Ice Observations (Pre K and Kindergarten)
To start the new year of science lessons for our under 6 groups, I wanted to simplify our experiments and focus in on the nature of science. So I turned to the excellent New Zealand curriculum guide for inspiration. Their resources show excellent insight into the way children understand and work through science explorations. In particular, I thought it would be appropriate to study melting ice, given that it's winter, and, well, parents could learn a lot about rock salts as well.
After an initial observation of ice cubes fresh from the freezer as a group (What colour is it? What shape is it? What does it feel like? Hot or cold?), I gave the kids access to funnels, epsom salt, table salt, warm water and paint brushes. Then they could go wild with their tests. With the kindergarteners, I asked the kids to draw what they saw at various stages. We are using simple visual observation sheets this time around, based on the NZ curriculum.
This experiment worked particularly well with the kindergarteners, who held high levels of focus throughout the experiment, often calling me over to show how salt had melted a spot or red paint had turned the ice cube red. You can see their observation sheets at the end of this video.
Try this out with your 5-6 year olds. It's really great to talk about what they discover with them.
Questions for adults to think about:
[faq-toggle title="What melts faster, table salt or chunkier sea salt? Why do we use chunky salt on sidewalks?" color="white"]I'm no expert on this, but our experiments showed that table salt melted things a bit faster (likely because it has more surface area in contact with the ice), but the sea salt broke the ice up more as it went. Basically, the table salt resulted in a smooth and still slippery ice, while coarse salt cracked and broke down quickly.
It's also worth noting that the salt we use on roads has other chemicals in it. [/faq-toggle]
[faq-toggle title="How about how the mixture gets colder as it melts?" ]The WHOLE system's temperature drops to that of frozen saltwater when the salt is added. But now, it's even further away from room temperature than the regular water, and it takes in more energy to warm it up and melt the whole thing. [/faq-toggle]