One of the easiest ways to demonstrate science in the home is in the kitchen. Today we are making pancakes to explore some new concepts.
What you need:
Pancake batter, we used the recipe below but you can use any mixture you want.
110g plain flour
Egg whites whisked.
Sift the flour and add the egg into it, whisk the egg into the flour with a splash of milk.
whisk in the rest of the milk.
We are testing 4 different mixtures
- Basic pancake mixture.
- Basic pancake mixture with a teaspoon of baking powder.
- Basic pancake mixture with some whisked egg white.
- Basic pancake mixture with baking powder and whisked egg white.
The baking soda and egg white should add air to the mixture giving it more volume than the basic mixture. Therefore I would expect the pancakes to vary in size. The smallest should be the basic mixture and largest the mixture with baking soda and whisked egg white.
The Science Bit
The baking powder acts as a leavening agent. This means it adds bubble of gas ( Carbon dioxide ) to the dough. This is a chemical reaction which happens when the baking powder mixes with the moist dough mix.
The starch in the flour mixes with the water in the dough mixture to form a matrix which then sets leaving the holes left by the gas bubbles inside. If you don’t use baking powder in the pancake you will get a much flatter one.
Baking powder is an example of a chemical leavener. An example of a biological leavener is yeast.
The egg whites are just another way to add air to the pancake mixture, when whisked the egg whites trap air, increasing the volume of the egg whites. When carefuly mixed into the pancake mixture air is added to the pancake mix too.
Did you know that citric acid (found in lemon juice) stimulates your taste buds? Try adding some to your pancake.
These photos were taken with a microscope. You can clearly see the air bubbles in the mixture with baking powder.