How to Grow a Salt Crystal

Growing sodium chloride salt crystals is a fun and easy science project for kids and a great way to give them their first taste of the science of salt.

Children Experimenting with Salts

It takes a few days, but by growing the crystals, you’ll see how solutions are made and how the crystalline shapes of salt is formed.

Take Care! The teacher should demonstrate this experiment which uses boiling water. Children should not be permitted to handle the jars until the water has cooled to room temperature.

What You’ll Need

To grow your own salt crystals you’ll need:

  • Table salt – sodium chloride
  • Distilled Water
  • A clean, clear glass container – a jam jar is perfect
  • String
  • A spoon for stirring.

What To Do

Here’s what to do:

  1. Stir salt into boiling hot water until no more salt will dissolve (crystals start to appear at the bottom of the container). Be sure the water is as close to boiling as possible.
  2. Carefully pour the solution into your jar. (putting a spoon into the jar before adding the water should prevent the jar breaking.
  3. Suspend your string into the jar from the spoon laid across the top of the jar.
  4. Leave your jar somewhere it will not be disturbed and wait for your crystal to grow!

What To Look For

Once your crystals have grown, here are some things for you to look for in them:

  • Any impurities in the salt or the water will change the shape and colour of the crystals you grow. What shape and colour are yours?
  • Try using different types of table salt – try iodized salt, un-iodized salt, sea salt, or even salt substitutes. Is any difference in the appearance of the crystals?
  • Try using different types of water, such as tap water compared with distilled water. Is there any difference in the appearance of the crystals?
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