chemical formula of hot ice

Creating Hot Ice: A Great STEM Experiment For Summer

There’s a Dad joke waiting in this project.  Make sure to grab it while you can!

“Son, it’s been so hot this summer that even the ICE is hot!”  

You can buy ice in the supermarket but hot ice you’ll have to make yourself. Making hot ice is an easy fun experiment three to eight-year-old kids can try with ingredients you have at home. It takes about 1-2 hours to conduct the experiment.   Your children will be amazed as the “ice” forms yet isn’t cold at all!

Hot ice is used in hand warmers, heating pads, for a buffer in laboratory settings, and for pickling and tanning of food.  It’s chemical name is sodium acetate.

Supplies Needed

  • A heat safe measuring jar or glass cup 
  • 4 Cups of white vinegar which is acetic acid
  • 4 Tablespoons of baking soda which is sodium bicarbonate
  • Water 
  • Hot plate 
  • A dish
  • A spoon or spatula
  • A pot or saucepan (do not use a copper pot)

What Mystery Are We Solving?

Make hot ice and when you put your hand in the liquid the hot ice is formed around your fingers. It looks like your fingers are frozen, but it is hot to the touch.  

How does to everyday ingredients create ice that is hot to the touch? Isn’t ice supposed to be cold?

Safety Issues

Although young kids can create their own hot ice, adult supervision is recommended when the liquid is boiled.  

Hot ice isn’t the same as dry ice! Dry ice may cause severe burns when touched but hot ice is mostly harmless. For some people, hot ice may irritate skin and eyes in the same manner vinegar would. 

How To Make Hot Ice

  1. Pour 4 cups of white vinegar into the saucepan or pot.
  2. Slowly add 4 tablespoons of baking soda a little at a time to the vinegar. The liquid fizzes when the baking soda is added. Stir with the spoon to mix the two ingredients as you add the baking soda.
  3. Wait for the fizzing to stop before you continue. 
  4. Place the pot on the hot plate and boil at medium heat until the fluid evaporates and you’re left with a dry solvent. It should take about 30-60 minutes for all the liquid to disappear. 
  5. When the liquid starts forming a crusty film on the surface, turn the heat down immediately to prevent it forming a thick crust. (Scrape some of the crystals off the side of the pot to use later)
  6. If the solution is brown and cloudy, add more vinegar. Boil again. 
  7. Break up the lumps in the powder solution.
  8. Place the powder in the glass container with a lid and add water until it dissolves into a liquid. (66 g of water for every 100 g of powder) Cover with the lid to prevent more evaporation. 
  9. Place the glass jar in a container with ice water to cool down. It takes about 15 minutes. You may also cool it in the fridge, but it will take longer than the ice water. 
  10. When you put your hand in the glass jar, the hot ice forms crystals around your hand and it is frozen to the touch.   

What Just Happened Here?

The chemical reaction is also exothermically creating the hot feeling when touching the ice.  

The physical change is noticeable when the liquid mixture releases gas and changes into a solid form. When water is added the powder dissolves.  

The solution is a supercooled liquid that stays liquid when cooled down below its freezing point in the ice water.  

The unstable supersaturated liquid will freeze forming crystals at the slightest trigger when adding some of the crystals to the solution. For a cool effect dip your fingers into the liquid. Crystallization forms at the nucleation site when solute molecules that bump into each other overcome the power of the solvent that keeps molecules apart 

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