{"id":8761,"date":"2021-03-08T06:33:43","date_gmt":"2021-03-07T19:33:43","guid":{"rendered":"https:\/\/scienceillustrated.com.au\/blog\/?p=8761"},"modified":"2021-03-08T06:34:57","modified_gmt":"2021-03-07T19:34:57","slug":"why-do-our-eyes-water-when-we-chop-up-onions","status":"publish","type":"post","link":"https:\/\/scienceillustrated.com.au\/blog\/ask-us\/why-do-our-eyes-water-when-we-chop-up-onions\/","title":{"rendered":"Why do our eyes water when we chop up onions?"},"content":{"rendered":"<p><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter size-full wp-image-8762\" src=\"https:\/\/scienceillustrated.com.au\/blog\/wp-content\/uploads\/2021\/03\/onion.jpg\" alt=\"shutterstock\" width=\"1872\" height=\"1444\" srcset=\"https:\/\/scienceillustrated.com.au\/blog\/wp-content\/uploads\/2021\/03\/onion.jpg 1872w, https:\/\/scienceillustrated.com.au\/blog\/wp-content\/uploads\/2021\/03\/onion-300x231.jpg 300w, https:\/\/scienceillustrated.com.au\/blog\/wp-content\/uploads\/2021\/03\/onion-1024x790.jpg 1024w, https:\/\/scienceillustrated.com.au\/blog\/wp-content\/uploads\/2021\/03\/onion-768x592.jpg 768w, https:\/\/scienceillustrated.com.au\/blog\/wp-content\/uploads\/2021\/03\/onion-1536x1185.jpg 1536w\" sizes=\"(max-width: 1872px) 100vw, 1872px\" \/><\/p>\n<p class=\"p1\">Onions emit a sulphur-containing gas when they are chopped. The gas irritates the cells of the eye, which react by producing tears that are intended to clear away the substance.<\/p>\n<p class=\"p1\">In ordinary onions, the gas originates because the enzyme alliinase is liberated to react with a sulphur-containing amino acid, producing a sulphonic acid. Another enzyme subsequently converts the sulphonic acid into lachrymatory PTSO (propanethial-S-oxide).<\/p>\n<p class=\"p2\">Onions have evolved the ability to secrete PTSO as a survival mechanism. Onion bulbs grow underground, where they would be easy prey for small burrowing animals if they lacked<span class=\"Apple-converted-space\">\u00a0 <\/span>any self-defence strategies.<\/p>\n<p class=\"p1\"><span class=\"s1\"><b>Three ways to avoid onion tears<\/b><\/span><\/p>\n<p class=\"p2\"><span class=\"s1\"><b>1. <\/b>Use a tight diving mask or swimming goggles.<\/span><\/p>\n<p class=\"p2\"><span class=\"s1\"><b>2. <\/b>Peel the onions. Place them in the freezer for 30 minutes, and then chop them.<\/span><\/p>\n<p class=\"p2\"><span class=\"s1\"><b>3. <\/b>Hold a slice of bread in front of your face with your teeth (it will absorb the gas).<\/span><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Onions emit a sulphur-containing gas when they are chopped. The gas irritates the cells of the eye, which react by producing tears that are intended to clear away the substance. In ordinary onions,&#8230;<\/p>\n","protected":false},"author":15,"featured_media":8762,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[52,98],"tags":[928,139,927,926,925],"class_list":["post-8761","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-ask-us","category-biology","tag-alliinase","tag-biology-2","tag-chopping","tag-cry","tag-onion"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/scienceillustrated.com.au\/blog\/wp-json\/wp\/v2\/posts\/8761"}],"collection":[{"href":"https:\/\/scienceillustrated.com.au\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/scienceillustrated.com.au\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/scienceillustrated.com.au\/blog\/wp-json\/wp\/v2\/users\/15"}],"replies":[{"embeddable":true,"href":"https:\/\/scienceillustrated.com.au\/blog\/wp-json\/wp\/v2\/comments?post=8761"}],"version-history":[{"count":1,"href":"https:\/\/scienceillustrated.com.au\/blog\/wp-json\/wp\/v2\/posts\/8761\/revisions"}],"predecessor-version":[{"id":8763,"href":"https:\/\/scienceillustrated.com.au\/blog\/wp-json\/wp\/v2\/posts\/8761\/revisions\/8763"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/scienceillustrated.com.au\/blog\/wp-json\/wp\/v2\/media\/8762"}],"wp:attachment":[{"href":"https:\/\/scienceillustrated.com.au\/blog\/wp-json\/wp\/v2\/media?parent=8761"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/scienceillustrated.com.au\/blog\/wp-json\/wp\/v2\/categories?post=8761"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/scienceillustrated.com.au\/blog\/wp-json\/wp\/v2\/tags?post=8761"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}