切洋葱秒变“泪人”，是不是你的日常写照？我们熟知的生化反应只是其一，科学家又解锁了全新物理视角。刀具快慢、洋葱温度都会影响辣眼程度，老偏方也被证实并不管用。掌握正确切法，从此和流泪说再见。
Onions.
We love to hate them.
Or rather, our eyes hate that we love them so much.
They're one of the oldest recorded vegetables in continuous use, with records dating back 4,000 years, and they've made their way into pretty much every culinary tradition in the world.
As amazing as they are, they've got one really annoying flaw.
All of the crying.
Every time you cut into one, you can't help but well up like you're watching a sad dog movie.
We actually know quite a lot about what's happening at the chemical and biological levels to make this reaction happen.
But a study published in October of 2025 looks at the onion-crying problem from a new perspective—physics.
They examined the droplets flung out of an onion being cut in various ways with a precisely-tuned onion guillotine.
