# Science Experiment: Polymers – Cornstarch Goo

Science Experiment: Polymers – Cornstarch Goo

Sir Isaac Newton is famous for figuring out certain rules that apply to things on earth. One of his rules is that matter can take three forms: solid, liquid and gas. Liquids flow and take the shape of the container they are in. You can see that happen when you pour a glass of water.

Usually matter turns into a liquid when it is heated and when liquid is heated it “gets runnier.” How easily a liquid flows is called viscosity. Water has a low viscosity and flows fast. Honey has a high viscosity and flows slowly. If you heat honey or lava…it flows faster. That is one of Sir Isaac’s rules too…that the viscosity of liquids goes up as the liquid is heated. Mix up this corn starch Goo and see how it behaves. Is it a liquid or is it a solid?

What You Need:

• Cornstarch
• Water
• Bowl
• Measuring Cup
• Cookie Sheet or Tray – with sides!
• Gallon Size Ziploc Bag (optional – for storage)

Put 1 cup of cornstarch in a mixing bowl. Add water slowly to the cornstarch – about 1/2 cup. Mix the cornstarch and water with your hands until it starts to feel like a sticky glue.  Try to pick up a handful of the goo. Squeeze your hand around the goo to make a fist around it. What happens? Now relax your hand. What happens now? Pour the goo onto a cookie sheet or tray. Make sure the sheet or tray has sides! Lay your hand on top of the goo and leave it there for a few seconds. Pull your hand straight up and watch what happens.

Cornstarch goo is an anomaly – that means it’s weird! It doesn’t act like it should. The cornstarch goo seems like a liquid because it flows off your fingers and it takes the shape of the container you put it in. But when you squeeze the goo…it turns into a solid. So which is it? A liquid or a solid? Cornstarch goo is called a non-Newtonian fluid because it doesn’t behave by Sir Isaac Newton’s rules.

Cornstarch goo is also a polymer. That means it’s molecules are arranged in a long chain. When the chain of molecules stretches…like the goo flowing off the fingers in this photo, the goo behaves like a liquid and flows. As soon as the goo has pressure applied to it – like when you squeeze it in your fist or when you rest your hand on it in the tray, it behaves like a solid and feels stiff and strong. With cornstarch goo, the viscosity changes when you put pressure on it instead of when you heat it. Weird again!

Science Project Idea: Get three bowls and measure 1 cup of a powdered substance into each bowl. 1 cup of cornstarch in bowl #1, 1 cup of baking soda in bowl #2 and 1 cup of flour in bowl #3. If you step back and look at the bowls they will all look pretty much the same – a bowl with white powder in it. Now pour 1/2 cup of water into each bowl and mix each bowl with your fingers. Do the mixtures behave the same? How do they behave differently? How would you describe each mixture? A solid or a liquid? You could also try baking soda and powdered sugar.

## Websites, Activities, Printables & Databases:

Science in Context: Polymer and Non-Newtonian Fluid is a database you can use in any IndyPL Library Branch or at home. Login using your IndyPL library card number. The Science in Context database will show you articles, images and videos to help you learn about polymers and non-Newtonian fluids.​

You can also ask a math and science expert for homework help by calling the Ask Rose Homework Hotline. They provide FREE math and science homework help to Indiana students in grades 6-12.

## Books:

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### 10 Responses »

1. The sentence “How easily a liquid flows is called viscosity.” has been updated to “Viscosity is how resistant a liquid is to flow. Flow is a liquid’s movement in a current or stream.” Do you think that clears it up? In the original sentence I think “how easily” was referring to a range from “easily” to “not easily”…rather than the single definition of “easily”. It was confusing. If you think the text is still confusing I would love a suggestion. Thank you!

2. Hi! I am a homeschooling mom and found your page. I am having difficulty understanding if you are giving correct information here. You list the definition of viscosity as how resistant to flowing a liquid is. That makes sense when you say water has low viscosity and flows quickly, honey has high viscosity (resistance) and flows slowly. In this paragraph however, you also say that viscosity is ‘how easily a liquid flows’. It seems that would be the opposite. A liquid that flows quickly like water would then have ‘high’ viscosity. So which is it, really? You say that low viscosity makes things able to flow more easily, but then you say heated liquids have ‘higher’ viscosity and flow quicker (usually). You seem to be contradicting yourself.
“Usually matter turns into a liquid when it is heated and when liquid is heated it “gets runnier.” How easily a liquid flows is called viscosity. Water has a low viscosity and flows fast. Honey has a high viscosity and flows slowly. If you heat honey or lava…it flows faster. That is one of Sir Isaac’s rules too…that the viscosity of liquids goes up as the liquid is heated.”

3. Cool i got to choose a procedure writing project and I choose quicksand goo and I’m only 11 and 5th grade and this helps a little so cool.

4. @Katniss this article in Science News for Kids http://www.sciencenewsforkids.org/2012/07/scientists-explain-why-a-liquid-like-cornstarch-and-water-can-sometimes-act-like-a-solid/ talks about what is happening with the water molecules in cornstarch goo to make it act like it does. This article Goo and the Physics of Everyday Stuff http://www.sciencenewsforkids.org/2012/07/scientists-explain-why-a-liquid-like-cornstarch-and-water-can-sometimes-act-like-a-solid/ talks about the behavior of the molecules too. Does that help?

5. I need the molecular physics behind this and I am only a 12 year old, 7th grade girl! CAN’T FIND THEM ANYWHERE