Do you know why we cry when we slice the onions ?

When we slice onions in the kitchen , are not aware of our eyes shed tears . Now roughly what is it? When the onion is cut using a knife , then the cells in the onion rupture and cause the amino acids in the onion split into sulfuric acid . Sulfuric acid is then reassembled by a particular enzyme , as a consequence will produce gas propanethial s - oxide is volatile . Volatile gas is lifted into the air and reaches our eyes . When entering the eye will activate the sensor neurons in the eye and cause a stinging sensation . Mata then reacted with tears from the tear glands to relieve irritation . So that we do not watery eyes , when we cut onions , we could do it by soaking with water shortly before or during cut . So that the substance is soluble in water and not on our eyes .