All four classes weighed the soil and calculated the amount of water lost– so far.

Follow up questions were:

Is there still water in the soil?  (We need to weigh again next week.)

How does the water get from the center of the pile of soil to evaporate?  (As water evaporates, the empty space is connected to the atmosphere– meaning water in the middle of the pile is connected to the atmosphere through pore spaces and can evaporate.)