Chocolate and Lego

Chocolate and Lego: it sounds like the perfect plan for the afternoon. In this activity you will learn more about chocolate and use Lego walls to help us understand why chocolate can lose its snap. In the hands-on activity, you will heat and cool chocolate to see how this changes what the chocolate looks, sounds and tastes like. Finally, we will be introduced to something called polymorphism, which will help us understand what is happening to the chocolate, by building Lego walls.

What Makes Chocolate Snap?

Watch the Chocolate video on the right. Subtitles are available by clicking on the icon.

Once you have watched the video, why not try the activity yourselves by downloading our recipe and instruction sheet?

Download the Instructions

The PDF below contains instructions including what is needed to complete the activity, step-by-step instructions, and a health and safety guide.

Download the Instructions


What are you seeing?

The molecules in cocoa butter have at least 6 different ways that they can arrange themselves in a crystal. The different ways the molecules can arrange themselves are known as polymorphs and each polymorph might show very different properties. Polymorph number 5 is the desired form in chocolate bars, as it snaps when you break it, it melts in the mouth, and has a glossy, smooth appearance. When chocolate is melted and cooled down again the chocolate bar turns slightly white (this is called blooming) because another more easily grown polymorph of chocolate has formed.


Building Crystals with Lego

In this activity we will use Lego walls to help us understand crystals and polymorphism, the phenomenon that causes chocolate to lose its snap.