The Colour of Electrons and the CCD

Written by Charles Douglas Wehner

The world of physics is a strange world indeed.

Atrepparttar end ofrepparttar 127661 nineteenth century it was found that a negatively charged metal plate would discharge when illuminated, but a positively charged one would not.

Then it was found by some researchers that NO metal plate would discharge.

Other researchers found that red light had no effect, but blue dischargedrepparttar 127662 plate.

The "photoelectric effect" was a mess.

Max Planck discovered that light consisted of particles. And each particle (or quantum) had an energy that could be defined as Joules.

The science was very simple. Takerepparttar 127663 frequency of that light particle, multiply by Planck's constant, and you find how many Joules of energy are in that particle.

You could even pretend that this light particle collided with an electric particle -repparttar 127664 electron. If so, it would transfer its energy to that electron in justrepparttar 127665 same way asrepparttar 127666 chemistry of a battery energises electrons.

So we could definerepparttar 127667 near infra-red as 1.7 electron volts, and atrepparttar 127668 other end ofrepparttar 127669 spectrum ultra-violet begins at 3.2.

For this he gotrepparttar 127670 Nobel prize.

Withrepparttar 127671 electron-voltages of light being now defined, Einstein decided to tacklerepparttar 127672 problem ofrepparttar 127673 metal plate. Why was it that only NEGATIVE electricity would be discharged? Because there is only one kind of "charge-carrier". Or so it seemed atrepparttar 127674 time.

Why did some researchers find that NO metal plate would discharge? Becauserepparttar 127675 voltages are LOW. Evenrepparttar 127676 slightest film of grease or dirt could INSULATE against less than 3.2 volts.

And why did blue light work when red did not? The answer lay in Planck's electron voltages.

Einstein discovered thatrepparttar 127677 effect varied withrepparttar 127678 TYPE of metal used for that plate. Each element, sodium, potassium, iron, copper,repparttar 127679 noble metals such as platinum &c., had a unique voltage.

That voltage representedrepparttar 127680 energy that had to be present inrepparttar 127681 light in order to freerepparttar 127682 electrons.

That voltage became known asrepparttar 127683 WORK FUNCTION.

Knowing this, scientists began to researchrepparttar 127684 forces that hold atoms together. Inrepparttar 127685 technical literature, Einstein's name was cited so often thatrepparttar 127686 Nobel Prize Committee could not ignore it.

So Einstein wonrepparttar 127687 Nobel Prize.

It is true that further researches modifiedrepparttar 127688 simple model that scientists had used. For example,repparttar 127689 particle model of Planck suggested that an ultra-violet "PHOTON" could travel for thousands of millions of years through space, retaining its 3.2 eV energy - and NEVER become two photons at 1.6 eV each.

This isrepparttar 127690 LAW OF CONSERVATION OF MATTER.

But after that huge journey, it needs only for that photon to hit a suitable crystal and it does indeed divide. You get TWO photons forrepparttar 127691 price of ONE. This is only possible ifrepparttar 127692 photon consists of NOTHING.

Sorepparttar 127693 wave model of light began to supervene. Waves consist of nothing but a pattern. And questions were asked as to whether there is a SUBSTANCE in whichrepparttar 127694 waves are formed. Does space consist of aether?

Our Bodies, Our Fears

Written by Ransy Reynis

Our Bodies, Our Fears

I think this is worth reading it.

As they reach forrepparttar duct tape, Americans say they’re more anxious than ever. Scientific research about how our brains and bodies process fear can teach us how to live with long-term stress

By Geoffrey Cowley NEWSWEEK

Feb. 24 issue — Anthony Lepre started feeling awful almost as soon as Tom Ridge putrepparttar 127660 nation on high alert for a terrorist attack last week. The normally well-adjusted Los Angeles chiropractor started tossing and turning instead of drifting off to sleep at night. He awoke inrepparttar 127661 middle ofrepparttar 127662 night short of breath, his heart pounding. Andrepparttar 127663 sound of his telephone seemed a sure sign of bad news.

BY MIDWEEK, HE was rushing off to Costco to stock up on fruit juice, bottled water, peanut butter, canned tuna “and extra food for my cats Monster, Monkey and Spike.” He also picked up a first-aid kit, six rolls of duct tape and a bulk package of plastic wrap to seal his windows. “The biggest problem was that I felt helpless,” he says, “completely powerless overrepparttar 127664 situation.” The health-conscious 46-year-old even found himself chomping pizza and sweets, figuring a few treats would help him “forget aboutrepparttar 127665 situation for a while.”

And so it went for millions of Americans. The recent barrage of bad news—nukes in North Korea, snipers in Maryland, a failing economy, an imminent war, a threat of domestic terror—has left this privileged nation feeling unusually vulnerable and uncharacteristically anxious. Gas masks and biohazard suits are selling as briskly as duct tape and plastic sheeting. Winter vacations are on hold. Psychotherapists are working overtime. And even people who soldiered on after 9-11 are now blinking. Thirty-five-year-old Kateria Niambi, a lifelong Brooklynite who works as a marketing director in lower Manhattan, never thought of leaving New York duringrepparttar 127666 grim fall of 2001. Yet she recently bought a house in suburban New Jersey and now plans to pack up her two daughters and move. “It was like, ‘Where can I go that my kids will be safe?’ ” she says.

Cont'd on page 2 ==> © 2005
Terms of Use