Why Do Onions Make You Cry?

Hey, I'm home! Wait... are you crying?

Ugh, it's these onions! I can't see anything!

Oh no! Okay, put the knife down for a second.

Seriously, why do onions always do this to me?

Actually, it's some pretty cool science!

An onion is full of tiny cells, like little bags.

When you cut it, you break those cells open.

That lets two chemicals mix together,

and they make a gas that floats up into the air.

And then the gas goes straight into my eyes?

Exactly. It irritates the surface of your eyes.

So your eyes make tears to wash it away.

Hmm, so crying is my body protecting me?

That's right! Your eyes are just doing their job.

Well, I wish they'd do it a bit more quietly!

Okay, so how do I stop it?

First, put the onion in the fridge for half an hour.

Cold onions release the gas more slowly.

And use a really sharp knife,

because a blunt knife crushes more cells.

What about holding bread in my mouth? My mom always does that!

Ha, sadly there's no real proof that works.

Oh, and leave the root end until last,

because that part has more of those chemicals.

And open a window, or turn on the fan.

Okay, cold onion, sharp knife, window open. Here goes!

Wait... this is actually so much better!

See? Science wins again!

Thanks! Now you can chop the garlic.

Ha, nice try! Garlic doesn't make anyone cry!