Topic
Pressure
7 articles
Chemistry
Why does shaking a fizzy drink make it explode?
Everybody knows a shaken can will soak you, and everybody assumes that shaking somehow pumps it up. Measure the push inside before and afterward and you get the same answer twice. Something else entirely is being changed by all that rattling.
Biology
Why do your ears pop on a plane?
Everything goes muffled, one ear starts aching, and then something clicks and the world comes back. It happens on the way down far more than on the way up, which is a strange thing for a plane to be fussy about.
Biology
Why do your knuckles crack?
Pull a finger and it goes off like a small firework. Try the identical pull again ten seconds later and absolutely nothing happens. Whatever made that noise has to be rebuilt before it can make it again.
Biology
How does a tree lift water to its highest leaf?
The tallest tree alive is taller than a thirty-story building, and the leaves at the very top stay wet all day. No pump ever built can raise water a tenth of that far.
Physics
Why is the back of the fridge warm?
Reach around the back of a refrigerator and the metal is warm. The one machine in the house whose whole job is making things cold turns out to be heating your kitchen, and the reason is sealed inside a pipe.
Biology
How can pushing on someone’s chest keep them alive?
A stranger kneels down and pushes on the middle of someone’s chest, over and over, for ten minutes. No medicine, no machine, nothing fetched. So what is moving in there?
Chemistry
Why does popcorn pop?
A pan of hard yellow beads goes quiet, then starts firing. Nothing is added to it and no kernel gains a single gram. So where does all that white come from?