The Sound of Simulated Bombs

Diagram of a falling bomb, showing the components of velocity.

So, last week I idly wondered about the canonical falling-bomb whistle. The was originally intended to be a very short post just asking the question, but I got caught up in thinking about it, and it ended up being more substantial. And leaving room for further investigation in the form of, you guessed it, VPython… Continue reading The Sound of Simulated Bombs

Idle Physics Query: Whistling Bombs

SteelyKid and The Pip, gangstas.

Not that long ago, SteelyKid was doing something violent with toys (she’s very tough, as you can see from the featured image above), and in the process made the canonical falling-bomb whistle noise. And it occurred to me to wonder, why that sound? I mean, I’ve seen footage of falling bombs and the canonical sound… Continue reading Idle Physics Query: Whistling Bombs

What Is Color?

Spots from 660nm and 405nm laser pointers, partially overlapping. We perceive a new color in the overlap region, because of the way our eyes process color.

This year’s “Flame Challenge” asks scientists to explain color in terms an 11-year-old can understand. The rules limit answers to either 300 words of text or a 6-minute video. 300 words is ridiculously short, so video is clearly the way to go. Of course, I’m not much of a video expert, but then, one of… Continue reading What Is Color?

What Is the Resistance of an Instek GDM 396 Current Meter?

A long chain of current meters, used to determine the resistance of a single meter.

Last week, we looked at the resistance of a voltage sensor by using the discharge of a capacitor, getting a value that was a bit high, but not wildly out of line with the specs. This time out, we’re going to look at the resistance of a current meter, because some students asked about it… Continue reading What Is the Resistance of an Instek GDM 396 Current Meter?

What Is the Resistance of a PASCO 750 Interface Box?

The incredibly sophisticated apparatus used for this experiment.

For the latest in our ongoing series of post where I overthink simple questions, I’d like to present the longest single continuous experiment in Uncertain Principles history, which took six and a half hours yesterday. All to answer the question in the post title. This may seem like a waste, given that I could download… Continue reading What Is the Resistance of a PASCO 750 Interface Box?

Computers and Shades

My polarized sunglasses in front of my desktop monitor.

In comments to the post on computer display colors, Will Slaton notes that Mac displays emit polarized light. And, indeed, this is an inherent part of the backlit LCD technology– the individual pixels are bits of liquid crystal between two polarizers, and an applied voltage causes the liquid crystal molecules to flip between a state… Continue reading Computers and Shades

Long Overdue Snow Physics Post

Snow hanging off the edge of SteelyKid's playset.

Ages and ages ago, I posted the picture that’s the “featured image” above, and asked people to submit physics comments about it. Then I got distracted by a series of shiny things, and never did anything with the handful of responses I got. Because I’m a Terrible Person. Anyway, it’s long overdue, but here are… Continue reading Long Overdue Snow Physics Post

On Computer Color

My phone, laptop, and iPad showing off their blues.

This year’s “Flame Challenge” is to explain color in terms an 11-year-old can follow. I have opinions on this subject, a background in AMO physics, and access to scientific equipment, so I’m putting something together. In the course of this, though, it occurred to me to wonder how my different portable computing devices process color.… Continue reading On Computer Color

On the Steering of Sleds

Matt Wolbach sliding through a turn on the luge course in Park City, Utah in 2010. Photo from http://commons.wikimedia.org/wiki/File:Matt_Curve-6.JPG

In the previous post about luge, I mentioned that there was one thing that came up when Rhett and I were talking about this, namely why there are differences in times between racers. The toy physics model I set up last time suggests that the difference between riders is only a matter of aerodynamics– two… Continue reading On the Steering of Sleds