If you cut an onion, you begin crying. Have you ever wondered why this happens — why onions make tears run down your face?
Well, onions contain a oil, which has lots of sulphur in it. When you cut the onion, this oil is released. It evaporates very fast. When the oil gases reach your eyes, it causes irritation and sends signals to your tear gland to produce tears. So that the tears can wash away the irritant from your eyes.
Actually the tear glands produce tears all the time. But, that is a very small amount — about a quarter teaspoon a day, to keep the eyes moist. The tears help wash away bacteria and other foreign particles that enter the eyes.
When you cut onions, the onion oil gases enter your eyes. It irritates your eyes and your tear glands produce extra tears to clean it. Then the excess amount runs down your face and the irritant is also removed along with it.
See, how your body has its own way of cleaning itself!
The tear gland is present near the nose on the lower eyelid. You can see it if you go close to a mirror. It has a tiny hole on it. This is where the tears come from.
If you want to cut onions without crying, try this. Cut onions under water. The water will wash away most of the oil present in the onions. And, you can save those precious tears!