What you Need
What to do
If you bend a piece of orange peel you often get a spray of orange oily stuff coming out. The idea is to direct this spray upwards into the side of a candle flame.
Be careful, this can be more effective than you expect. Make sure that your hands and anything else easily damaged by flame is below the candle flame!
What may happen
You should be able to produce an impressive fireball as the spray hits the flame.
Why does it happen?
Oranges have a peel which includes little compartments full of oily substances. When you bend the peel the outer layer of skin is stretched, and these compartments are flattened. This squashes them until they eventually fail squirting out their contents in the form of a spray.
The oils which spray out are hydrocarbons - a bit like petrol - and are highly flammable, and you have sprayed them out of the orange, so they are very well mixed with air. This means that the oxygen from the air can get to the oil in many places at the same time, so it burns very quickly in a fireball.
Why do oranges have such flammable skins?
Oranges are a fruit, they are designed to get a large animal to eat them, then move somewhere else and to deficate the undigested seeds in a nice blob of fertiliser somewhere distant from the parent plant where it won't be competing for resources. So an orange tree wants its fruit to be eaten by large animals, but not by insects and fungi.
The oily skin is waterproof, so it is difficult for fungi to get a hold, and the oils are both poisonous and repellant to insects - this is why citronella is such a good mosquito repellent. It just so happens they are also very flammable.
This is great experiment. Personally I thought it deserved to win the BIG event demo competition. sat074, Thu, 30th Jul 2009
Glad you liked it, I think I need to work on not being petrified when doing demos in front of BIG... Ho humm. I have lots of other things to do next year. daveshorts, Thu, 30th Jul 2009
Nice resrarch.I perticularly never have thought to do this type of thing. dvijay, Wed, 12th Aug 2009
This is so neat! Great work! cindy, Wed, 26th Aug 2009
Randy Heisch, from Georgetown in Texas, sent us these amazing pictures of his own Fruit Fireballs:
who knew orange was a colour fruit and could be so much fun!! :-) LoL! chloe wyld, Wed, 23rd Sep 2009
this is very interesting! thanks xzel, Thu, 5th Nov 2009
I used this once in a dragon show,and made the orange and fire d dragon's breth. mama1, Fri, 5th Feb 2010
The video is really cool! We plan to try it at school! AWESOME V.i.V, Thu, 21st Oct 2010
this looks awesome demot, Thu, 31st Mar 2011
what you may not know about the Oranges skin is the fact that if you peel it and leave it to dry very hard to the point of been crisp it almost BURSTS into a mini fireball of doom.! No am not pulling your leg, my grandad told me this odd little trick about starting log or coal fires in WW2, its a very good firestarter for subborn fires which will not light up. Note if you try this at home be careful as it will suddenly burn up without warning once a flames touch comes into contact. If you wish to try it you must air dry the skin until its super rock hard. matt, Sat, 23rd Jul 2011
This is really interesting experiment! I would use it for my science project:) BM, Sun, 3rd Jun 2012
Excellent Experiment. Tried this today at home. Here is the high speed (1000 fps and 480 fps) video shoot. http://youtu.be/HwYEICxb4BU Kapil, Fri, 19th Oct 2012