Why do Cakes Rise?

During Science week 3CW & 3CO made Fairy cakes in a Halogen oven. They took turns reading, measuring, adding and mixing ingredients.

3CW put bicarbonate of soda and water into a jug and heated it in the microwave. They watched and listened to the fizzing.

Now the science part: cakes rise because the baking soda reacts with acidic ingredients to produce tiny bubbles of CO2 that get trapped in the cake mixture. When heat is added, the air bubbles expand and the cake rises while baking.