Homemade Candy Recipe - Homemade Rock Candy

Here's a great at home or in the classroom science experiment that kids will love because they can eat it to!

If you are looking for more homemade candy recipes then dont forget to visit our Candy Recipes Page

If you really want to capitalize on the learning opportunity here, follow the precooking steps. Otherwise skip right to the home made candy recipe below, or this video on how to make your own rock candy

Precooking

1. Write down predictions about what will happen to the sugar during the experiment.



2. Have a piece of paper with a line down the middle.



3. On one side the child should use a pencil to draw the sugar crystals as they appear through a magnifying glass.



4. Leave to other side of the paper blank and the child can draw the rock candy once it is finished.



5. Have the child write about how the two pictures look the same or different and why.

Your Homemade Candy Recipe

Ingredients:

4 cups sugar, 2 cups water, Food Coloring

Materials:

• Small saucepan
• wooden spoon
• Candy thermometer
• Pint size clean glass jar
• Measuring cup
• Cotton string
• A weight to hang on the string - such as a screw or galvanized washer 
• Waxed paper
• Pencil or wooden dowel(to suspend the string in the jar)

 

Method

1. Heat the water in the saucepan over medium-high heat until it comes to a boil.



2. Completely dissolve the sugar in the boiling water, stirring continuously with the wooden spoon until the solution grows clear and it reaches a rolling boil.



3. Remove the solution from the heat, and then carefully pour it into the jar. Cover the jar with a small piece of waxed paper.



4. Tie the weight to one end of the string, and then tie the other end to the middle of the pencil. The string should be about two-thirds as long as the jar is deep. Dip the string into the sugar solution, remove it, lay it on a piece of waxed paper, straighten it out, and let it dry for a few days.



5. Gently suspend the prepared string in the solution and let sit at room temperature, undisturbed, for several days. You can check each day to see how much your crystals have grown. It's tempting, but don't touch the jar until the experiment is finished - it usually takes about seven days.



6. At the end of the week, the crystals on your string should be clearly defined, with sharp right angles and smooth faces of various sizes.

Homemade candy recipe information for discussion and teaching

Why do the sugar crystals form into rock candy in this way?

Two systems are at work here to cause the sugar crystals to form.

First, you have created a supersaturated solution by first heating a saturated sugar solution (a solution in which no more sugar can dissolve at a particular temperature) and then allowing it to cool. A supersaturated solution is unstable - it contains more solute (in this case, sugar) than can stay in a liquid form - so the sugar will come out of solution, forming what's called a precipitate. This method is called precipitation.

The other is evaporation - as time passes, the water will evaporate slowly from the solution. As the water evaporates, the solution becomes more saturated and sugar molecules will continue to come out of the solution and collect on the seed crystals on the string. The rock candy crystals grow molecule by molecule. Your finished homemade rock candy will be made up of about a quadrillion (1,000,000,000,000,000) molecules attached to the string.

Vocabulary

In most states students are expected to have an understanding of these words and concepts by fourth grade.

Supersaturated, Solute. Evaporate, Evaporation, Precipitate, Precipitation.

Video On How To Make Your Own Rock Candy