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Crystals are made when a substance has atoms or molecules that form in a very organized, repeating, 3D pattern. Usually when we think of crystals we think of some well-known gemstones like diamonds or rubies, but there are some very common crystals too. Sugar, ice, snowflakes, salt…all of these are crystals. You can make your own crystals grow.
- 2 Glasses or Jars
- 1 Plate
- 1 Spoon
- 2 Paper Clips
- Hot Tap Water
- Piece of Yarn or Cotton String, about 6 inches long
- Baking Soda
Fill each glass with water. Add 2 tablespoons of baking soda to each glass. Stir the mixture. If all of the baking soda dissolves, add a little more baking soda and stir. Add baking soda until the water can’t dissolve it anymore, the mixture is saturated. That means the water is holding as much of the baking soda as it can. You can add a few drops of food coloring to each glass to make the crystals colorful. Tie a paper clip to each end of the piece of yarn or string. Drop one paperclip into each glass letting the string dangle in a smile shape in between the glasses but not touching the plate. Watch the string over the next few days to see the crystals form along the string.
The picture on the right shows you what the baking soda crystals will look like after a few days. As the days go by and the water in the baking soda solution evaporates, the level of the water will go down. Make sure the end of the string with the paper clip on it stays submerged in the baking soda water in the glass.
Science Experiment Idea
Grow more than one kind of crystal. Use salt, sugar, and baking soda. Keep a chart as you observe how the crystals grow over the next few weeks. Which one do you think will grow the biggest? Which one will form the fastest?
Here is a video that shows you some super fast crystal growing:
Here are some books and websites that give you ideas for making crystals. You can grow crystals using salt, sugar, baking soda and many other substances.
- San Diego Natural History Museum: Grow Your Own Crystals
- Exploratorium: The Science of Rock Candy
- Exploratorium: The Science of Cooking
- Science Bob: Make Your Own Rock Candy
- Family Fun Crystal Tree
- Scholatic: Homemade Rock Crystal Candy
- Martha Stewart Crafts: Borax Snowflakes
- Baking Soda Stalactites
- Science Rocks! Crystal Creation Pipecleaner crystal snowflakes (pages 16-17)
- Prize Winning Science Fair Projects for Curious Kids – Crystal Creation (pages 81-82)
- Mixtures and Solutions – Solubility Try This! Growing Crystals (page 22-23)
Words to Know:
Crystal – A solid whose atoms or molecules are arranged in a 3-dimensional repeating pattern. Examples: A snowflake, a sugar crystal, a diamond.
Crystallized – The process of crystal growth or crystal formation.
Dissolve – To mix two substances together and have the molecules of one substance spread out between the molecules of the other substance.
Saturated - When a liquid is holding as much of a solid as it can. It has dissolved all of the solid it can hold.