Question: Sue wrapped saran wrap which is 0.3 mm thick over the bowl of her toilet and dropped a potato in the middle of it. The potato fell straight through.  She then put down the toilet lid which is 20 mm thick and conducted the experiment again, and the potato bounced harmlessly off the lid. That's because? 
Option 1: the saran wrap is thinner
Option 2: the toilet lid is thinner
Answer: Option 1