Why do onions make you cry?
http://chemistry.about.com/od/chemistryfaqs/f/onionscry.htm
How to chop an onion
http://culinaryarts.about.com/od/knifeskills/ss/onionchop.htm
How to power an ipod with an onion
http://www.youtube.com/watch?v=GfPJeDssBOM
http://science.howstuffworks.com/onion-power-ipod.htm