Topic
Gases
6 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.
Chemistry
Why does blowing kill a candle but feed a fire?
One breath ends a birthday candle. The same breath, aimed at a campfire, makes it roar. Nothing about your lungs changed in between, so the difference has to be hiding inside the two fires.
Physics
Why does helium make your voice squeaky?
Everybody says the gas puts your voice up high. Record it and measure it, and the note you are singing has hardly moved at all. Something else about you got smaller, and it was not your voice.
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.
Astronomy
Why is Venus hotter than Mercury, when Mercury is closer to the Sun?
Mercury sits nearer the Sun than any other planet, so it ought to win. It does not, and the planet that beats it is almost twice as far out. Distance turns out to be the least interesting part of the story.
Chemistry
Why does a cake need baking powder?
Leave it out and the cake comes out flat and heavy, and nothing else in the bowl has changed. So what is half a teaspoon of white powder doing that a pound of flour, sugar, butter and eggs cannot?