What do these two changes have in common?
melting wax
picking up a paper clip with a magnet
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.
Melting wax is a change of state. So, it is a physical change. The wax changes from solid to liquid. But it is still made of the same type of matter.
Picking up a paper clip with a magnet is a physical change. The paper clip sticks to the magnet, but it is still made of the same type of matter.
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.
Wax melting is caused by heating. But picking up a paper clip with a magnet is not.
Both are caused by cooling.
Neither change is caused by cooling.