Science Buddies: "Ask an Expert"

How does dissolving substances in water affect the freezing point of the solution?

I need more of a back round research for my project. Why did my project turn out this way?? I know salt melts ice, but in my experiment it was the opposite. The salt actually froze the ice in the ice bath. The sugar increased the temperature more than the salt . So I'm confused if my project should have happened the way it should. I added different amounts of salt and sugar to the ice bath and some of the temperatures increased (sugar) and some decreased ( salt) yet froze the ice bath. Please answer my question!!

Hello:

I'm not sure I understand what you were doing. I've read the experiment, and all of the solutions will freeze in the salt / ice bath. You are supposed to observe and record the temperature where the solutions freeze. They should all be above the -10 C temperature of the ice bath. Is that what you observed? If you could provide a procedure for what you did and what happened we may be able to help you more. Thanks.

Keith