Science Experiments for Kids
open menu
open search bar
×

Rock Candy Recipe

By 31 Comments

The first thing I have to say about this activity it that it’s sticky, messy and doesn’t always work, but when it does it’s pretty amazing. Our rock candy recipe has been perfected from many, many attempts to get it to work, so hopefully we’ve done most of the hard work for you.

The first time we tried nothing grew at all as the solution wasn’t concentrated enough, the second time we made it too concentrated and the whole solution crystallised. The third time it worked!!

Rock Candy Recipe

3 cups of caster sugar

1 cup of water

A lolly stick or circle of wire. Or some string.

A Jar,

Sellotape

Some sparkles  and/or food colouring ( optional )

Rock Candy Instructions

Dissolve the sugar in the water, as soon as it’s dissolved, remove the heat and leave to cool a little bit. If you can get a bit more sugar to dissolve then thats a good thing. You want a saturated solution.

Pour the solution into a glass jar and suspend the lolly stick, we used some sellotape to hold it in place. Don’t let it touch the bottom or the sides or the jar.

Alternatively you could tie some string to a pencil and rest the pencil on top of the jar with the string hanging in the jar.

You should see crystals start to form after a few days.

We made a lolly and a circle to hang on the Christmas tree. I was a bit disapppointed with the circle, but we will be trying again with a star!

Why does sugar crystallise?

A crystal is a solid material with a naturally geometrically regular form. Some take millions of years to form, such as diamonds. The sugar crystals we made above take just a few days.

Most minerals dissolved in water will form crystals given enough time and space. The shape of the crystal formed depends on the mineral’s molecule shape.

In the case of our sugar crystals there are two process at work.

Evaporation – the water evaporates slowly meaning the solution becomes more saturated, so the sugar molecules come out of solution and collect on the string/wire or stick.

Precipitation – the solution we made was very concentrated which means there was too much solute to remain dissolved in the water, therefore it starts to precipitate.

Sugar crystal lollypops

 

Safety Notice

Science Sparks ( Wild Sparks Enterprises Ltd ) are not liable for the actions of activity of any person who uses the information in this resource or in any of the suggested further resources. Science Sparks assume no liability with regard to injuries or damage to property that may occur as a result of using the information and carrying out the practical activities contained in this resource or in any of the suggested further resources.

These activities are designed to be carried out by children working with a parent, guardian or other appropriate adult. The adult involved is fully responsible for ensuring that the activities are carried out safely.

Reader Interactions

Comments

Trackbacks

Leave a Reply

Your email address will not be published. Required fields are marked *