Ice Games (2)

Objective: To explore the process of melting, and to go "ice fishing"

Outcomes: Identify the properties of solids, liquids and gasses; investigate changes to the properties of matter when it is heated or cooled; describe physical properties of air, water, and soil

Materials: Ice cubes; plates; dark cloth or dark paper; string; salt; paper towels; cup of water; tin foil

Doing it:
Ice race: "How long do you think it takes an ice cube to melt?" Each person receives paper towels and a certain number of ice cubes on a plate. "Who can completely melt their ice cubes first?" People can heat their ice by any means except smashing the cubes, putting them in their mouths, or applying heat from something like a match. Dark paper or dark cloth should be made available, as well as salt and tinfoil. When the race is over, describe the steps in the melting process.
Ice fishing: Put an ice cube in a cup of water. Lay a piece of string over the ice cube. Sprinkle a little bit of salt over the string, and wait a few minutes. Lift the string. "What happens? Why?"

Explanation: There are a thousand ways to melt an ice cube. You could hold it in your hands, which are warm. You could make your hands warmer by rubbing them together. You could place it in the sun, or better yet, place it on a dark cloth in the sun. The dark fabric will absorb heat more easily. Placing the ice cube on tin foil will slow the melting down, because the tin foil will reflect most heat, but it could be used to reflect light onto the dark material. Salt is another way to get ice to melt. Salt lowers the freezing point of water. This means the ice below the string will melt and then refreeze, holding the string to it. This is why workers salt the roads on icy days. Whether something is solid, liquid, or gas depends on the type of matter as well as the temperature. Metal won't melt until it is quite hot, while ice melts at 0 degrees Celsius.

Tips:
-For "Ice Fishing" to work, the cube being used must be relatively small (about the size of one or two 9 volt batteries) otherwise the string will be ripped off the ice before it can be lifted.
-When placing the string over the ice cube, make sure it is in contact with the ice in a location where there is also salt
-Do "Ice Race" outside or it will take quite a while to complete