Day Four: Activity Four

Why did the balloons get bigger when the pump was turned on?
The balloons got bigger when the pump was turned on because it was putting pressure on the balloons making them expand.  The pumps job is to move molecules, take them out.  So it was trying to pulling the molecules in the balloons out therefore they expanded.

What was happening at the molecular level?
The molecular level would be rising, because the molecules are moving more and expanding.