How does the Olympic flame stay alight?
- 18 May 2012
How does the Olympic flame stays alight on the torch relay around Britain?
That's the burning question we've been asking here at Newsround.
The Olympic flame begins its mammoth tour round Britain on Friday 18 May 2012 and ends in London for the opening ceremony on 27 July.
But how will it stay alight for all those trips round the country, whizzing on zip-wires, braving whitewater rapids, and being taken up windy mountains?
How's the flame kept alight on planes?
It will be kept in a lantern, which has been allowed to go on a plane. It'll have two seats to itself, accompanied by a police officer who has been trained in firefighting.
What happens to the flame at night?
It will be kept in a lantern and be watched by security guards from a special protection team.
What's the fuel used to keep it burning?
It's gas - a mixture of two-thirds propane and one-third butane.
How is the flame passed from torch to torch?
One torchbearer will put their torch near that of the next torchbearer, and the fuel in each torch will allow the flame to pass from one to the other.
What happens if it gets blown out by the wind?
The flame has been tested to be weather proof. It works in temperatures between -5C to 40C, as well as in 95% humidity, rain, snow, and wind gusts of up to 50mph. It was even taken up Mount Snowdon, and the flame didn't go out.
What if it rains or there's a thunderstorm?
The torch can survive rain as long as it's not "bucketfuls" of water - rain simply evaporates off. If the torch was dropped into water off the side of a boat it would go out but the Torch Team have spares. If there was lightning, the relay might be stopped for safety reasons.
What happens if a torch is dropped?
Torches have been 'drop-tested' to a height of three metres to make sure they are safe.
OK - but what if the flame goes out, despite all this?
A 'mother flame' is always kept in a lantern along the Torch Relay. A spare torch is within 30 seconds' reach. It can then be re-lit from the mother flame which is 'descended' from the real Olympic flame in Athens, Greece.
How long does each torch stay alight?
Each torch should stay alight for 13 or 14 minutes but on average each torchbearer will run 300 metres which should take between three and six minutes.
How many torches are there and what happens to them after the relay?
There are 8,000 torchbearers, so that means 8,000 separate Olympic torches. Torchbearers are able to buy their torch to keep when their run has finished.