Bring Your Kids’ Attention to Unusual BehaviorsA lot of our “science” doesn’t happen at any sort of desk, but evolves from conversations during our walks to the park or around the block. On one of our walks I asked Smarty if she can think of a substance that expands when cooled. That was relatively easy, since we did experiments with floating ice more than once. Then I asked her if she can name a substance that would contract when heated, and she was stumped. I told her that I would show her one when we come home and pulled out a Shrinky Dinks set from a Dollar store.
Why Do Shrinky Dinks Shrink?
The science behind Shrinky Dinks is relatively simple, and my 8 year old could grasp it easily. Shrinky Dinks are made out of polystyrene which is a polymer. Polystyrene is not in its natural state when it’s heated, rolled out under pressure into thin sheets and then presented to us as a plastic container or a Shrinky Dinks kit. Molecular chains within polystyrene want to “clump” together and heating up a thin sheet of plastic allows them to return to their more natural state. By the way, my daughter insisted that cooked Shrinky Dinks are heavier, so we had a chance to talk a bit about mass conservation as well, but we didn’t weigh them before and after to prove the point. I suppose though they could technically be heavier if there is air trapped inside thicker Shrinky Dinks shapes.
Why Does Water Expand When It Freezes?
This is actually a more difficult for younger children to comprehend, but we watched this short video that explained the reason behind this behavior (hydrogen bonds) quite well. And to reinforce the lesson, we made “an ice pencil” by freezing water in a small plastic bottle. We did it several times before, but it still looks like magic when ice starts to peek out of the bottle.
More Science for Kids?
- Watch molecules attract
- Think like a scientist – separate two materials
- How temperature affects molecular movement
Follow Natalie Planet Smarty Pants's board States of Matter on Pinterest.