Crystal Creations

 One hour or more

what do I need?

  • Black construction paper
  • Scissors
  • A pie pan, cake pan, or shallow bowl
  • Warm water
  • Epsom salt (usually near the rubbing alcohol in the supermarket)
 Father and son prepare experiment

1 Use your scissors to cut the black paper so it will fit in the bottom of your pie pan.

 

Trimming paper

 

 

Tips for Home Scientists: This activity works best on a sunny day.

 

 

 

2 Add 1 tablespoon of Epsom salt to 1/4 cup of warm water. Stir until the salt is dissolved.

 

 Pouring the water onto the paper

3 Pour the salty water onto the black paper in the pie pan.

 

 

4 Put the pie pan out into the sun. When the water evaporates, you'll see lots of crystal spikes on the black paper!

The sun shining on the pan

 

 

 

Try this!

The Mudd family discovered that these crystals look great under a microscope.

What's going on?

Why does Epsom salt make crystal spikes?

When you add Epsom 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 tried this experiment with table salt instead of Epsom salt, you wouldn't get crystal spikes. That's because table salt and Epsom salt are chemically different, so the crystals that they form are very different.Photo of salt crystal art

The picture on the right shows part of an artwork created for the Exploratorium by Swiss artist Jörg Lenzlinger. He mixed different kinds of salts with water. As the water evaporated, the salts crystallized, making beautiful shapes that kept growing and changing.

To learn more about this salt crystal artwork, visit our Complexity website.


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This and dozens of other cool activities are included in the Exploratorium's Science Explorer books, available for purchase from our online store.

About the Books

Published by Owl Books,
Henry Holt & Company, New York,
1996 & 1997

ISBN 0-B050-4536 & ISBN 0-8050-4537-6,
$12.95 each






© 1998 Exploratorium