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Using baking as a way to see how heat and mixing create something brand new.
Have you ever wondered how a gooey puddle of yellow batter turns into a fluffy, solid cake that you can hold in your hand? It’s not just cooking—it’s a secret chemical reaction!
To make a cake, we start with ingredients. These are the separate parts we mix together. We use dry things like flour and sugar, and wet things like eggs, milk, and oil. When we stir them together, they make a thick, runny liquid called batter. In the batter, the ingredients are all mixed up, but they haven't changed into something new yet! They are just a big, messy puddle of parts waiting for some energy to help them change.
Follow these steps to see how ingredients combine: 1. Pour 1 cup of white flour into a bowl. 2. Crack 1 yellow egg into the flour. 3. Stir them together. Now you have a sticky, gooey mixture that is neither just flour nor just egg!
Quick Check
What do we call the runny liquid mixture we make before we put it in the oven?
Answer
Batter
When we put the batter into a hot oven, something amazing happens. The heat acts like a magic wand! It makes the liquid batter get firm. The eggs and flour cook and stick together to form a solid structure. Tiny bubbles of air get trapped inside, which makes the cake light and fluffy instead of hard like a rock. This change from liquid to solid is caused by the high temperature of the oven, usually around .
Imagine the batter inside the oven: 1. The oven is set to a high temperature of . 2. The heat moves into the liquid batter. 3. The liquid starts to rise and turn into a solid cake that you can slice with a knife.
Quick Check
What does the heat in the oven do to the liquid batter?
Answer
It changes the liquid batter into a solid cake.
Some changes can be undone, like melting ice back into water. But baking is an irreversible change. This means once the cake is baked, you can never turn it back into a pile of flour and a raw egg. The heat has bonded the ingredients together in a brand new way. It’s a permanent transformation! You have created a completely new material that is different from what you started with.
Compare two changes: 1. If you melt a chocolate bar, you can put it in the fridge to make it a solid bar again. This is a reversible change. 2. If you bake a cake, you cannot 'un-bake' it to get the wet eggs back. This is an irreversible change because a new material was made!
Which of these is a dry ingredient used in baking?
What state of matter is the batter before it goes into the oven?
Baking a cake is an irreversible change.
Review Tomorrow
In 24 hours, try to remember: What is the big word that means you cannot change something back to how it started?
Practice Activity
The next time you are in the kitchen, look at a piece of bread. Is it a solid or a liquid? Can you turn it back into dough?