Monday, August 25, 2008


This activity takes a few days, up to a week, after the setup to grow the crystals. The result is a variety of beautiful crystals for students to observe and compare.


Gather as many of the following substances as you can: Epsom salt, Alum (found in the spice section at the grocery store), Borax (found in the laundry section in your grocery store), Rock salt
Hot water
A glass jar for each type of crystal grown
Cotton thread
A pencil for each type of crystal grown (or Popsicle stick)

Use appropriate safety precautions when using hot water. Have an adult present for use with hot water.


1.With an adult, heat water on stovetop. Pour into glass jar.
2.Add your substance (Alum, Borax, Epsom salt, or Rock salt) to the hot water until you cannot stir in any more substance. This is a saturated solution.
3.Pour the above solution off into a clean jar. Leave behind any undissolved salt.
4.Tie a thread to a pencil (or Popsicle stick) and suspend the thread into your solution. Bridge the opening of the jar with the pencil.
5.Label your jar as to the type of solution.
6.Cover the jar with a piece of paper towel to control the rate of evaporation. Set aside in a place where it will not be disturbed.
7.Repeat above procedure with each substance. You should have 4 jars, one for each type of substance used. Label each.
8.Observe daily. Record your observations. Draw what you see.


As the water evaporates, the substance will come out of solution and begin to grow on the thread. This process can take days, even a week. Each crystal will look different. All 4 of these substances are a type of salt: Alum salt, Borax salt, Epsom salt, and Rock salt. As the liquid cools and the water evaporates, some of the molecules in the substance move closer together and join in a repeating pattern. The crystal grows in size by adding more molecules in the same pattern. Each type of crystal has a unique pattern.