Recent content by Front Office

When the wind blows (outside, of course) air pressure in the house changes, up or down, depending. There is no sensible wind motion in the house. But yes, if air were to blow right against the diaphragm, then I agree: there'd be an effect. As for objects moving nearby, that's a question...

Look at this schematic. The distance between the pushrod support and the fulcrum rod is about 2 mm. The laser beam travels about 4 meters from the mirror, so that the angular deflection of the mirror gets multiplied by a factor of about 2,000; when the diaphragm, in its center where the...

I've been wanting for decades, to learn ways to digitize and record data from various experiments, but . . . well, you probably know how daunting certain things can seem upon first consideration, e.g., A-D conversion etc, and then how simple it all is once you learn it. In this instance, I seem...

It's pretty much a moment-to-moment kind of instrument; i.e., you just watch the red spot and see if the bobbing up and down corresponds sounds you can hear, or, as it happens, to wind that is blowing. In that latter case, wind, the pressure variations inside my house look to be on the order of...

It would be neat to record the output of this type of laser-beam-and-mirror system, and then compare its output to other records. But that's not possible with this real-time system.

Acoustic Observatory -- Low-Cost I have built what I call an Atmospheric Acoustic Observatory. It could also be thought of as a high-resolution barometer. There's a write-up on it at http://www.comfortlight.com/baro.htm. It is simple in principle, and it cost only about $50 for the main...

Acoustic Observatory -- Low-Cost Check out my Acoustic Observatory It uses well-known and obvious principles of operation to "see" thunder at great distances. It cost about $50 to build, including the red laser diode -- but not including the front surface mirror which has been lying around my...

The Wikipedia article on the moon says ithat "Ptolemy (90–168 AD)" calculated the distance of the moon as 59 times the Earth's radius and a diameter, which is about the modern value. But Wikipedia doesn't say how Ptolemy did that. An article at http://www.eso.org tells how to calculate the...

In the time before Copernicus introduced the idea that the planets including the Earth orbit the Sun, how were the daily and annual cycles reconciled? I have always assumed that in the Copernican view the Earth orbits the Sun once each year. But not till today did I wonder about the 24-hour...

Vidar, I just tried that. Amazing. It pushed the stream of water away. I saw, on the KJMagnetics site, a magnet depressing the surface of still water. The deflection was made evident by looking at a slant angle of a reflected pattern on the water.

Like on the order of 10-34 second?

I cut a strip of aluminum foil about an inch and a quarter wide by about 6 inches long. I dangled the long end down, in front of a rare Earth magnet on the refrigerator door. The foil deflected slightly when it got near the magnet, finally getting pulled to the magnet. The foil deflected even...

Richard Feynman writes, on page 97 of his primer of quantum electrodynamics, QED: The Strange Theory of Light and Matter, about the interaction of a photon and an electron. He writes: "One way this event can happen is: a photon is absorbed by an electron, the electron continues on a bit, and a...

I just cut a strip of foil, 3 cm by 15 cm, and used a rare Earth magnet to see if there was any attraction. There was. I think there might be a percent or so of iron in the aluminum, perhaps to make it a little more rigid.

I was watching a show the other night about the Large Hadron Collider, and I got to wondering how much force it would take to push two uranium nuclei right up against each other. I figured it would be on the order of a thousandth, maybe a millionth of a pound, which seems like a lot, considering...