Boxi Learn › Biology › Stage 3 · Structure and Evidence
Why are cells so small?
BIO-2 Structure fits functionX-1 Guess, then check
What many people think
Big animals have bigger cells.
The idea
When a cell doubles in width, its volume grows eight times but its surface only four, so big cells cannot feed themselves.
Explain it
A friend says an elephant must have huge cells. Using the cube model, explain why a cell twice as wide gets hungrier faster than it can feed, and what an elephant does instead.
Try at home
Put a big ice cube and the same amount of crushed ice in two glasses of warm water. Which melts first? Heat gets in through the surface, like food into a cell.