From Physics Research Archive - Page 4
The Doppler Effect and Sonic Booms - Dec 1, 2010
This image of the shockwave made by a speeding bullet is a shadowgraph--simply a photograph of the shadow of the bullet and the shockwave. Variations in the density of air refract the light used to make the shadow and produce bright and dark regions.
Quantum Cascade Lasers - Nov 1, 2010
The image above shows a quantum cascade laser captured by a camera that images infrared light. The laser light is the small dot in the middle of the round window. The laser itself--behind the window--is kept at a temperature of -193° C, just above the temperature of liquid nitrogen.
Do We Know What Killed the Dinosaurs? - Oct 16, 2010
In the image above (upper left) you can see two concentric circles. These mark the location of the Chicxulub crater, and the white line shows the coast of the Gulf of Mexico. See this Canadian site (scroll down to the third image) for a fuller explanation of how the image was made and for related images.
Image credit: Michael Kelzenberg; image source; no larger image available
In a radical departure from the traditional design, a Caltech group has produced a flexible solar cell using an array of silicon wires. By packing light-scattering particles in among the wires, the researchers have achieved efficiencies up to 85%, despite the fact that the silicon wires take up only 2% of the volume, with significant cost reduction expected in a commercial version. To learn more, see this Caltech press release and this Scientific American article.
The Physics Classroom: Total Internal Reflection - Sep 16, 2010
The optical fiber in the photo above doesn't just guide the beam--the fiber produces the beam. Instead of a tube of helium and neon gas, or a piece of ruby, the "active medium" of this laser is added to the glass in the fiber. Since the mirrors are just the polished ends of the fiber, there is nothing to go out of alignment, and maintenance is easy.
Network Theory: A Key to Unraveling How Nature Works - Sep 1, 2010
You are looking at a network diagram that shows the interconnectedness of the world economy. To learn more about this network, visit Mapping the World Economy.
Making a supersonic jet in your kitchen - Aug 16, 2010
What exactly happens when an object makes a splash in water? The disk shown above was pulled into water in a reproducible way to investigate the splash.
The Real Sea Monsters: On the Hunt for Rogue Waves - Aug 1, 2010
This "rogue wave" broke over the deck of an oil tanker, and was much taller than the other waves on the ocean at the time. See Freak Waves, Rogue Waves for graphs of rogue waves building up in the ocean, and for the measurement of one that struck an oil platform in the North Sea.
From Soap Bubbles to Technology - Jul 16, 2010
The soap film you see here, made in between two metal rings, is called a catenoid, and it uses the minimum area to enclose a given volume. Click on the image to see another example of a "minimal surface" soap film.
About Dust - Jul 1, 2010
This satellite image shows a recent dust storm in China that was so large it spread out to neighboring countries. For more on this storm, see About Dust.