States of Matter — Answer Key
Part A: Multiple Choice
Circle the best answer for each question.
1. When butter melts in a warm pan, which change is happening?
A) Gas to liquid
B) Solid to liquid
C) Liquid to solid
D) Solid to gas
Cold butter is a solid. Heat melts it into a liquid, which is a solid-to-liquid change.
2. Water boiling on the stove changes from:
A) Liquid to solid
B) Solid to liquid
C) Liquid to gas
D) Gas to liquid
Boiling turns liquid water into a gas called water vapor, which you see as steam.
3. A frosted cake is put in the freezer. The cake itself:
A) Turns into a gas
B) Becomes a liquid
C) Stays a solid but feels harder
D) Melts into frosting
Cold does not change the cake into a different state; it stays solid but the texture hardens.
4. When cake batter bakes in an oven and rises, which change is NOT reversible?
A) Water evaporating from the batter
B) Gas bubbles forming and expanding
C) Batter baking into a firm cake
D) Pan heating up
Baking creates permanent changes: the batter becomes a firm cake and cannot return to liquid.
Part B: Fill in the Blank
Write the correct answer on each line.
1. Chocolate chips in a warm bowl turn from solid into liquid.
Heat melts solid chocolate into a liquid you can drizzle onto treats.
2. Boiling soup sends hot steam into the air above the pot.
Steam is water vapor, a gas that forms when liquid soup reaches boiling temperature.
3. When juice is placed in an ice pop mold in the freezer, it becomes a solid.
The freezer cools the liquid juice until the water in it freezes into solid ice pops.
4. An ice cube melts into a puddle of water on a warm plate.
Melting changes solid ice into liquid water when the temperature rises above 0 degrees.
5. When popcorn pops, water inside each kernel turns to gas and bursts the kernel.
Water vapor (gas) expands quickly inside the hot kernel, making it burst open.