Rosie Makes: Bread in a Bag

Most of the materials/ ingredients for this project can be found in your home pantry. If you need to order a specific item, we’ve created an easy-to-order Amazon Shopping List.

Chemistry is a branch of science that studies what things are made of and how different substances mix together to make new substances. Chemistry is all around us, and it helps us understand how substances change and react with each other.

When two or more substances mix and create something new, you can tell a chemical reaction is happening if you see things like:

1. Color Change: A sudden or gradual change in color can signal that a chemical reaction is occurring. For example, when iron rusts, it changes from gray to a flaky orange-red.
2. Formation of a Precipitate: Sometimes, when two solutions are mixed, a solid forms. This solid is called a precipitate, and its formation is a sign of a chemical reaction.
3. Gas Production: The release of a gas is another key sign. You might see bubbling or fizzing, like when vinegar reacts with baking soda to produce carbon dioxide.
4. Temperature Change: A chemical reaction can release or absorb heat. If a mixture gets warmer, it’s exothermic; if it cools down, it’s endothermic.
5. Light Emission: Some reactions produce light, like in glow sticks or certain biochemical reactions in living organisms.
6. Odor Change: The production of a new smell can also indicate a reaction, such as the sulfur smell when an egg rots.

These are clues that substances are changing their forms and new substances are being created.

When you make bread, you use yeast, which helps the bread rise and become fluffy.

Yeast is a type of fungus that helps bread dough rise. When you activate yeast, usually by mixing it with warm water and a bit of sugar, it starts to eat the sugar. As the yeast digests the sugar, it produces carbon dioxide gas and alcohol as byproducts. The carbon dioxide gas gets trapped in tiny pockets within the dough, which causes the dough to expand or rise. This process is known as fermentation.

The warm environment helps the yeast work faster, which is why warm water is used to activate it. As the dough rises and bakes, the yeast’s fermentation makes the bread airy and light, while the alcohol evaporates due to the heat of baking.

So, when you make bread in a bag, you’re observing a real chemical reaction right in your kitchen!