A: It's so hot! Let's go swimming now!
B: We have to wait a while before swimming.
A: But why? The sun is so hot!
B: It's bad to swim after you just ate.
A: Why? Will you sink in the water?
B: No. The motion and sudden cold will make you sick.
A: What kind of sick?
B: It can make you nauseated, and you might throw up.
A: How long do we have to wait?
B: Only about half an hour.
A: Half an hour?! I'll bake in the sun!
B: It's better than throwing up your lunch!