temperature of the liquid, but rather by the force applied to that liquid (or by how fast an object moves through the liquid, such as your palms rubbing together).

Can you think of any other non-Newtonian liquids? How about silly putty? Ketchup? Or even quicksand? In fact, ketchup actually decreases in viscosity when you apply pressure, which is why it’s easier to pour ketchup from a glass bottle when you shake it. Quicksand, on the other hand, becomes hard when you apply pressure (like the cornstarch), which makes it difficult to escape from quicksand if you struggle.

Pretty cool experiment, isn’t it? This is definitely an experiment you can use to impress your friends!