Category Archives: Physics

Really, Nature?

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Quantum mechanics flummoxes physicists again

If you ever want to get your head around the riddle that is quantum mechanics, look no further than the double-slit experiment. This shows, with perfect simplicity, how just watching a wave or a particle can change its behaviour. The idea is so unpalatable to physicists that they have spent decades trying to find new ways to test it. The latest such attempt, by physicists in Europe and Canada, used a three-slit version — but quantum mechanics won out again.

Flummoxed? Unpalatable?

It looks like a neat experiment. Maybe I’m missing something, but I don’t understand how the experimenters were flummoxed (the results agree with QM), nor do I see what they were getting at with the mention of relativity. And I don’t think I’ve found which-path behavior to be unpalatable, but then, I always used chocolate-covered gratings.

Celebrating the Enabler of Cheap Laser Cooling and Trapping

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Landmarks: Invention of the CD-Player Laser

The invention of the semiconductor laser took lasers from the scientist’s lab and action hero’s arsenal to every living room DVD player and grocery store scanner. It began with the serendipitous discovery in 1962 that gallium arsenide could be made to produce surprisingly intense light. Later that year, the first gallium arsenide laser was reported in Physical Review Letters. The modern descendants of that device are the tiny lasers that abound in countless modern appliances.

… and atomic physics labs throughout the world.

Aaaayyyy! Fonzie Weighs in on Global Warming

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Installing cool roofs.

Global Model Confirms: Cool Roofs Can Offset Carbon Dioxide Emissions and Mitigate Global Warming

Because white roofs reflect far more of the sun’s heat than black ones, buildings with white roofs will stay cooler. If the building is air conditioned, less air conditioning will be required, thus saving energy. Even if there is no air conditioning, the heat absorbed by a black roof both heats the space below, making the space less comfortable, and is also carried into the city air by wind—raising the ambient temperature in what is known as the urban heat island effect. Additionally, there’s a third, less familiar way in which a black roof heats the world: it radiates energy directly into the atmosphere, which is then absorbed by the nearest clouds and ends up trapped by the greenhouse effect, contributing to global warming.

How Insects Have Solved the Baggage-Fee Problem

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NPR: Look Up! The Billion-Bug Highway You Can’t See

You can see them launching themselves, says entomologist Matt Greenstone:

“They just stand straight up on their little back legs and just by doing that they can get part of their body up into this layer [of air] where it’s more turbulent and then, if you can get a ride on a parcel that’s going up, you can get off the ground and then if you’re lucky you can get carried aloft.”

Living Dangerously, Optional

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The year.

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A year on earth is measured by one complete trip around the sun. Seems simple enough but there is a problem. The earth doesnt travel in a path around the sun that returns it to its starting point. So how do we know when the year starts or ends?