Eye-Opening Facts About Tears

Humans make three different versions of tears. Basal tears lubricate our eyes, reflex tears form in response to irritants such as smoke and dirt, and emotional tears flow when we’re sad or overjoyed.

- Jen McCaffery

1 All are made of salt water mixed with oils, antibodies, and enzymes, but they each also contain different molecules. Emotional tears, for example, carry protein-based hormones, including leucine-enkephalin, a natural painkiller released when the body is under stress.

2 onion tears are obviously of the reflex variety—but what’s the irritant? It turns out onions secrete a compound to deter predators—aka some hungry human wielding a blade— called lacrimatory factor. To cut down on its release, refrigerate the onion before slicing, then use a sharp knife to reduce the damage to the onion and the release of the compound.

3 The Latin word for a tear, lacrima, is at the root of scientific tear-minology. Tears are generated in the lacrimal gland, which sits above the eye just under the eyebrow. And the word lachrymist is used to describe someone who tears up a lot (also known by the unscientific term crybaby).