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Science Fair Projects: Make Ice Melt with Salt

Ice forms when it changes from its liquid state- water, to its solid state- ice. This transformation of states occurs when water is frozen below 0ºC, 32ºF, or 273.15K. Due to the water's various factors and environment, the transparency and coloring of the ice will vary. Ice can be a clear-white color or an off white-blue. Many of these subtle changes can be caused from air, soil, or impurities. Did you ever notice that really cloudy color in your ice cubes? That is due to all the air bubbles when the water was freezing. Those air bubbles get trapped, causing the cloudy look.

Melting Ice Cubes with Salt

Ice that naturally forms in nature can take on many different shapes, sizes, and colors. From the huge glaciers in the ocean to the small hail that falls from the sky, ice is everywhere.

Many say that the cause for salt melting ice is because salt lowers water's freezing point. Therefore, by lowering the water's freezing point, it disrupts its molecular equilibrium. Due to a salt's different variation, the molecular compositions and elemental concentrations vary.

    Problem:
  • Which salt melts ice the quickest?
      • Materials:
      • Regular table salt
      • Kosher salt
      • Epsom salt
      • Rock salt
      • 5 blocks of ice
      • Clear plastic containers

      Salt Melts Ice Cubes

      Procedure:

      1. First, you need to prepare your blocks of ice. If you still need to get your blocks of ice, an easy replacement is to just place some water in the freezer for a bit.
      2. Next, you should place the ice in the separate containers. Be sure to label each container with the type of salt you are going to use.
      3. Next, be sure to use the same amount of salt for all ice blocks. Variation in amount of salt can influence your outcome. Use 2 tablespoons of each salt on their corresponding block of ice. Now you must watch and observe. 10-minute intervals are good times to check on the ice.
      4. Observe the progress of the melting ice and record your findings until all the ice has melted.
      5. Record your results. How fast did it take for all the ice to melt in each container?

      Smart Tip: Take a picture of each ice container at every stage of the process - prior to salt addition, first 10-minute interval, second 10-minute interval, etc. This will give you some good material to go back to for reference, and make your project more engaging!