How many smells can you identify? Which ones are your favorites and which ones do you really not like? Stop and make a list, because it’ll be an amazingly long and diverse list.
As it turns out, adults can distinguish around 10,000 different smells. And these smells not only trigger our memories but can also change the way our foods taste. (Give this classic apple vs potato experiment a spin.)
From journalist Rose Eveleth and animator Igor Coric, find out how powerful your nose is and what’s going on inside of it in this excellent TED-Ed: How Do We Smell?
There’s more TED-Ed in the archives.
In this extraordinary adaptation strategy, Thailand’s Moken sea gypsies can see twice as clearly underwater by controlling the size of their pupils. What was generally considered an automatic reflex for the rest of us is now thought to be something that any child under 5 could learn how to do.
From a study called Superior Underwater Vision in a Human Population of Sea Gypsies by Dr. Anna Gislén:
The Moken may learn to do this due to their extensive use of their eyes in water, where accommodation and concurrent pupil constriction is necessary for them to see the items they gather for food. It should then be possible for all humans to learn to see better underwater. But because sea gypsies have lived by and off the sea for thousands of years, evolution may also have favored those who had intrinsically better underwater accommodative powers. The ability to see well underwater could have become a genetic trait. Another possible explanation is that accommodation underwater is a side effect of the diving response; the parasympathetic nerves that control this reflex also control pupil constriction.
Read more at National Geographic.
In the archives: more swimming and these extreme eye closeups.