From Physics Research Archive - Page 2
The Invention of the Electric Guitar - Jun 1, 2012
The photo shows a modern electric guitar prototype developed in 1940 by a physicist at North Carolina State University. Check out this NCSU webpage to learn more.
Newton's 3rd Law - May 1, 2012
What is the purpose of the small rotor on the back of this helicopter? In fact, it's needed because of Newton's third law--for every action force there is an equal and opposite reaction. The helicopter puts a force on the main rotor shaft to make it turn, and the rotor shaft puts an equal and opposite force back on the helicopter.
X-rays from free electrons - Apr 1, 2012
The spiral track above was made by an electron moving in a magnetic field. Since motion along a curved path requires a force perpendicular to the direction of motion, the electron is accelerated. Accelerated charges radiate electromagnetic waves, so the electron loses energy and spirals inward. To learn more about this process, see X-rays from free electrons.
image credit: A. Mugarza, C. Krull, S. Stepanow, G. Ceballos, and P. Gambardella, CIN2; image source; larger image
Electronic Handedness in Copper-Silver Combo - Mar 1, 2012
Notice how the two images above have opposite handedness? These images show electronic properties of a small layer of copper on top of silver, but neither silver nor copper have any handedness themselves. To learn more, visit this American Physical Society webpage.
image credit: D. Lafreniere, R. Jayawardhana, M. van Kerkwijk (University of Toronto); image source; larger image
APOD: Companion of a Young, Sun-like Star Confirmed - Feb 1, 2012
You are looking at the first telescopic image of a confirmed planet in orbit around a Sun-like star. The young planet is still quite warm, and therefore radiating considerable energy, which makes it relatively easy to detect. To learn more, see APOD: Companion of a Young, Sun-like Star Confirmed.
Wing Vortices - Jan 1, 2012
This image from ONERA, the French aerospace lab, shows a simulation of the wake of an aircraft, looking along the direction the aircraft is moving. To learn more, visit Wing Vortices, and be sure to check out the diagrams there.
This ferrofluid was subjected to a magnetic field perpendicular to its surface. The surface broke up into hexagonal regions, each with its own spike. For a MIT News article showing other ferrofluid patterns created by the same physicist, see Fluid morphs into startling designs, surprising MIT researchers.
Time Flies - Nov 1, 2011
Einstein's theory of special relativity says that a moving clock, when compared to a stationary clock, runs slow. And general relativity, his theory of gravity, says that the weaker the gravitational field, the faster a clock in that field runs. These predictions were tested in 1971 by flying atomic clocks around the world. Einstein's relativity theories correctly explained what happened.
image credit: National Oceanic and Atmospheric Administration/Department of Commerce; image source; larger image
The Contrail Effect - Oct 1, 2011
The false-color image above shows jet contrails in the skies above the mid-Atlantic coast on 1/26/2001. Check out this NASA photo of the sky taken on the ground at about the same time. Visit The Contrail Effect to find out how contrails can affect Earth's climate, and how this was investigated after 9/11.
How does GPS work? - Sep 1, 2011
The photo shows a Global Positioning System satellite. To find out how the system works, visit How does GPS work?, and be sure to see the video to understand how three or four different GPS satellites specify your position on Earth. For more, check out this Beyond Discovery page from the National Academy of Sciences.