To prevent crying while chopping an onion, you can try the following tips:
Chill the onion: Before cutting the onion, place it in the refrigerator for about 30 minutes. The cold temperature can slow down the release of the compounds that cause tears.
Use a sharp knife: A sharp knife will create cleaner cuts and cause less damage to the onion cells, releasing fewer irritants.
Cut near a running water source: Cutting the onion under running water or near a steady stream of water can help wash away the irritants, reducing their concentration in the air.
Ventilation: Make sure the area where you're chopping the onion is well-ventilated. Turn on a fan or open a window to help disperse the onion's volatile compounds.
Avoid cutting the root end first: The root end of the onion has a higher concentration of irritants. Start by cutting off the stem end (opposite the root), as it releases fewer irritants.
Use goggles or glasses: Wearing goggles or glasses can create a barrier between your eyes and the onion's irritants.
Cutting under running water: Some people find that cutting the onion under running water or while submerged in water helps reduce the irritants in the air.
Freeze the onion: Some suggest freezing the onion for about 15 minutes before chopping. This can also slow down the release of irritants.
Cut with the grain: Cut the onion with the grain (from root to stem) rather than against it. This can help minimize the release of irritants.
Remember that everyone's sensitivity to onion fumes varies, so you might need to try a few of these methods to find what works best for you.