Materials:
Construction Paper
Scissors
Plate or shallow bowl
Warm water
Epson Salts
 
1. Use scissors to cut out the paper so it will fit in the bottom of your plate.
2. Add 15mL of Epson salts to 60mL of warm water.  Stir until the salt dissolves
3. Pour the entire salty water onto the black paper in the pie pan.  (You can add a few drops of food colouring to the mxture)
4. Put the plate into the sun.  When the water evaporates, you’ll see lots of crystal spikes on the paper.
 
Why does the Epson salt make spikes?  When you add Epson salt to water, the salt dissolves.  When you leave the pan in the sun, the water evaporates and the salt forms crystals shaped like long needles.  If you treid theis experiment with table salt wouldn't get crystal spikes.  That’s because table salt and Epson salt are chemically different, so the crystals that they form are very different.