Good afternoon scientists! We have a neat activity for you today. This one just requires yarn, ice, and salt. We are going fishing for ice! 🙂
Adults Only Optional Scissors (to cut the yarn)
NEVER LET YOUR CHILD PUT SALT AND ICE ON THEMSELVES!
IT IS DANGEROUS AND COULD CAUSE BURNING!
- Give your little scientist a piece of yarn and an ice cube, have them attempt to “fish” for the ice cube by letting the ice melt slightly then trying to pick up the ice using only the yarn.
- After trying to pick-up the ice cube unsuccessfully, place the yarn on a slightly melted ice cube and sprinkle some salt unto the ice cube. Let sit for about a minute.
- Admire your “fishing” skills as you lift the string.
You and your little scientist may be wondering why did adding salt allow you to successfully catch your ice cube, the answer is the salt changed the freezing point and melting point of the ice cube. Freezing point is the temperature that liquid changes to a solid when cooled. Melting point is the temperature that a solid changes into a liquid (melts). Water has a freezing/melting point of 32 degrees Fahrenheit or 0 degrees Celsius. Salt water has a freezing/melting point of 28.8 degrees Fahrenheit. Heat (hot, warmth) always moves from hot to cold until the temperatures are equal. By adding salt to your ice cube you are actually causing it to melt along where the salt is laying. The yarn is able to stick because the ice cube is cold enough to freeze again slightly causing the yarn to stick.