Making Science Magical: Piece of Cake
Cook Up Some Science Fun
What kid can resist edible science? Kitchen experiments can be the most interesting, because they involve common, everyday household items and yet point out some great science concepts. For example, most children are familiar with cake baking, even if they’ve only watched (and smelled) the process from a distance. They’ve seen cake batter go into the oven and seen the resulting fluffy cake come out after the baking time. Many have wondered exactly how the cake changes from batter to confection, and a surprising number have come to erroneous conclusions like the oven drying the batter out. Help them apply the scientific method and reasoning skills to the process with this simple hands-on experiment that shows why cakes need the ingredients that are in the recipe.
Supplies and Ingredients
Before you present this experiment to children, you’ll want to try it out yourself in the privacy of your own kitchen. Some steps may require a bit of practice, and you’ll want a flawless performance when you are helping kids try the steps in your classroom or group. Here’s what you need to know:
Materials and Equipment Needed:
Small cereal bowl, aluminum foil, pie pan, measuring spoons, small bowl for egg, small mixing bowl, knife to cut cake, timer, oven and mixing spoon.
Ingredients for 4 cakes (amounts shown are for one cake)
6 Tablespoons flour
3 Tablespoons sugar
2-3 pinches baking powder
2 Tablespoons milk
2 Tablespoons oil
1/4 teaspoon vanilla
Cooking oil to grease pans.
Ready, Set, Bake!
Wrap several layers of foil around the outside of the cereal bowl to mold into a small bowl shape. Remove the foil from the bowl and put it in a pie pan for support. Oil the inside of the foil bowl. Make four of these.
Preheat the oven to 350 degrees.
You will make four cakes. One should have all of the ingredients above. Leave the following ingredients out of the other cakes: oil out of one cake, egg out of the second, and baking powder out of the third. Here are general directions for the small cakes, but don’t forget to leave an ingredient out of three of them!
Mix the dry ingredients together. Add the wet ones. Stir until completely mixed. Put the batter into one of the foil pans. Be sure to keep track of which cake is which! Bake for 15 minutes.
When the cakes are done and have cooled enough to handle safely, cut into all four cakes. Look at the insides, and offer tastes of each to the group. While they are looking and tasting, discuss the science that they are noticing. Why did each cake turn out the way that it did?
Getting Down to Science
Cakes “work” because the heat from the oven causes chemical reactions to occur in the batter. Each of the main ingredients in traditional cake recipes is serving an important purpose. By looking at the cakes and matching them up with the missing ingredients, the children will find out what jobs each ingredient is doing. The cake lacking baking powder will be flat and somewhat hard. Baking powder is responsible for making the bubbles in the batter that leave the cake light and fluffy. The cake that has no egg will have a very strange texture because the protein in egg gets harder when heated to help the cake become firm. The cake that has no oil in the batter will be very dry and crumbly, because the oil normally keeps the cake from drying out in the heat of the oven.
Younger children will enjoy simply finding out what function each ingredient in the cake batter serves. Older students can be encouraged to do more in-depth research to discover exactly how each of those ingredients accomplishes its job in the baking process. You can encourage them to conduct additional experiments and present their findings to the group in true science-fair fashion.