Stabilizing an inverted pendulum

Like many physicists, I have a fondness for simple physical systems that behave in unexpected ways. Here’s a demo known as “Kapitza’s pendulum”.

For those who didn’t watch the video, it shows an ordinary pendulum attached to a motor. Then the motor starts moving up and down 58 times per second. While the motor is running, the pendulum stands upright, and stays upright even when knocked to the side.

Kapitza’s Pendulum is easily understood by anyone with a degree in physics. But for everyone else, here’s an explanation that could be understood with high school physics.

[Read more…]

Linkspam: February 10th, 2017

Time to get back into these monthly linkspams.

Cartomancer on Greek Masculinity – This is a long but worthwhile article on masculinity in ancient Greece.  What’s interesting is that there are multiple masculinities (just as there are today, of course), as illustrated in Achilles and Oddyseus.

The Intersection of Guess Culture and Sex is Rape Culture – The thesis is in the title, and I agree with it.  When consent is important, such as in the realm of sex, then it is important that consent be clear.  I am not exactly sure what the advantages guess culture has over ask culture, but clear communication is certainly not among them.

The Value of a Vote – ExtraTricky calculates the value of a vote based on the probability that it could have flipped the election (according to polling estimates).  In California, our votes are worth 40 times less than the average vote.  I guess… I guess I already knew democracy was dead, and didn’t need math to tell me so.

Ace Tropes – This is a series about tropes in asexual fiction.  I wrote the first six articles, but it is now being continued by the excellent Sara.  I really enjoy writing about tropes because it’s a way to connect to other people over fiction, without having to have read and liked exactly the same fiction.  I live on the long tail of culture, liking things that hardly anyone else likes, but that doesn’t mean we can never talk to each other.

Storybook endings

I recently saw a movie about two people chasing their dreams. The main theme of the movie was pragmatism vs idealism, and the main conflict in their relationship was when the two people drifted apart from each other on that scale. (Yes, the movie in question was La La Land, but this isn’t about that particular movie.)

The thing about this kind of story is that the interpretation depends a lot on the ending. Do the people in fact achieve their dreams? Or does it turn out that their dreams were unrealistic, and that they were better off pursuing more realistic goals? In effect, the ending of the story is an expressed opinion about whether it is better to be pragmatic or idealistic.

As critical viewers, we might disagree with the story’s opinion. For example, if the ending were too idealistic, we might consider it implausible, because we believe most people with such pipe dreams are never able to achieve them. Or if the ending were too pragmatic, we might criticize it as too dark or cynical. Generally, we wouldn’t accuse an unhappy ending of being implausible. We take for granted some optimism in our story endings, and a cynical ending tends to defy our expectations long before it defies belief.
[Read more…]

Meanderings on violent protest

Recently, there was a protest at UC Berkeley, which led the loathsome Breitbart journalist Milo Yiannopoulos to cancel his talk. Some of you may have figured out by now, this is a local story to me. I saw the protest myself.

Well, I only really walked by the protest on my way home. There were maybe a hundred people at 5 pm, but UC Berkeley says it later grew to 1,500. Protestors were chanting “No Milo! No Trump!” There was someone holding a giant dove. I took a flyer, which was produced by refusefascism.org–and then being anti-social I went home and played video games.

Photo of someone holding a giant dove made of cloth and sticks. Another person holds a red flag that says RESIST.Somebody managed to capture the dove. This photo is on the edge of the crowd so it doesn’t tell you how big it was. From Chicago Suntimes, who credits it to Ben Margot/Associated Press.

It was later I heard from Facebook that the protest had turned violent, and the university cancelled the talk. I heard that protestors attacked police, set a portable generator on fire, and then broke a bunch of windows nearby.  There were few minor injuries.

Among my friends, many expressed sympathy for the protest, or were at the protest, but they condemned the violence. They were keen to highlight this particular part of the UC Berkeley statement:

The violence was instigated by a group of about 150 masked agitators who came onto campus and interrupted an otherwise non-violent protest.

[Read more…]

Origami: Six Intersecting Squares

Six Intersecting Squares

Six Intersecting Squares, a model of my own design

Description: 6 squares, each made of four sheets of identically patterned paper.  The squares are organized into three pairs of parallel planes.  Each square has a square hole cut out from the center so that you can see straight through it.

[Read more…]

No words

I am so pissed off by the immigration ban, and all the circumstances surrounding it.  I feel as if the most pessimistic predictions about a Trump presidency are coming to fruition, and the truly morbid ones sound realistic.  Are we currently witnessing the rise of the American Hitler?  The fall of the US?  Is this the prelude to WWIII, this time with nuclear weapons?  Does anything else matter?

When I set out to write a post, I usually start with a potentially contentious point, and build arguments in favor or against it.  But in this situation, there is no contentious thesis, and no one to argue with.  This is unacceptable, and I can’t think of what else to say about it.  I don’t think I could bear to turn it into yet another thesis and essay.  Blogging simply isn’t the right tool to address this problem.

I have a draft, entirely unwritten, where I talk about the value of low-priority activism.  For example, atheist activism is still valuable even though religion isn’t the root of all evil.  Feminism is still important even if not everything can be blamed on the patriarchy.  It’s okay to fight for a thing that is not the most important thing.  Anyway we don’t even know what the most important thing is.  You get the general idea.

I still stand by this thesis, but just this moment I’m not feeling it.  Because right now we do know what the most important thing is, and that is to stop Trump.

My issues with queer-positive atheism

Following my big rant on queer-positive Christianity, I have a much shorter rant on queer-positive atheism. There are fewer things to unpack, but even the smaller issues are important to me, because I interact more frequently with atheists than I do with religious people.

So you’re not a fundamentalist Christian

The number one criticism I have about atheist attitudes towards queer people is that they’re very self-satisfied about it. Yes, we all know you’re way ahead of fundamentalist Christians. We all know you were in favor of same-sex marriage (or opposed to all marriage) before it was cool. Good for you?

As I previously said, one of my major issues with queer-positive Christianity is that they’re starting from very low standards, the standards of Christianity. Atheists have the advantage of being able to scrap Christian standards entirely and build something better. But you’re tossing out your advantage if you’re always comparing your attitudes to those of very religious people.

And I’m not even saying that we as atheists need to be more ashamed of [insert prominent anti-SJ atheist here]. Shame is not what I’m going for at all. It’s just that, even when we’re all on the same page about social justice, social justice is still a thing that takes work and not just lip service.
[Read more…]