Some oil sinks below the surface. Oil droplets form in the water. The oil and water mix together. The oil floats on top of the water.
I gave my students this multiple choice question: What happens when oil is placed in water?

Only one answer is correct among these 4 choices:
- Some oil sinks below the surface.
- Oil droplets form in the water.
- The oil and water mix together.
- The oil floats on top of the water.

Could you tell me which one is correct?

The oil floats on top of the water.