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How to Make Crystals From Epsom Salt

Easy, fun, and way-cool chemistry activity making "frosted windows" with Epsom salt crystals. It's only 4 steps and just need 3 ingredients. Add to a winter study or a chemistry study. Easy to do for homeschool science or in a classroom science setting. Definitely a chemistry activity for elementary, middle school, and high school


  • 1/3 Cup Epsom salt (fragrant-free)
  • 1/2 Cup Boiling water It should be 1/2 cup after it has boiled.
  • 1 teaspoon Liquid dishwashing soap mixed with a few drops of water
  • 1 piece of glass (Glass from a photo frame works well.)
  • 1 Mixing spoon
  • 1 Mixing bowl


  • Pour the 1/3 cup of Epsom salt into a small bowl.
  • Add the ½ cup of boiling water.
  • Stir.
    While the Epsom salts are dissolving, explain to your child that the hot water molecules are moving faster and there is room in between those water molecules.The magnesium sulfate (Epsom salt) is able to dissolve and those atoms fill inthe free space between the water molecules. When there is no more room, thenthe Epsom salt won’t dissolve anymore.
    It’s also important to note. The magnesium sulfate didn’t changei ts state, it just dissolved.
    If your students are older, have them repeat this back to you in their own words to show understanding.
  • Set this solution aside.
  • Place the piece of glass on a work surface.
  • Dip a few fingers into the soap and cover the glass in a very thin film of soap.This helps with adhesion of the crystals and clean up.
  • Measure out 1 to 2 teaspoons of the solution. If you have a large piece of glass(over8x11), use 1.5 to 2 teaspoons.
  • Very carefully tilt the glass around to spread the solution.It won’t cover the entire glass. You just want to move it around a little.
  • Let the solution dry for 30 to 60 minutes. (We placed oursin front of a sunny window and it was dry in 45 minutes.)
  • Enjoy the “frosty" windows.
    How to Create Crystals from Epsom Salt