Changed for Good

Some changes can't be undone: a baked cake, a boiled egg, burnt toast.

Warm-up, learn, try it together, practice, then a quick check. About 15 minutes.

What children learn in Level 34

Some changes can't be undone. Bake cake batter in the oven, and you get a cake. You can never turn it back into batter!
Cook a raw egg, and it gets firm. Cool it in the fridge, and it stays cooked.
Toast can't turn back into bread, and popcorn can't turn back into kernels. The heat made something new.
So there are two kinds of changes: ones you can undo, like melting and freezing, and ones you can't, like cooking and baking.
Your turn! Sort these: can they be undone?

Georgia Standards of Excellence in Science:

S2P1.c — Provide evidence from observations to construct an explanation that some changes in matter caused by heating or cooling can be reversed and some changes are irreversible. (Changes in matter could include heating or freezing of water, baking a cake, boiling an egg.)