Why Onions Make Your Eyes Water

Onions, along with many other plants in the Allium species (garlic is another popular one), absorb sulfur from the soil. When onions are chopped, it ends up breaking cells within the onion, which releases certain enzymes. These enzymes then react with the sulfur, creating amino acid sulfoxides. These, in turn, create the highly unstable syn-propanethial-S-oxide, which is a combination of sulfuric acid, sulfur dioxide, and hydrogen sulfide. When this substance, in a gaseous state, comes in contact with the moisture in your eye, it triggers a burning sensation via the ciliary nerve.


Tears in the eyes are regulated by the lachrymal gland, which is situated just above your eyelids. When the brain gets a message that there is an irritant in the eye, such as the above syn-propanethial-S-oxide, which gives a burning sensation, it then kicks the lachrymal glands into overdrive, trying to flush the irritant out of your eye(s) with tears.


Cooked onions won’t produce this same effect because the process of cooking the onion inactivates the enzymes needed to make the syn-propanethial-S-oxide. So you can safely chew the cooked onions without getting teary-eyed.


Best Ways to Stop Onions From Making Your Eyes Water
1-Refrigerate the onion at least 30 minutes before cutting. Alternatively, put the onion in ice-water for a few minutes before cutting. By cooling the onion, you will slow the enzyme/sulfoxides reaction rate, minimizing the syn-propanethial-S-oxide production.
2-Turn a fan on, blowing across the onions and away from you.
3-Run water over the onions as you cut them. The syn-propanethial-S-oxide that cause the eye irritation is water soluble, so can simply be washed away before having a chance to get in the air.
4-Cook onions often. Research has shown that the more you cut onions up, the less the sulfuric compounds will affect your eyes.

Sources:

• What is the chemical process that causes my eyes to tear when I cut into an onion?
• syn-Propanethial-S-oxide
• Why Do Onions Make You Cry?
• Kitchen Science 101

Liquids Sculptures

Since the beginning of time, water has been an omnipresent symbol in all cultures around the world. Fountain of life and youth, water with its miraculous powers changes shapes and colors, transforms itself. Due to its symbolism and capacity to flow, water becomes a model out of which all kind of things can be born. Even water sculptures.

Martin Waugh, an amazing artist with a degree in physics, tries to captures the most beautiful shapes water can create when in motion. He combines art and science to photograph its movement by constantly changing the size and color, viscosity and surface tension, speed and position of the water drops.

“Fluids in motion fascinate my senses. I feel their smooth and effortless curves: structures reflecting a perfect balance of dynamic forces. They tickle some faint physical memory, like a scent evoking a forgotten mix of feelings.” Martin Waugh

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