Unfortunately, you don't get anything for free in this universe. American inventor John Kanzius claims he has developed a way to burn water to make energy, but the process takes more energy than it creates - in accordance with the law of thermodynamics.
Basically, Kanzius shows that if you put a test-tube full of salt water in a powerful radio-frequency electromagnetic field (in a slightly loose sense, radio waves) then you see what looks like a flame coming off the top.
The phenomenon is actually pretty well understood in physics: The electromagnetic field is ripping the water molecules apart into hydrogen and oxygen atoms. The electromagnetic field also rips electrons from the hydrogen and oxygen atoms, ionizing them, and when the electrons rejoin the atoms that lost them, light is released. You see this phenomenon any time you look at a spark. To see that you could get a spark just from radio waves, think of what happens when you put a fork into a microwave oven. (This isn't a good idea, as you can wreck the oven or start a fire.)
If sodium ions are present from the salt, you get a bright yellow color that adds to the flamelike appearance. You can see that same color in a yellow street light (which works by making a spark in sodium vapor). You can also toss table salt into a stove flame and get the same effect, with the pale blue flame becoming bright yellow.
So, Kanzius's "flame" is a combination of the burning of hydrogen and oxygen from water and the light emitted by the gases being heated by energy from the radio waves, with some extra yellow from the sodium of the salt. You get energy out, but no more than you put in. It looks like water is burning, but turn off the power and there's no more flame, just as when you turn off the power to a light bulb there's no more light.
Dr. Knowledge is written by physicists Stephen Reucroft and John Swain, both of Northeastern University. E-mail questions to drknowledge@globe.com or write Dr. Knowledge, c/o The Boston Globe, PO Box 55819, Boston, MA 02205-5819.
