Saturday, April 16, 2011

Can you Change the Freezing Point of Water?

Water freezes (from a liquid to a solid) at 32 degrees F. or 0 degrees C.

Challenge the students to think of a substance that could be added to the water (before or after it freezes) to LOWER the freezing point of water.

Hint: What do we add to our streets and sidewalks to prevent them from freezing or refreezing in the cold winter months if we live in cold snowy climates? (salt, rock salt, etc.)

Activity: Can you pick up a piece of ice with a string?

  • plate 
  • ice cube
  • piece of string
  • salt

  • Place the ice cube on a plate or table.
  • Have students try to pick up the ice cube with the string.
  • Place the string over the ice cube and pour a small amount of SALT over the string.
  • Wait 15 seconds.
  • Observe what happens to the ice cube.
  • Try to pick up the ice cube.

  • The salt lowers the freezing point of the ice and it starts to melt. Then as the ice melts and dilutes the salt solution the water refreezes with the string in the ice.

  • This is why salt is scattered on icy roads and walkways to make the ice melt.


  1. Hi! New follower thru GFC from the blog hops! Never thought about at what point water freezes. Thanks for the info. I am new (about 4 months) and am considering doing reveiws but no contests yet til I master the reviews. I found out yesterday they look at fans on Facebook and followers are Twitter as well as follwers on your blog. That has thrown a wrench in my plans as I concentrated on blog followers. I would appreciate a follow however which way you choose and if you need me to follow another way besides GFC let me know and I will return the favor. Thanks. Have a great weekend!


  2. this is super cool ! I love your blog !
    Happy blog hop and come follow me !

  3. Thank you for swinging by 2 Against 1 , and linking up to the TGIF blog hop (Friday). Hope to see you again next week! Following back now.

  4. I love it. My boys will have fun doing this.

  5. My husband loves to freeze the thread in the middle of an ice cube.



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