difference between lime and lemon!

difference:

• A lime has denser flesh than a lemon which makes it heavier. Limes contain more acid than lemons, and are more sour (but lemons are small, green and more bitter before they mature and then turn yellow and more sweet when they mature. So what's the difference between a lime and an immature lemon?)
  

• When put into a glass or bowl of water, a lime will sink to the bottom, and a lemon will float on the top. Could the difference in density be due to a difference in sugar content or a difference in lipid (oil) content? Lipids are less dense than water. Lemons are known for their lemon oil. Cut a lemon and feel the oil on the surface. A small, dense, green, immature lemon floats in water!

source: http://wiki.answers.com/Q/What_is_the_difference_between_lime_and_lemon

source: http://images.google.com.sg/images?hl=en&source=hp&q=lemon+and+lime&gbv=2&aq=f&aqi=g3&aql=&oq=&gs_rfai=