Does salt water freeze? Ask some penguins and polar bears! They know!

We need four more jars with lids. Each of the jars will be half-full of water, and we will dissolve different amounts of salt in each one. Let's also freeze a jar with plain water, just to see the difference. We will label the jars as to how much salt is in each one. Check the time, and write it down. Put on the jar lids, and put them into the freezer.

We will check them every half-hour, for four hours, to see how long they take to freeze, and we want to write down the times when they are frozen.

Did all the salt water freeze?

If some of them didn't, why do you suppose that is?

Now, we will leave the jars on the countertop, and keep track to see which one thaws first.

We can do this same experiment with different liquids. Think of some, and we'll decide which ones would be the most fun.