Join our 4-H teen as he steps into the world of chemical science.
What are we learning today?
Have you ever tried to pick up an ice cube using only a piece of string? It sounds impossible, but with a little bit of science and some salt, you can do it!
We can make this happen using freezing point depression. This is when a liquid, like water, freezes at a lower temperature than normal because something, like salt, has been mixed into it. This is why we put salt on the roads during the winter, so the water doesn't freeze as quickly.
What do you need?
- 4 clear glasses
- Cold water
- Ice cubes
- Salt
- 4 pieces of string (about 12 inches long)
- Sticky notes
- Timer or watch
Try it yourself!
- Fill each glass with cold water, then add a few ice cubes. Make sure the ice is floating right at the water's surface.
- Take a piece of string and lay it across the top of one of the ice cubes in the first glass.
- Try lifting the string. Does the ice stick?
- Try again with the second glass. Place the string across the top again, this time sprinkling salt right on top of it.
- Make sure to label this one with a sticky note.
- Wait a few seconds, then lift the string again.
- Now on to the final two glasses. Again, place a string across the top of an ice cube in each one.
- Add salt to just one of the glasses and mark it.
- Set a timer for two minutes.
- Once the time is up, gently lift the strings and observe the results.
Open and print the supply list for yourself!
Want to learn more?