Arguing About Reversible Changes Practice Test

Juice freezing is not reversible because it is sticky. Pancake cooking is reversible because it is flat. Crayon melting is not reversible because crayons are colorful.

Juice froze in the freezer, pancake cooked on the pan, and crayon melted near a heater. We tried heating and cooling. Those are the steps we did.

Juice freezing and crayon melting can change back, but pancake cooking cannot. We warmed the frozen juice and it became liquid again, and we cooled melted crayon and it became hard again. Cooling the cooked pancake did not turn it back into batter, so it cannot change back.

All three can change back because we can heat or cool them. Pancakes can become batter again if we mash them. That proves the change is reversible.