Sink or Float With Lemons and Limes

It’s time for a fun little science lesson.  Will lemon and lime slices sink or float?  In fact, this is something that has perplexed scientists for some time now.  It was when this hit the BBC news over the summer that I thought if it is something of concern to the wider science community, it was definitely something that we should explore as well.

The supplies are easy enough to source for this sink or float experiment:

• Lemon
• Lime
• A sharp knife
• A bowl of water

Our hypothesis:   We thought we would stick with the thoughts of those higher up in the science field than us and proposed that the lime would sink and the lemon would float.

Our Method:  We cut equal-sized slices from a lime and from a lemon as seen here and Tristan placed them into a bowl of tap water (we used the water from the cold tap).

Our Observations:  After the slices were gently placed in the bowl of water Tristan could clearly see that the lemon did indeed float, and the lime sank to the bottom of the bowl.

Our Results:  We concluded that the scientists are correct and that lime slices sink and lemon slices float!

Our Discussion:  Although this worked for us, would a change in the water temperature, the size of the slices, or the type of bowl make a difference?

Why do lemons float and limes sink?  When we did this experiment Tristan was too young to understand density, but if you’d like to learn more about the possible reasons why, Steve Spangler has some deeper explanations on his website.

Why not try this out for yourself at home?  And don’t forget to do some baking with the left-over fruit, that could be a whole other science experiment!

Do you like kitchen science?  We’ve also measured carrot tops for re-growth and made a solar oven.  Click over to our science activities page for more ideas.