Built on Facts

Archives for June, 2009

Normandy

Our landings have failed and I have withdrawn the troops. My decision to attack at this time and place was based on the best information available. The troops, the air and the Navy did all that bravery could do. If any blame or fault attaches to the attempt it is mine alone. – Gen. Dwight…

VERY Long Distance Rocketry

I don’t know if you’ve been reading Photo Synthesis, but if you haven’t you’re missing a real treat. Currently there’s some incredible photography and video of amateur rocketry at fairly large scales. Amazing stuff. A hundred years ago the idea that an amateur of comparatively middle-class means (well, after a lot of saving anyway) could…

Black Holes & Sound

Reader Abby Normal(!) writes in with an excellent question: Something in your post about Physics in Star Trek, May 18, 2009, has been bouncing around my brain. You stated that a black hole has the same mass, and therefore gravitational pull, as it’s parent body. That makes perfect sense. But as I understand it a…

Tennis & Trajectories

There’s many, many sports out in the world that involve sharply hitting a ball with something. Baseball, tennis, golf, cricket, polo, you name it. After being hit, a ball describes a trajectory determined by the gravity of the earth and the interaction of the ball with the atmosphere. This can be exploited in many sports,…

All right ladies and gentlemen, today we’re performing an experiment! More of a demonstration, really, but one that’s very easy and will impress your friends. You will need: 1) One remote control. 2) One camera phone. The vast majority of remote controls operate via an infrared light-emitting diode situated at the front of the device.…

It’s My Ritz in a Box.

This is the conclusion of the Ritz variation discussion we’ve been doing. Tomorrow we’ll get back to less arcane and more entertaining physics, I promise! We’re capping things off today by demonstrating the actual technique in detail for an example where we already know the answer. What we’re doing is finding the ground state of…