WHY ONIONS MAKE US CRY

CONNECTIONS TO CHEMSITRY

Why do onions make you cry?

What does onions making us cry, have to do with chemisty?

TIP

Erin Matz Tuesday, November 3rd, 2009

2

3(g)

2 4(aq)

SO + H O(1)---> H SO

EQUATION

http://www.coolquiz.com/trivia/explain/docs/onion.asp http://books.google.com/books?id=LupAi35QjhoC&pg=PA239&lpg=PA239&dq=Equation+for+why+do+onions+make+us+cry%3F&source=bl&ots=INhIANL65d&sig=X8dMxriNNrZVbFjQWaIdz2TfGeQ&hl=en&ei=NtfwSse8HNHglAeEl-nqCA&sa=X&oi=book_result&ct=result&resnum=5&ved=0CBYQ6AEwBA#v=onepage&q=&f=false

CITED RESOURCES

It's not actually the strong smell that makes us cry, it's the gas that is released from the onion when we cut into it.

The onion contains oil that has sulphur trioxide, SO3(g) in it. The sulphur makes our noses and eyes irritated. When you cut into the onion, a gas called Propanethiol S-oxide, mixes with the enzymes in the onion and releases a passive sulphur compound. When the passive sulphur compound meets with the water produced by tear ducts in our eye lids, it then produces sulphuric acid. In response to the acid, we blink, producing tears which flushes out the sulphuric acid.

Because our hands are filled with the sulfur and oils from cutting the onion, it makes the situation worse by rubbing your eyes!