Why Onions Make You Cry

Written by Studio AM.

You cut an onion, and your eyes begin to sting. Soon you are making tears, although you do not feel sad. The cut has started a chemical reaction.

An onion is made of tiny cells. Inside them, some chemicals are kept apart from enzymes, which help chemical changes happen. A knife damages the cells, allowing these materials to meet. A series of changes then produces a substance that can enter the air.

This substance reaches the surface of your eyes and irritates the nerves there. Your body responds by making more tears. The tears help wash away the irritant. The onion does not need to touch your face for this to happen: the substance travels through the air.

The important steps are damage, mixing, and irritation. A whole onion sitting nearby is different from one that has just been cut. Cutting opens the cells and starts the chain that can leave a cook with watery eyes.

Questions

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  1. Question 1 of 4

    What is the passage mainly about?

  2. Question 2 of 4

    According to the passage, what happens when a knife breaks the walls inside an onion?

  3. Question 3 of 4

    In this passage, a "reaction" is

  4. Question 4 of 4

    Why can a cut onion make your eyes water without touching your face?

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