Crying is almost inevitable when you chop an onion.
A chemical reaction takes place when they are cut, and the fumes cause many people to tear.
To prevent it, some wear goggles, while others cut onions under water.
There are those who also swear by clipping your nostrils shut with a clothes peg.
My secret to not crying during the chopping process is a sharp knife and keeping the root intact - don't chop it off.
Watch this video to see how it's done.