Believe it or not, Harvard chemists can snuff flames with electricity

Since the time humans first began to control fire around 400,000 years ago we have had just a few simple tools to douse the flames.

Now some Harvard University chemists believe they have found a way to bring fire suppression into the digital age by controlling flames with electricity.

During a series of experiments to study the chemical nature of fire, scientists were surprised to learn that by applying an electrical field to a burning flame it easily went out. All they needed to do is wave a wand-like, electrified metal wire near the flame.

‘What did I do wrong?’

“As a scientist you find it fascinating, but you have to control your emotions and ask how nature is trying to deceive you,” Ludovico Cademartiri recalled about the experiment. “I was thinking, ‘What is wrong with this experiment? What did I do wrong'”

As it turns out, he and other chemists in the lab of Harvard chemist George Whitesides had done nothing wrong.

Nearly all previous study of flames and electric fields involved those generated by direct current, or DC, instead of alternating current.

“What we discovered is that by applying an oscillation field, AC voltage, the effects are completely different,” Cademartiri said. He reported the findings Sunday at the national meeting of the American Chemical Society.

In their experiments the researchers used a 600-watt power source — about the same as a modest home-theater stereo — to create an electric field near flames as large as 18 inches tall.

They found the field created an organized “flow” of charged particles inside the flame, and that the flame was literally pushed away from the burner and put out.

It’s too early to say how well the effect will scale to larger flames. Cademartiri said he and his colleagues have begun collaborating with the U.S. Naval Research Laboratory in Washington, D.C., which has facilities devoted to the study of fire.

“I’m very optimistic that something very relevant is going to come out of this new capability,” he said.

More efficient energy?

The most obvious effect is fire suppression. But there are other applications as well. The world still derives about 90 percent of its energy from burning coal, natural gas and other products.

The potential to better control the internal flow of combustion could lead to more efficient energy production, among other benefits.

“Our hypothesis was that if we could find any new way to control flames in a novel way, we have a real chance to make a real big impact,” Cademartiri said. “This is our hope.”