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?

Uncertain Dots, Episode 6

This week’s episode of Uncertain Dots is, if anything, even more free-form than previous weeks, including a brief cameo from one of Rhett’s kids: Topic covered include the arrangement of faculty offices, the relative lack of demos for E&M (compared to mechanics, where there are endless videos to analyze, etc.) a little bit about science… Continue reading Uncertain Dots, Episode 6

Science Journalism vs. Sports Journalism

Over at Backreaction, Bee takes up the eternal question of scientists vs. journalists in exactly the manner you would expect from a physicist: she makes a graph. Several of them, in fact. It’s generally a good analysis of the situation, namely that scientists and journalists disagree about how to maximize information transfer within the constraints… Continue reading Science Journalism vs. Sports Journalism

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