Cutting onions releases a gas which causes a stinging sensation when it comes into contact with your eyes your body produces tears to dilute the irritant and remove it from your eyes

Cutting Onions: The Science Behind the Tears

Have you ever wondered why cutting onions can bring tears to your eyes? It’s not just your imagination; there is a scientific reason behind this phenomenon. When you slice, dice, or chop an onion, it releases a gas that causes a stinging sensation when it comes into contact with your eyes. This gas is called syn-Propanethial-S-oxide (PSO), and it is responsible for triggering tears.

Our bodies have an impressive defense mechanism to combat this irritant. As soon as the gas reaches your eyes, they start producing tears. These tears serve two essential purposes: they dilute the irritant and remove it from your eyes. It may seem strange that our bodies resort to tears for protection, but it’s an incredibly effective natural response.

When you start cutting an onion, the knife breaks open its cells. This process releases enzymes called alliinases, which then convert the sulfur compounds present in the onion into a gas. This gas quickly evaporates and rises towards your face. Once it reaches your eyes, it reacts with the moisture on your eye’s surface to create the irritating gas, PSO.

The PSO gas triggers the sensory nerves in your eyes, causing them to send a signal to your tear glands. As a result, your tear glands go into overdrive, producing tears to dilute the gas and wash it away. The excess tears then flow down your cheeks, seemingly creating a river of emotions.

Although this tear-inducing reaction can be bothersome, it’s essential to remember that it serves a purpose. Our tear ducts act as a protective shield, preventing the irritant from causing damage to our eyes. The tears effectively flush out the gas, reducing the stinging sensation and providing relief.

To minimize the effects of cutting onions, there are a few tips and tricks you can try. For instance, using a sharp knife and chilling the onion before cutting can help reduce the release of irritants. Additionally, cutting the onion near a draft or under running water can help dissipate the gas more quickly.

In conclusion, cutting onions can be a tearful affair due to the release of a gas called PSO. This irritant reacts with the moisture in your eyes, triggering tear production as a protective mechanism. While it can be bothersome, it’s fascinating to understand the science behind this common culinary occurrence.

Source: Science Bob