Ice Fishing Winter Science Experiment

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How can you pick up an ice cube with a piece of string? It seems impossible at first, but that’s why this ice fishing science experiment is super fun with your kid!

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How do you pick up a piece of ice in water with a string? Nope, you are not allowed to touch the ice in any way. You are also not allowed to tie a knot in the string.

I will give you a minute to think.

Still nothing? No worries, this ice fishing experiment stumped many adults as well. So you can imagine how magical this science experiment is for kids!

Ok, without further ado, here is how the magic happens.

How to Pick Up Ice with a String

Supplies:

Ice-Cube-Fishing

Directions:

  1. Make ice cubes! You can add food coloring if you wish to make the ice cubes colorful. We used red food coloring and used heart molds because it’s less than 2 weeks until Valentine’s Day!
  2. Fill a bowl ¾ full with water.
  3. Put the ice cubes in the water. Wait until the ice cubes float to the top. 
    Ice-Cube-Fishing-1
  4. Give your child a piece of string and ask him or her to try and pick up an ice cube with the string.
    Ice-Cube-Fishing-2
  5. After a few tries, demonstrate that you can’t do it either. I like to do this to make my child feel better about not being able to pick up the ice cubes. The whole “it’s not just you, nobody can do it.”
  6. Place one end of the string on top of an ice cube.
  7. Sprinkle salt on the ice cube where the string is touching. Tip: I like to pour some salt in a little bowl and let my kids use their fingers to sprinkle the salt. It’s better than risking having the entire container worth of salt ending up in the bowl.
    Ice-Cube-Fishing-3
  8. Wait about 20 seconds. You can count out loud with your kids to build excitement.
  9. Carefully pull the string upward and lift the ice cube out of the water. 
    Ice-Cube-Fishing-4
  10. Magic! Now you can fish ice cubes with a string!

The Science Behind the Ice Cube Fishing Experiment

Salt lowers the water’s freezing point. This means that water with the effect of salt must be cooled to a lower temperature for freezing to occur. As a result, the ice started to melt.

As the ice melted, the string was able to sink into the little crevice that it created. Since the surrounding temperature was still freezing, the ice started to freeze again. As the cube started to refreeze, a layer of ice formed over the string, trapping the string with the ice cube.

And that’s why you need to wait about 20 seconds for the ice to melt and refreeze before lifting up the string!

Final Thoughts on Ice Fishing with a String

How much salt you put on the ice is not an exact science, especially when your kid is the one doing it. Therefore, adjust the time you wait accordingly. If there is a lot of salt on the ice cube, then it might take longer for the ice cube to refreeze.

Hope you and your kids enjoyed bouncing the egg! For more awesome science experiments, check out:

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