Activity
Almost all the field corn grown in Kansas is used to feed livestock or to make fuel. A small percentage of Kansas’ corn is used in many household products and as ingredient in many food items. However, one product made from corn is very fun to play with, cornstarch! Cornstarch is a powder that comes from the starchy long sugars, known as carbohydrates, found in a corn kernel. When cornstarch and water are mixed in the right proportions, they create a substance called Oobleck, named after the book by Dr. Seuss titled, Bartholomew and the Oobleck. This crazy substance is a liquid when you play with it really slowly but will turn to a solid if you go too fast! Not only is it fun to play with, but we can use cornstarch to thicken our gravy to pour over our mashed potatoes. We also use it in all kinds of food we eat like sauces, soups and even desserts!
Let’s make some Oobleck and play with it!
Instructions
- Fill a cup with 4 level tablespoons of cornstarch.
- Add 2 tablespoons of water.
- Mix together with a popsicle stick.
- You want a batter-like consistency that easily flows when slowly stirred but heavily thickens when quickly stirred or when a force is applied to it.
- Adjust with a tiny bit more cornstarch if too runny or a tiny bit more water if it’s too thick and powdery.
- Play with it!
What to do with Oobleck
- Stir it fast, stir it slow.
- Pour it into your hands. Form it, roll it, mess with it; then stop and try to hold it in your hands.
- Toss it in the air and then catch it. Toss it back and forth with a parent or friend.
- Toss it in the air and let it hit the ground.
- Toss it like a baseball and hit it with a plastic bat. Please use eyewear protection.
- Place it on the ground and hit it with a hammer. Please use eyewear protection.
Explanation
Water surrounds the starch molecules which allow them to slowly move freely, making it a liquid. But when moved too fast the water gets pushed out and the starch molecules collide with each other, forming a solid. Then when stopped, the water molecules move back in between the starch molecules to return to a liquid.
Let’s make more Oobleck!
Make a large amount of it! Use a bowl or a cake pan or a kiddie swimming pool!
- Slowly place your whole hand in it. Squeeze it gently and then quickly. Then try to pull your hand out as fast as you can!
- Claw across the surface of Oobleck with your fingernails.
- Place your feet in it. Step in and out of it at different speeds. Can you keep from sinking?
- Punch the surface of the Oobleck slowly at first and then harder and harder.
- Parent Supervision:
- Place a block of wood on top of the Oobleck. Then, carefully, try to hammer a nail into the wood block.
- Place plastic wrap over the diaphragm (or cone) of an old speaker. Pour some Oobleck in the center. Play some music with different amounts of bass. Watch the Oobleck dance!