Science and Valentine’s Day

What better way to get children interested in Chemistry than to make Salt Crystal Hearts for Valentine’s Day. Children will enjoy learning about solutions, evaporation, and dissolving solids while they make salt crystal hearts for Valentine’s Day.


What make this a great experiment for teachers to try is that you don’t need to go buy any of the ingredients. All the ingredients are items you have at school or at home.

  • Table salt (Table salt will take a few days to grow. Iodized salts won’t work as well, but will still form crystals.)
  • Water
  • Pipe Cleaners
  • Pencils (1 per jar)
  • Mason Jars or Cups (Mason Jars work best so that the students can observe the heart throughout the day to see what is happening. If you do not have enough mason jars for your class, cups will work just as well. If you are using cups, I would recommend having a teacher heart in a mason jar that will allow students to make observations.)


1.  Heat up water in the microwave. You want to make sure the water is warm enough to dissolve the salt, but not too hot where it can burn students.

2.  Pour in 1/4 cup of salt into each container. Have the students stir in the salt until all the salt is dissolved.

3.  Pour the solution into another container making sure not of the undissolved crystals get into the new container. If there is undissolved salt grains in the jar, the crystals might grow around those grains instead of your heart.

4.  Have the students take a pipe cleaner and form it into a heart (check to make sure the heart can easily fit into the jars)

5.  Attach the hearts to the pencils using a small pipe cleaner or string.

6.  Place the hearts into the salt solution having the pencils sit on top the jars to keep the heart suspended in the solution.  If your heart touches the side or bottom of the container, your crystals will be small and lumpy.

7.  Observe the heart crystals for 24 to 48 hours. The longer the hearts are in the salt solution, the bigger the crystals on the hearts will get.

8.  Remove heart crystals and place them on a paper towel to dry.

9. Once dry, have the students use a magnifying glass to observe the crystals on the heart.

Science Concepts

Solution: A solution is a type of mixture where one substance is dissolved into another. In this experiment, the salt was dissolved into the water.

Dissolve: Dissolving is when the solute breaks up into smaller molecules. It the case of this experiment, the water is breaking the salt up into smaller molecules that cannot be seen. The salt is still in the water, it just can not be seen.

Evaporation: Evaporation is when the water (a liquid) turns into water vapor.

As the water evaporates from the salt water solution, it leaves the salt behind. The salt molecules will cling to anything nearby making the salt crystals form on that item.

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