What do these two changes have in common?
snowflakes forming in a cloud
water boiling on a stove
A: Both are caused by heating.
B: Both are chemical changes.
C: Both are only physical changes.
D: Both are caused by cooling.
Step 1: Think about each change.
Snowflakes forming in a cloud is a change of state. So, it is a physical change. Liquid water freezes and becomes solid, but it is still made of water. A different type of matter is not formed.
Water boiling on the stove is a change of state. So, it is a physical change. The liquid changes into a gas, but a different type of matter is not formed.
Step 2: Look at each answer choice.
Both are only physical changes.
Both changes are physical changes. No new matter is created.
Both are chemical changes.
Both changes are physical changes. They are not chemical changes.
Both are caused by heating.
Water boiling is caused by heating. But snowflakes forming in a cloud is not.
Both are caused by cooling.
A snowflake begins to form when a tiny drop of liquid water in a cloud freezes. This is caused by cooling. But water boiling is not.