Go “fishing” for ice in this cool experiment!
Age Group: Elementary School
Topics: Freezing point, dilution
Difficulty: Easy to perform and see results
Materials:
Ice
String
Stick (optional)
Tape/Glue (optional)
Salt
Bowl
Water
Procedure:
1. Fill the bowl halfway full with water
2. Place a couple ice cubes in the water. They will bounce for a bit, then float on top of the bowl
3. Take your string and attach it to stick with your glue or tape. This step is optional, however, it will allow you to have better control of your string
4. Lay the string across the ice cubes in the bowl
5. Sprinkle salt on top of the string and ice and hold the string in place for 10-15 seconds
6. Lift up the string and see all the ice you “fished” for!
How It Works:
When we sprinkle salt on the ice, the freezing point of the ice goes down. This happens because the salt interferes with the structure of how water is bonded in ice, causing for the bonds between water molecules to weaken. This weakened bond between the molecules causes for the freezing point to go down. With the freezing point dropped, the ice begins to melt, causing for the string to sing into the ice. However, as the ice melts, the salt gets diluted by the liquid water that has melted from the ice. This causes the freezing point of ice to go back up, causing the melted ice (water) to freeze back into ice, freezing around the string. This allows you to “fish” for the ice and have the ice attach to the string.