Watch the inside of an already divided onion with a magnifying lens, you will see
Small, tiny sacs attached to each other like that of an orange or grape. Inside the sacs lies a juice which spills open when the onion is cut

open. The juice emits[b]Propanethiol S-oxide[/b] gas which reacts with an enzyme in the onion to emit a
passive sulfur compound. Our tear ducts react by
releasing tears (when blinking) to flush out the
sulphuric acid.

Here are some means by which you can prevent the tear in the eyes:

Use a very sharp knife when cutting onions .
The enzymes are released when cells are
broken or crushed; using a sharp knife slices
through the onion rather than crushing and
thus, fewer enzymes are released.
Chill the Onions

Chill your onions in the freezer for 10 – 15
minutes before cutting them.
This reduces the
amount of the acid enzyme released into the
air. This was found to be the most effective
way to reduce tears by the television program
Food Detectives.
Avoid Getting The Gas In Your Eyes

Wear gas tight goggles or a mask .

Cut the onion next to a strong draft from a
fume hood or fan.
This is so that the gas is
pulled away from your eyes

Wear contact lenses.
They create a barrier between the surface of your eyes and the gas. Absorb The Gas In Water

Cut the onion under water .
Cut the onion near running water or a cloud of
steam. Steam from a kettle or pan of water
will do the trick.
Soak the onion in water . The enzyme is
denatured by the water-air boundary.

Breathe through your mouth
(to draw the gas over your wet tongue) or stick your tongue out .
Breathing through your mouth will make the olfactory nerves, which are closely located to the tear duct nerves, will be by bypassed and there will be no tears generated. This is easily confirmed when you forget and breathe through your nose. Instant tears.

Put vinegar on the chopping board.
The acid denatures the enzyme.

Soak the onion in salt water .
The ionic solution denatures the enzyme.
Other Methods

The candle method.
Light a candle and set it
near the cutting board before cutting the
onion. The gas released by the onion is drawn
into the flame of a candle.

Pay attention to air direction

Whistle while you work.
Whistling increases airflow, specifically away from your
face, which keeps the onion mist away from
your eyes. Just pick a catchy tune that you
won’t want to stop whistling and you can cut
as many onions as you need.

Check this methods out and report back to us.
Thank you

SOURCE:
http://www.naijanovaz.com/why-does-onions-make-me-cry.html

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