Sodium acetate instant crystals

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Sodium acetate instant crystals
Age Range 5-8 (grades 1-2), 8-11 (grades 3-5), 11-14 (grades 6-8), 14-18 (grades 9-12)
Group Size medium (6-20)
Setting indoors
Setup Time medium (6-30 min)
Duration medium (11-30 min)
Subjects states of matter
Key terms matter, sodium acetate, supersaturated, crystal
Materials none
Alias hot ice
Presentation Style demonstration

Brief Description

The leader will show crystals form right before your eyes by dropping a single crystal of sodium acetate into a solution of supersaturated liquid sodium acetate.

Scientific Background

Sodium acetate is a non-toxic (but smelly) left over from the chemical reaction that occurs when you mix baking soda and vinegar.

When you dissolve sugar in water, you reach a point where the sugar cannot be dissolved anymore. This solution is said to be "saturated." However, if you heat this solution, more sugar will dissolve. When the solution is cooled, the sugar will remain in solution. This is called a supersaturated solution, which is very unstable and will crystallize easily. The process of crystallization gives off heat. It’s said to be exothermic. That’s why the solution is used in hand warmers (the old-style liquid-type of hand warmers). This is the reason why another name for this activity is called "hot ice."

This Is How You Play

Before you can demo this reaction, you must have some sodium acetate! You can either buy it or make it. If you want to make it, please visit the link at the bottom of the page.

  1. Put about a cup of water into begin putting sodium acetate into water and stirring it so it dissolves.
  2. Heat up the water to boiling and keep dissolving sodium acetate until you cannot dissolve anymore.
  3. Let the solution cool to room temperature. Once cooled, you only need to add one single small crystal to the solution and the whole solution begins to crystallize. Check out the video on this page for a demonstration.

See Also


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