Rock candy is one of the oldest treats around, and it's simple to make. It also makes a great science project and is often used to teach about crystals. You can talk to kids about minerals and atoms and ions, or you can help them cook up a batch of rock candy and let them see crystals forming in real time. Plus, this is a really fun (and edible) project.

Kids will be delighted to find out that they've got crystals right in plain sight in their kitchen -- sugar and salt. When they boil sugar and water together, they're creating a super-saturated sugar solution. Basically, there's more sugar in the solution than it can hold, so the crystals begin attaching themselves to the cotton string.

Over time, water evaporates from the solution so the sugar continues to attach itself to the formation. Eventually, kids end up with a string full of beautiful sugar crystals that they can study, then eat.

Want to get started on this interesting experiment? Check out the gallery below!