If you live someplace where the temperatures drop below freezing then you are familiar with Frost. We have left for school on many a morning and have seen the grass covered in a white shiny frost. With my oldest daughter being six and my youngest three, you can imagine that I have been asked on several occasions “MOM WHAT’S THAT!” So I thought we would do a simple Frost Experiment to show the girls what frost is and how it is formed.
This experiment is very easy and only takes a few minutes for the frost to form. But the kids really enjoy it because not only can they see the frost that they have been curious about, but they can touch it and even taste it (yep they both put their frosty finger in their mouths).
What is happening with this experiment? The salt lowers the melting point of the ice and causes the surface of the can to be at a below freezing temperature. Then the water vapor in the air around the can condenses and freezes on the can causing the Frost.
Frost will only form on the can if the temperature is below freezing, so if you just add the ice to the can with out the salt to lower the melting point you will get condensation on the can but not Frost.
Salt (rock salt or sea salt work better than table salt)