Heating & Cooling Changes

Question 1

Sam did two experiments. First, he placed a piece of ice in a warm room and watched it melt into water. Then he put the water in a freezer and it became ice again. Second, he held a piece of paper over a candle flame. The paper turned brown, got holes, and stayed brown and torn after the flame was put out. Which statement best explains why Sam’s results show that some changes caused by heating or cooling can be reversed while others cannot?

Accepted Answer

The ice melted because heat added energy, and when it was cooled the water lost energy and became ice again; the paper changed because the heat caused a chemical change that cannot be undone.

Answer

The ice melted and turned back into ice because the water was still the same material, while the paper changed because it was a different material than the ice.

Answer

The ice melted because it was in a warm room, and the paper turned brown because it was near a flame; both changes are permanent and cannot be reversed.

Answer

The ice melted because the warm room was hotter than the ice, and the paper turned brown because the candle was hotter than the paper; both changes are the same type of heating effect.

Question 2

Lila left a scoop of ice cream on the kitchen counter. After a while the ice cream turned into a liquid, and when she later placed that liquid in the freezer it became solid again. Which statement correctly describes these two changes?

Accepted Answer

The ice cream melting on the counter is melting (solid → liquid) and the ice cream becoming solid again in the freezer is freezing (liquid → solid).

Answer

The ice cream melting on the counter is freezing (liquid → solid) and the ice cream becoming solid again in the freezer is melting (solid → liquid).

Answer

The ice cream melting on the counter is sublimation and the ice cream becoming solid again in the freezer is condensation.

Answer

The ice cream melting on the counter is evaporation and the ice cream becoming solid again in the freezer is condensation.

Question 3

Which two temperatures correctly tell when water turns into ice and when it turns into steam?

Accepted Answer

0 °C for freezing and 100 °C for boiling

Answer

0 °C for freezing and 90 °C for boiling

Answer

-10 °C for freezing and 100 °C for boiling

Answer

5 °C for freezing and 150 °C for boiling

Try three questions

Lila left a scoop of ice cream on the kitchen counter. After a while the ice cream turned into a liquid, and when she later placed that liquid in the freezer it became solid again. Which statement correctly describes these two changes?

Which two temperatures correctly tell when water turns into ice and when it turns into steam?

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