Today I’m sharing a two-part experiment that we did to understand the relationship between ice and salt. This ice melt experiment is a wonderfully engaging way to explore some scientific concepts.
We’ve been doing a lot of ice-related experiments lately. Ice experiments are a great way to teach about states of matter (solid-liquid-gas) and physical changes. Plus, I don’t know why, but my kids get SO EXCITED about ice. It’s the coolest thing ever, y’all. See what I did there? Fun with puns!
So this is a two-part experiment that explores the properties of different liquids and their relationship with freezing temperatures.
Part 1: Which liquids freeze?
We had done some super-basic experiments with freezing water and thawing ice. I asked my son to think about other liquids (I discovered that he was under the impression that “water” and “liquid” were the same thing so we ironed that out first) and to think about whether or not those liquids might also freeze.
I set this up as a more classic experiment using the Scientific Method. Sometimes we are more free flowing and other times we write things down properly, I try to have a balance of both. We found 9 different liquids in the house, made predictions about what would happen in the freezer overnight, and then observed what happened the next morning. Yeah, he was SO EXCITED to see what the outcome would be he tried to make me get out of bed at like 6:00 AM to come see. Homeschool life.
These were the liquids we tested: Water (control), Saltwater, Sugarwater, Water with food coloring, Milk, Juice, Oil, Honey, Mouthwash, and Liquid Soap
He enjoyed gathering the liquids and filling each dish, carefully labeling each one. By the next morning they were all frozen solid with the exception of the Saltwater and the Honey was a little sticky, which leads into a discussion of viscosity… but the main idea is that the salt keeps the water from freezing completely.
Part 2: Why do we put salt on walkways in winter?
I love that there’s a real-life context for this experiment. We recently had The Great Blizzard of 2016 here in Maryland and our streets and sidewalks are coated with a salty film to break down ice and snow. I wanted my son to draw on the results of the first experiment to form a hypothesis about why they would spread salt on our sidewalk.
I put three figures into a plastic packaging insert (the tray from a box of cookies) and filled it up with water. The two Safari Ltd. figures sunk but the Lego dude floated, so that made for a neat effect. I froze it in the refrigerator and when it was solid, I asked him to think of ways to melt the ice and free the divers and sea turtle. This time the experiment was more about discussion and hands-on trial and error. We knew that doing nothing would eventually melt the ice, but was there a way to melt it faster?
I gave him a tray of water, salt and sugar. The try is a dollar store deviled egg tray, which is actually pretty perfect for experimenting and mixing things up.
While we noticed a slight change when the sugarwater was applied (due to just the room temperature water) but the salt had a much more significant effect. He really enjoyed excavating the little figures and had fun messing around with the melted ice and other materials.
We’re going to carry on with more experiments involving ice so be on the lookout for those posts and probably some day in the life updates on Instagram.
Are your kids crazy for ice? (Mine want to EAT it.) What are other cool ways to experiment with ice?