Most metaphors in biology are qualitative and vague. "DNA is the blueprint of the cell." OK but, like, how big is that blueprint? For our latest essay, @ClamonsSam gives a bunch of QUANTITATIVE metaphors to help you understand the sizes of biology, from molecules to cells. He imagined that each water molecule in a cell was blown up to the size of a grain of sand, and then calculated what that would mean for everything else. At this scale: 1. A typical protein would now be a knobby ball the size of a blueberry. 2. An antibody would consist of three blobby arms, each roughly the dimension of a grain of basmati rice, connected to a common center by a short chain. 3. A typical human chromosome would be a thread of double-stranded DNA about 100,000,000 bases long, which is just long enough to span the English Channel (34 km). 4. A human virus is now the size of a ping-pong ball. 5. A mitochondrion is as wide as a cow. And there are so many more metaphors in this essay. We think it could be a valuable resource for schoolteachers and students who are looking to "grok" the scales of things in biology.