Built on Facts

Archives for October, 2009

Physics and insomina

There’s an interesting article in New Scientist that purports to describe “seven questions that keep physicists up at night”. The list is very heavy on the “deep questions” that tend to percolate around the more esoteric quarters of the high-energy physics world, and not so much on the vast bulk of physicists who (ad Chad…

Book-throwing and physics.

Grab a book, or an empty DVD case, or anything else that’s a uniform rectangular solid. If it’s a book, you might want to secure the book closed with tape or a very lightweight clip, because we’ll be throwing it in the air. We want to test a theory. In classical mechanics we know that…

Football and Trick Questions

There’s a stereotype that it’s declasse for us intellectual aesthetes to enjoy football, but I don’t care. I enjoy it anyway. Whether you spent any time this weekend watching football or not, I’d like to pose a quick and (maybe!) easy vaguely football-related problem to exercise your brain to make up for all the boob…

Deep Physics

The deserts of New Mexico can get blazingly hot and bone-chillingly cold, extremes of temperature familiar to the outdoorsman in that kind of terrain. A few hundred feet below the ground in Carlsbad Caverns, the temperature is essentially stable in the mid-50s no matter how scorching or frigid the air a few feet above happens…

Myth Confirmed.

There’s a question that gets posed toward the beginning of intro physics classes to gauge the students’ understanding of acceleration. If you fire a bullet horizontally while at the same instant dropping a bullet from the same height, which hits the ground first? The point is to think clearly about the equation describing accelerated motion.…

Sunday Function

Edit: The previous version of this post required some fixing, as I boneheadedly mixed up the O and Ω notations. The rest of it should still be good. When you invest in stocks, bonds, mutual funds, or just about any other major investment vehicle, you’ll hear a standard but important disclaimer. “Past performance is not…

Obama comes to town.

Today Texas A&M was a bit of a madhouse. Huge crowds, hundreds of police, unseasonably-suited and grim-faced men with mirrored sunglasses, unmarked helicopters circling overhead, TV cameras circling below, and completely borked traffic. Why? Not just one but two Presidents of the United States are making speeches this afternoon. Obviously most of the fuss is…

A Pound of Electrons?

I propose a Fermi Problem. Over the lifetime of an average light bulb, what is the total mass of all the electrons that have flowed through? Work on that if you have an idea how to proceed, or just take your best plausible guess. Remember it’s a Fermi problem, so we’re looking for estimates rather…

Higgs Hates Us?

Supposedly there’s no such thing as bad publicity, and indeed just about every large organization from business to charity spends tremendous amount of time and money trying to get noticed by the public. You’d think therefore that it would be a good thing that particle physics gets the press it does. You’d think, but then…

Sunday Function

All right, here’s a fun one. It usually comes as part of a story. The story as told is mostly true, though a few details have been a little fudged by the winds of history. It goes like this: when the young Carl Gauss was a small child in school, his teacher wished to kill…