Topic
Molecules
9 articles
Chemistry
Why does glue stick?
A liquid goes on, and a minute later two things cannot be separated. The obvious answer involves it seeping into holes and gripping, which cannot be right, because glue sticks perfectly well to a sheet of glass.
Chemistry
Why does wet sand hold its shape?
Dry sand cannot even hold up a small heap. Add a splash of water and the same grains will stand in a tower with vertical walls. Add more water and it collapses into soup, so there is a right amount, and it is far smaller than anybody guesses.
Chemistry
Why can’t you un-fry an egg?
Melt butter and it sets again when it cools. Heat an egg white and it turns from clear jelly to white rubber and stays there forever. Nothing was added, nothing escaped, and in 2015 a laboratory in Australia partly reversed it anyway.
Chemistry
Why does bread go stale faster in the fridge?
The fridge keeps milk drinkable and stops cheese sweating, so a loaf ought to be safe in there too. Instead it comes out hard and crumbly by the second day. Nothing has dried out, nothing has escaped, and the loaf weighs exactly what it did going in.
Chemistry
Why does salt melt ice?
Scatter salt on a frozen step and the ice retreats, even though the salt is exactly as cold as everything else. Nothing has been warmed and nothing has been dissolved away. The salt wins by interfering with traffic you never knew was there.
Biology
Why does a cut apple turn brown?
A whole apple sits in the fruit bowl all week and looks the same on Sunday as it did on Monday. Cut one at breakfast and it is the color of weak tea by lunchtime. Nothing was added to it.
Chemistry
Why do onions make you cry?
A whole onion can sit in the kitchen for a month without bothering anybody. Cut it, and within seconds something invisible has crossed the room to your eyes. It was not inside the onion a moment earlier.
Chemistry
Why does soap get grease off a plate when water won’t?
Hold a greasy plate under a running tap and the water slides off, leaving the grease exactly where it was. One drop of dish soap and it is gone. Nothing burned it away, and nothing melted it.
Chemistry
Why does toast taste different from bread?
Nothing goes into the toaster except a slice of bread, and the slice comes out lighter than it went in. So where does the smell of toast come from?