 It's a wet and windy evening outside at Bristol at the moment, but not to worry, because it's about to get a lot hotter. Just behind me, you might be able to see a burning fire. Now myself and over 80 other people are going to be raising some money for St Peter's hospice, which is a Bristol-based charity which helps the care for adults with life-limiting illnesses. Now me and everyone else, we're going to be walking across that. Their foot. So how is this actually possible? Thermal conductivity refers to an object's ability to transfer heat to another object. Here I have a piece of metal which I'm going to heat up with this blowtorch until it gets to about 400 degrees and that's going to be about the same temperature which the coals will be outside later on. Using our infrared camera we can see the piece of steel is now over 350 degrees, but if we switch back to visible light and dim the lights, we can see that it's now glowing red hot. This happens to the coals as well and this incandescent red light is actually emitted by the atoms of the metal and coals as they rapidly vibrate at these very high temperatures. The walk itself is made of coals and wood, which in turn are made mostly of carbon. Now thankfully the walk isn't made of steel because this metal is a far better conductor of heat than the carbon. You've probably encountered thermal conductivity in your kitchen at home. Imagine having baked some muffins. Now you can briefly place your bare hands inside the oven without them getting burned because the air inside, despite being hundreds of degrees, is a very poor conductor of heat. But if you try to pick up the metal baking tray, that's a bad idea. So because carbon is such a poor thermal conductor and I'm going to be walking pretty quickly, those red hot coals aren't going to have enough time to transfer the heat to my feet in theory. I think it's time we went back outside. So here we are outside at Bristol. The coals are just over there. They're 400 degrees Celsius and I'm going to be walking on them with bare feet but I'm willing to put my feet where the physics is and put this to the test. Let's give it a go. I've got to say that is one of the most amazing things I've ever done. There was a moment just before I was about to walk when I was actually feeling pretty nervous and I was thinking can I actually do this and is the science behind this actually going to prevent my feet from burning but I'm here and I'm still in one piece with no burns at all. So that is the science of fire walking. For more Flamethrower science why not watch how to set fire to ice and how to make a rocket and for more science every week click subscribe. Thanks for watching.