New research shows how to cut onions without making your eyes tear up.

A new physics-based study provides useful information to help us avoid tearing up when cutting onions.

Cutting onions can make your eyes sting and water - Photo: AMBITIOUSKITCHEN

According to IFLScience , when cut, onions release aerosols containing the volatile liquid syn-propanethial-S-oxide, which can irritate the nerves in the eyes, into the air and cause our eyes to sting or tear up.

While scientists know why onions make our eyes water, they generally don't fully understand the mechanisms by which these tiny aerosol droplets behave when they are released from onions.

In the new study, Sunghwan Jung, of Cornell University, and colleagues combined high-speed particle velocimetry (PTV) and digital image correlation (DIC) to visualize and quantify the aerosol droplets emitted from cutting onions. DIC is an optical measurement technique that allows for comprehensive analysis of the deformation, displacement, and stress of a material or structure.

The team designed a guillotine-like device with a blade that could be dropped from above to cut the onion. The onion itself was also coated with black paint and left to dry for 30 minutes to allow better observation.

In addition to monitoring the onions as they were cut, the team also used electron microscopy to assess the sharpness of the blades used in the study. These blades varied in thickness, from 5 to 20 mm.

The team found that sharper blades produced fewer droplets at slower speeds. Conversely, cutting onions with a dull knife produced more droplets. In some cases, aerosols emitted from onions cut with a duller knife reached velocities of up to 40 m/s.

Therefore, to avoid tears when cutting onions, we need to use a sharper knife with slower cuts.

The team also tested chilled onions. Many people believe that chilling onions before cutting them can help reduce eye irritation. However, the team found that chilled onions seemed to release “significantly larger amounts” of droplets when cut.

The research was published on arXiv - an open access database that distributes scholarly articles in many fields.

ANH THU

Source: https://tuoitre.vn/nghien-cuu-moi-chi-cach-cat-hanh-khong-bi-cay-mat-20250521125137421.htm