【明報專訊】Have you ever put a slice of lemon or lime in a cup of water? A lemon slice floats while a lime slice sinks to the bottom. The reason is that limes are denser than water, and the density of lemons is very close to that of water.

“ Bill: Like lemons, I can float on water easily! ”

■Glossary

lime (n) 青檸

float (v) 浮

density (n) 密度