You will need:

• Some pieces of chocolate (dark chocolate works best, but you can use milk chocolate too)
• Pan
• Bowls
• Water

What to do:

1. Put water in the pan and place it on the hob.
2. Break the chocolate into small pieces and place it in a bowl over the pan with the water. (See image above.) Be careful not to mix any water with the chocolate.
3. Turn on the hob and gently heat the water with the chocolate and bowl on top.
4. Once the chocolate has melted, turn off the hob.
5. Place half of the molten chocolate in a freezer to cool. If you do not have a freezer, you can use the fridge.
6. Let the rest of the chocolate cool slowly at room temperature.
7. Once both chocolates have frozen, compare what they look like. In addition, test how they taste differently and how they feel to the touch.
8. Although both chocolates freeze and become solid again, they will be very different depending which temperature they are freezing at.

Questions

1. A) Draw a diagram showing the arrangement of the chocolate particles in a solid.  B) Draw a diagram showing the arrangement of the chocolate particles in a liquid.
2. What happens to the energy of the chocolate particles when it melts?
3. What happens to the energy of the chocolate particles when it freezes?
4. How is the chocolate that was cooled in the freezer different from the chocolate cooled at room temperature? Compare how they look, taste and feel when you touch them.
5. The process of melting and freezing chocolate is quite important in food industry and chocolate making. Based on your experiment which temperature do you think is better for freezing chocolate, room temperature or the freezer/fridge? Why?