Create a delicious centerpiece for Easter as you learn sciecne
When I think of Easter I think of two things, delicious chocolate, and lots of eggs.
In this project, kids can learn about reversible phase changes as they also make hollow chocolate eggs to decorate your table with at Easter dinner.
This is an easy kids project that will delight kids as it makes a bit of a mess, and creates lots of chocolate covered fingers. When you are done I suggest filling the chocolate eggs with other little Easter candies for your table decoration that can double as dessert.
Reversible phase changes can be seen when ice turns to water, and that same water can be turned back into ice.
Here hard chocolate will be turned into melted chocolate that can then reharden as it cools. Not all things go through reversible phase transitions with heat like this. For example, when you heat wood it does not melt, it burns. Thus, when burnt wood cools it does not retake its original structure (that is the look and feel of regular wood. Wood is not a reversible phase change, while the chocolate is.
Read on to get our recipe for homemade chocolate eggs that you can make with your kids!
How to make a hollow chocolate egg with your kids
- Melt candy wafers in a double broiler
- Put the melted chocolate into a piping bag or ziplock bag
- Blow up as many balloons as chocolate eggs you want to make
- Pipe melted chocolate onto balloons
- Allow melted chocolate to harden
- Pop balloons and carefully remove them from the hollow chocolate egg
How to make a chocolate egg
1. Melt candy wafers in a double broiler
Chocolate is very sensitive to heat. If you put your candy melts into a pan on direct stovetop heat they will burn and the oils will begin to clump together. For this reason, when we melt chocolate we melt it slowly over heated water. Heating through the steam, however, introduces its own issues. This is because if water comes into contact with your melted chocolate it will also separate and clump. This is because chocolate is a mix of fats and dry cocoa. When water is introduced the cocoa sticks to the water creating clumps. Trying to mix it all back in is a tough task since fats and water don’t mix.
2. Put the chocolate into a piping or ziplock bag
Don’t cut the tip of your bag until you are ready to begin drizzling the chocolate over the balloons. The warmed chocolate is in liquid form and will flow quickly while it is warm. I like to secure the back of the bag with a rubber band to prevent chocolate from spilling out the top – you never know what will happen in little hands.
3. Blow up balloons as the egg mold
The blown up balloons will act as a mold for the melted chocolate. Each balloon should be blown up to the size of the desired finished egg. I suggest spraying the balloons with cooking spray so the chocolate won’t stick. I totally forgot to do that step and the balloons still pulled away from the chocolate eggs just fine. I do think if you are trying to make an intricate lace looking chocolate egg it might be the difference between success and failure.
4. Pipe melted chocolate onto balloons
This is really a two-person task. The kids can pipe the melted chocolate and the adults can hold and turn the balloons to they get a nice even coverage of chocolate everywhere. You can certainly switch roles, but my neighborhood kids definitely found piping the chocolate more fun.
5. Allow the melted chocolate to harden
Melting the chocolate for our chocolate eggs was the first phase transition (solid to liquid), now we are ready for the second phase transition (liquid to solid). If your kids are asking how this all works, you can use the drying time to talk about how temperature increases the energy between particles, and in this case, allows the chocolate to flow. As the temperature goes down and the particles lose their energy it will harden into a solid. You can also ask them questions like: would this project work with wood? Or cardboard? Why or why not? This gets you talking about the difference between a chemical reaction and a reversible phase transition. With cardboard and wood, the heat causes a chemical reaction that causes it to turn into carbon dioxide, water, and ash. With chocolate the heat causes it to melt, but not to have a chemical reaction, which is why it is still the same delicious chocolate after.
6. Pop balloons and carefully remove them from the hollow chocolate egg
Once the chocolate has hardened you can cut the top of the balloons off and carefully remove them from the inside of your now hollow chocolate egg. Voila! You have a delicious, educational, festive centerpiece for your Easter feast!