James Elkins, USA

I grew up in a house next to a huge, bowling-ball-shaped pond. The water was always stagnant, and the mud at the bottom was half-liquid, and deep. In the summer it was choked with algae, and we often saw fish floating dead on the surface.

There's a kind of algae called "maiden's hair" or "angel's hair," that grows in thick strands. If you pick up a clump it stretches and breaks, like thin overcooked vermicelli. My mother had always said I had "feminine" hair, and she said it was as smooth as angel's hair. As I remember, I was always a little insulted by that, but I also loved it because it tied me to something outside, in nature.

When I was about ten years old, my father brought out his school microscope, and showed me how to look at things like the scales on butterfly wings. I still remember when I discovered what maidenhair really looks like. Its stalks are translucent and glossy, like old-fashioned cellophane, and it has deep green spirals inside, lumpy and ripe-looking. (Its scientific name is Spirogyra, "helix.") When Spirogyra mates, two strands come side by side and a bridge oozes out between them. Sometimes cells burst and release tiny swimming eggs, with little hairs to guide them. I was captivated by all that, and it started my interest in science. My own hair under the microscope was brittle and dead-looking, and I still think of it that way.