What do these two changes have in common?
adding dish soap to water in a sink
sediment settling to the bottom of a muddy puddle
A: Both are caused by heating.
B: Both are only physical changes.
C: Both are chemical changes.
D: Both are caused by cooling.
Step 1: Think about each change.
Adding dish soap to water in a sink is a physical change. Bubbles may appear if air gets trapped in the soapy water, but a different type of matter does not form.
Loose matter such as sand and dirt is called sediment. Sediment settling to the bottom of a muddy puddle is a physical change.
The sediment sinks, and the water above becomes clearer. This separates the water from the sediment. But separating a mixture does not form a different 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.
Neither change is caused by heating.
Both are caused by cooling.
Neither change is caused by cooling.