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Toddler Science: Making Rock Candy from Sugar Crystals

Toddler Science: Sugar Crystal Experiment

rock candy DESCRIPTION

Watch crystals grow! Color the water and make them into tasty treats while learning about solids and liquids.


  • 1 cup water
  • 2 - 2 1/2 cups sugar
  • Clear Jar or Cup
  • Food Coloring
  • 1/4 inch dowel

  • Note: We also tried heavy string and a skewer

  • Measuring Cup
  • Spoon
  • Small Pot
  • Coffee filter or muffin tin (optional)
  • STEPS preparing sugar crystals

    1. Clip a thin wooden dowel with a clothespin
    2. Place in jar so that the dowel is about an inch from the bottom and not touching the sides.

    3. Boil water. (Adult Step)
    4. Add 1/4 cup sugar and stir until completely dissolved. (Adult Step)
    5. Keep adding sugar in increments and stirring until it stops dissolving. We used 2 1/2 cups of sugar.
    6. Remove from heat and let cool for 10 minutes.
    7. Pour into clear measuring cup. This makes it easy for your child to view as well as easier to pour into the clear glass jar.
    8. growing sugar crystals

    9. Pour into jar and keep jar in a place it will not be disturbed.
    10. If you plan to eat this, poke a small hole in a coffee filter and push skewer or dowel through it to cover gently.
    11. Crystals should start forming in about three days.

    sugar crystals forming in jar


    Best Set Up

  • We found the dowel worked the best. This can be found in the craft section or in a craft store.

  • We found string to be the most difficult. The white kitchen string floated and the twine touched the glass which caused it to get stuck on the glass.
  • The crystals will be significantly lighter than the color of your water, notice the color of the mixture and the end result of the purple crystals above. On the other hand, if you put too much dye it is harder to see the crystals forming.
  • Results will vary. Seeing the difference between the three samples indicates that success may vary with what type of container you use, whether you use a dowel or string. Temperature in your home may affect how quickly the crystals form as well.
  • Other Tips

  • Do NOT ever completely seal a glass jar containing a very hot fluid. You can risk the jar bursting.

    crystal experiment sequencing
    Take Pictures and Make a Toddler Science Book or Sequencing Cards

    Take pictures of each part of the experiment, mount on construction paper, and have your child put the pictures in order. Make it into a book or use as sequencing cars. Ask your child what happened and write it under each photo.


    How does this work?

    The basic principle behind growing sugar crystals is to saturate the water with sugar to the point where the water can no longer contain all of the sugar molecules. While the water is hot, it can hold more molecules of sugar. When making a sugar solution designed to make crystals, by completely saturating the hot water with sugar until no more can dissolve, makes it possible for the crystals to grow when the water cools. As the water in the jar starts the evaporate, the sugar is extracted from the solution and forms sugar crystals on your skewer/dowel.

    How Long Does It Take?

    Even when the water has been completely saturated, it will take at least a couple of weeks until you get the results shown above. It can take up three or four weeks.

    Why do you use a string or dowel?

    This gives the crystals something to form on and makes it easier to view.



  • Seeing Watching the crystals grow each day.
  • Feelingthe crystals after they form
  • Tasting if you let them taste the crystals...or the sugar before mixing into the water
  • Communication

  • Silent Showing how the sugar is dissolved in the water.
  • Oral Lots of verbal discussion when talking about what is happening throughout this toddler science activity, making guesses as to what will happen, etc
  • Pictorial Looking at pictures of crystals.
  • Comparing

  • Measuring ingredients for the solution
  • Organizing

  • Data Gathering
  • Take pictures every few days.
  • Sequencing
  • Print out pictures and put in order.

    Thanks for stopping by! Comments Are Welcome!

    Check back frequently for newly added Toddler Science Activities!

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