Slime Time

Activity Time: 30 minutes
Recommended Grade: 2 and up
Objectives: Investigate whether slime is a solid or a liquid in this experiment to explore observable properties.

  • One cup of cornstarch
  • ½ cup of water
  • Ziploc bag
  • Penny
  • Popsicle stick
  • Plate
  1. Take out all the ingredients for making your slime. These are your cornstarch, water, and a plastic Ziploc baggie. What adjectives would you use to describe these materials? Are some soft and pushy? Are others wet? Are any of them stretchy or see-through?
  2. These adjectives are your ingredients’ observable properties. In chemistry, scientists use these to classify the things around us as either solids, liquids, or gases. How would you classify your ingredients thus far? Are they all solids? Are there any liquids and gases?
  3. Next, add the water into your cornstarch into your Ziploc baggie of water.
  4. Mix the cornstarch and water together by kneading the mixture from the outside of the baggie with your hands.
  5. After the cornstarch is thoroughly mixed into your water, pour the contents onto the plate.
  6. What kinds of adjectives can we use to describe it now?
  7. To help come up with some adjectives, try rolling it into a ball, cutting it in half with your popsicle stick or a plastic knife, or dropping a penny into it.
  8. Now that you’ve experimented with it, would you say the slime is a solid or a liquid?

Both silly putty and slime are considered non-Newtonian fluids, which means they have properties of both solids and liquids. That was probably why you may have had some trouble deciding on which one best described it. As you may have seen in your experiments, slime acts more like a solid when a fast force acts upon it. This can be seen when we smack it, punch it, or press on it quickly and then let go. However, it acts more like a liquid when a slow pressure is placed on it. So your penny may have sunk into the slime and your finger may be able to make a big dent in the slime when you press and hold for just a few seconds versus if you press really hard and then let go. Do you think we could walk across a pool of slime? That would be a lot of fun!

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