This week we continued learning about states of matter and took a solid, watched it turn into a liquid (partially) and then turn back into a solid.
We tried to lift an ice cube using string. Students had little success. Then, we sprinkled salt on the string and waited about three minutes and tried again.
Salt lowers the freezing point of water to below 32 degrees Fahrenheit. When we added salt to the ice cube, the salt lowered the melting point of the ice. The salt is in a thin layer, so it melts a thin layer on top of the ice cube. The water from the melty ice cube re-freezes itself around the string, almost as if the string were a part of the ice cube all along. Click below to watch this experiment in action!