"There's something here alright, but exactly what is it?"
Non-combusted oxygen. Some of the o2 burns with the gas; the extra o2 burns the metal and is ignited by the existing flame.
It's an old trick. Didn't you make a smoldering toothpick explode in 7th grade chemistry by adding 02?
Non-combusted oxygen. Some of the o2 burns with the gas; the extra o2 burns the metal and is ignited by the existing flame. It's an old trick. Didn't you make a smoldering toothpick explode in 7th grade chemistry by adding 02?
Additionally, your hand (being mostly water) has a specific heat of close to 4.184 J/gK, while tungsten has a specific heat of 0.13 J/gK. This means that when the flame is placed on a piece of tunsten, it will heat up 32.2 times faster than the same-sized portion of skin would.
But wait, there's more! Also note that "timer" mentioned that it was a tungsten *wire*. This has a very small volume, and as a result it will heat up far faster than a larger chunk of tungsten would, much less a large chunk of your hand. The reason, in short, is that the energy of the flame has more volume to spread through in the larger sample, and the temperature change is thus smaller, whereas in the thin wire it has nowhere else to "go" but in the one spot being torched. If your finger is ten times the diameter of the wire, for example (and it's probably a lot larger), it has 10x10 = 100 times as much volume as the wire, and compounded with the 32.2 difference in specific heat of flesh versus tungsten, this means that the tunsten wire will heat up 3220 times faster than the finger when the torch is applied to it. And that's just a finger -- these demonstrations are usually done against a larger portion of the hand than just a single finger.
So it's little wonder that the wire quickly reaches the melting point while the hand doesn't suffer any immediate damage.
Add to that fact that in these demonstrations the flame isn't just focused on the hand in one spot for any length of time -- as you can see in the CNN video linked above, it's *waved* over a large swatc of hand, and not allowed to spend any length of time in one spot (unlike the "metal welding" demonstration). You can do the same trick with a candle flame -- keep your hand moving steadily over it, and you won't get burned.
Finally, there's the oxidation factor that MeanWestTexan points out. Tungsten readily oxidizes, and needs to be protected from oxygen, especially at high temperatures. As the webelements.com entry for Tungsten points out, "The metal oxidises in air and must be protected at elevated temperatures." Once the "welding" flame hits it and elevates its temperature, it'll rapidly combine with any excess oxygen and literally burn up. The same is not true of your hand -- skin is specifically configured *not* to be harmed by exposure to oxygen, for obvious reasons.
Finally, a mixture of H2 and O2, which is most likely what's being used in that demo, burns a cooler than, say, an acetylene torch or an arc welder, *and* has much lower heat density, both of which will yet again reduce the risk of the "waving it over my hand" trick, while still providing enough energy (and free oxygen) to toast the tungsten wire.
So all in all, there's nothing mysterious about being able to wave a flame over your hand without damage and yet being able to use the same flame to crisp a tunsten wire.
Sometimes, watching these reporters be impressed by ordinary chemistry and physics, I am reminded of the way that explorers used to awe primitive tribes by showing them Bic lighters in operation. "Heap big magic!"
Yes, well, in that same Dennis Lee science show he demonstrated the Pantone catalyic chamber that removed all CO2, other pollutants from a simple otto cycle engine. It has a blue glow inside and only pure O2 comes out. Strange story there. Appearently it's real enough but this Pantone guy is a complete dufuss. A lot of investors put a LOT of money into developing this concept. He promptly turned around and spent all their money on fancy cars, houses, etc; and didn't lift a finger to develop/market it. They threw him in jail. This was last autumn, haven't heard anything since...