How to Grow Salt Crystals

You can make salt crystals from either table salt or Epsom salt, and each forms crystals of a different shape. Use food coloring to make your crystals dazzling and colorful.

Difficulty: Easy

Instructions

Things You'll Need:

• Charcoal Briquettes
• Food Coloring
• Glass Bowls
• Glass Jars
• Spoons
• Pencils
• Paper And Binder Clips
• Paper Towels
• Pencils
• Paper Towels
• Cotton String
• Fishing Weights
• Pencils
• Paper towels
• Glass jars
• Spoons
• 1-1/2 c. Epsom salts
• 1/2 c. table salt
• 2 tbsp. rock salt

Table Salt

1. Boil about 1 c. water.

2. Pour the water into a glass jar.

3. Stir in the salt slowly, about a teaspoon at a time. Don't rush this step.

4. Continue until the salt is no longer dissolving but is starting to collect at the bottom of the jar.

5. Choose a color for your crystals and add a couple drops of food coloring.

6. Tie one end of piece of a string around a pencil and tie a paper clip to the other end.

7. Place the pencil over the jar so that the string hangs down and the paper clip almost touches the bottom of the jar.

8. Allow jar to sit someplace where it will be undisturbed.

9. Check after about 24 hours, and you'll see crystals forming in cubical shapes on the paper clip.

Epsom Salt

10. Follow steps 1 through 4 above, substituting Epsom salt for table salt, and using a glass bowl instead of a jar.

11. Choose a color for your crystals and put a few drops of food coloring on two charcoal briquettes.

12. Place charcoal briquettes in the bottom of the bowl.

13. Allow bowl to sit someplace where it will be undisturbed.

14. Check after five days, and you'll see crystals growing in the shape of prisms.

Tips & Warnings

• You can use other items instead of a paper clip as the "seed," or area where crystals start growing, such as a fishing weight.
• You can substitute rock salt for table salt.
• If the string hanging from the pencil is too long when you place it in the solution, just roll the pencil between your hands until the string wraps around it and the piece of string hanging down becomes shorter.
• Place a paper towel over the top of the jar to keep dust from getting into the crystals.

[gsm137]

on 6/28/2009 The surface of the charcoal is covered in tiny holes which act as a nucleation site. The food colouring is mostly for show, but the fact that the crystals show absorbtion of the colour indicates that they contain "water of crystallisation".

[6daughters4me]

on 5/18/2009 What effect does the charcoal and the food coloring have upon the experiment? How scientific is it to include food coloring, I assume it's just for show. But the charcoal- I really wonder what the effect of the charcoal is. I think we'll do it with and without- I'm a learn-by-reading kind of girl, I wish you would have addressed the reason for the charcoal.

[judefarra]

on 11/13/2008 im making two diffrent ones i didnt get it so one i put 1 table spoon of salt and the other one 2 tablespoons i will tellyou how it goes lol one is blue and one is orange

on 1/25/2006 If you're doing a science fair project, you might want test out your experiment a couple of times before your final. Sometimes your results on the first experiment are less accurate.

on 3/24/2008 Salt crystals will grow up the sides of the jar as evaporation proceeds. After the water cools down, smear waxy lip balm or petroleum jelly around the inside of the rim, above the water line.