The Very Strange Properties of Cornstarch…
Posted by Science Oxford on December 29, 2009 | comments
This is a great video that really demonstrates the strange properties of Cornstarch and water.
Cornstarch and custard powder, when mixed with water have very strange properties. If you hit it hard or try to move it fast it hardens, but if you move it slowly it’s like a liquid.
Check out the video below:
If you wanted to try this at home all you need is:
- A cup cornstarch
- A bowl
- About half a cup of water
- A spoon
- A small tray
- (Optional) Food colouring
Directions:
Simply empty your cup of starch into the bowl. Stir while you add the water slowly, keep adding until the consistency becomes like thick pancake batter. If you wanted to add food colouring, add a couple of drops at this point.
Now is this time to have a play:
- Stick your hands into the mixture.
- What does it feel like?
- What happens when you slap the surface or try to roll some into a ball and then leave it alone?
So whats going on?
I’m sure you would have heard about states of matter, we usually talk about the three types: solids, liquids and gases.
A mixture of cornstarch and water make what is known as a suspension. When you squeeze a Cornstarch Suspension it really feels like a solid because its molecules line up. But it looks like a liquid and acts like a liquid when no one is pressing on it because the molecules relax. This is another state of matter, called a suspension (It can act like a liquid, or, when pressed like a solid.).
15
Jan
This used to be a party favorite when I was a teenager. We’d put a bunch of cornstarch in a bathtub and mix it up. We called it “gooshballs.” Provided lots of entertainment for us. ‘Course, this was before video games took off….