Science Experiment – Salt Crystals

By AG Education 4 September 2017
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If you start now, you’ll have crystals in a week!

Creating Crystals

With a few simple items, you can start a proces that will create salt crystals all along a string. Crystals are organised groupings of molecules, and as the water evaporates sodium and chlorine atoms will bind together, forming cubic crystals. Make sure you get an adult to help you with this one, especially when dealing with hot water!


  • 3 cups of table salt
  • 1 litre of water
  • Pencil
  • Paperclip
  • A short length of string
  • A very strong plastic (or pyrex) jar – do not use a glass jar for this, since it could break


  1. Boil the water
  2. Pour the hot water into the plastic jar.
  3. Add the salt in teaspoons, allowing it to dissolve before adding the next.
  4. Continue adding the salt until it no longer dissolves, and it begins to collect at the bottom of the jar.
  5. Tie one of the string around tightly to the middle of the pencil, and the other end to the paperclip.
  6. Dangle the paperclip in the water so that it is completely submerged but doesn’t touch the bottom of the jar – spin the string around the pencil if you need to shorten the string.
  7. Allow the jar to sit undisturbed for the rest of the week – and watch your salt crystals start to form at the top of the string.

When you mix the vinegar and bicarbonate of soda, they react together to make a gas called carbon dioxide. The gas builds up inside the bottle until it forces its way out the top. Beneath the Earth’s crust, magma, a mixture of rock and gases, sometimes does the same thing. It rises up through cracks in rocks and bursts out as lava.

Do you want to keep learning? Find more experiments here!