Thunderstorm Research Shocks Conventional Theories; Florida Tech Physicist Throws Open Debate On Lightning's Cause

ScienceDaily (Nov. 6, 2003)

In the latest issue of Geophysical Research Letters, the National Science Foundation CAREER Award winner caps two years of lightning research with a startling conclusion: The conditions inside thunderstorms that were long thought necessary to produce lightning actually do not exist in nature.

"For generations, we've believed that in order to produce a lightning discharge, the electric fields inside storms must be very big, similar to the fields that cause you to be shocked when you touch a metal doorknob," said Dwyer.

The problem is scientists have searched inside thunderstorms for many years, looking for these large electric fields, only to come up empty handed. Some researchers have suggested that maybe we haven't been looking hard enough; maybe the big electric fields are really there, but they were somehow just missed. Now, Dwyer's new theory shows that these searches were actually in vain; super-sized fields simply don't exist.

"What we've discovered is a new limit in nature. Just as a bucket can only hold so much water, the atmosphere can only hold a certain sized electric field. Beyond that, the electric field is stunted by the rapid creation of gamma-rays and a form of anti-matter called positrons," he said.

While Dwyer's research shows that lightning is not produced by large, unseen electric fields inside storms, the triggering mechanism remains a mystery.

"Although everyone is familiar with lightning, we still don't know much about how it really works," said Dwyer.

Text 3

Practice 1. Choose the key sentence in each paragraph.

Practice 2. Re-read the text to find out the author’s main idea:

1. The electric charge between oil and water is not caused by the inevitable "impurities" present in oils, but rather by certain intrinsic properties of the water molecules involved

2. Water repelling molecules are said to be hydrophobic .

3 The hydration is important for many biological processes: protein folding, membrane formation, transport of proteins across an interface, the transmission of action potentials across membranes.

4 Hydrophobic interfaces although long studied, are poorly understood.

Practice 3. Make a review of the text.

Illuminating the No-Man's Land of Waters' Surface: Strong Electric Charge Observed at the Interface Between Oil and Water Is Not Due to Impurities

ScienceDaily (Nov. 27, 2012)

Here's an amusing kitchen-table experiment to illustrate waters unusual properties: put a drop of pure insulating oil in a glass of pure, non-conducting water, and create an electric field using two wires hooked up to a battery. You'll see the oil move from the negative to the positive pole of the little circuit you've created. You have created charge in a mixture that was neutral, and a huge amount of it too, judging from the speed at which the droplets move. The same thing happens for gas bubbles in water; the phenomenon of charging applies to all hydrophobic/water interfaces.

A century of debates

It's not a new discovery; scientists have observed the phenomenon in the middle of the 19th century. But despite more than a century of research, the reason why such a huge electric charge exists is still the subject of heated debate.

In an article published this week in Angewandte Chemie -- a journal of reference in the field -- EPFL scientist Sylvie Roke challenges a hypothesis put forward last spring in the same journal. With experimental proof to back her up, the holder of the Julia Jacobi chair in photomedicine makes her case: the phenomenon is not caused by the inevitable "impurities" present in oils, as her colleagues claim, but rather by certain intrinsic properties of the water molecules involved.

Show the unseeable

For proof, Roke turns to the technologies in which she is an expert -- nonlinear optics and light diffusion. Using carefully filtered lasers channeled through a complex circuit of mirrors and lenses, she "hits" her sample -- barely a drop -- and measures the wavelength of the light that escapes from it. With this she can detect whether or not there are nanoscopic molecules on the interface between the oil and the water.

The precision of the observations "shows that negative charges exist even in a total absence of surface impurities, and thus the explanation put forward by my colleagues, which was derived from charge measurements and chemical titrations of the bulk liquids, doesn't hold up," says Roke. "We have developed a unique apparatus that can distinctly measure the interfacial structure of a layer on the sub-nanometer length scale that surrounds a droplet of oil in water. Thus, we can 'see' what is on the interface, and do not have to deduce it from comparing bulk properties, which is far less accurate."

Disproving a hypothesis isn't enough to explain a phenomenon, however. Roke is studying a promising avenue, that explores the intrinsic quantum nature of the water molecule itself, which might be responsible for the phenomenon. "The measurements we've made as part of this refutation could be used to try and prove this explanation," she says. "It's fascinating, because quantum effects (the smallest of the smallest) might be responsible for macroscopic charging effects that influence so many properties that relate to the functioning of the human body."

Text 4

Practice 1. Choose the key sentence in each paragraph.

Practice 2. Re-read the text to find out the author’s main idea:

1. The three most common types of sircuits are ring, radial and lighting circuits.

2. Several types of electrical circuits can be wired in your home.

3. If you're considering wiring an electrical circuit it's important to understand each type so you can choose the correct one to safely power your electrical items.

4. Each type of circuit has a different purpose and is wired to carry certain amperes.

Practice 3. Make a review of the text.