May 21, 2011 14 Comments
In this video, I’m discussing “socially responsible” investing with the mathematician from http://askamathematician.com. If you limit your investments to companies that uphold ethical principles you care about — for example, environmental protection, human rights, diversity, etc. — how much of an impact does your investment decision have?
May 12, 2011 7 Comments
Last week I stumbled upon that beautiful pendulum video. In comments, Max shared another cool video from the same people (Harvard Natural Sciences Lecture Demonstrations) – about synchronizing metronomes: (Thanks Max!)
The audio effect is important; watching the metronomes isn’t as powerful as hearing them get in a rhythm.
Any variation between the metronomes results in energy “swaying” the system, leading them to synchronize over time. After all, you wouldn’t expect a metronome to keep perfect time if you were shaking it – the setup just makes the shaking work against metronomes going against the consensus. I’m sure our friends at Ask a Mathematician/Ask a Physicist could give a more thorough answer.
What surprised me is that they got OUT of synch after being removed from the soda cans. I thought that, once in a rhythm, they would stay that way. I guess that by picking the system up and putting it back on the table was enough to break that. Or am I missing something?
May 10, 2011 25 Comments
In this week’s video, I field a question about a tricky dilemma in moral philosophy: if you had to kill one innocent person to save five people, should you do it?
May 4, 2011 15 Comments
This is one of the simplest but most captivating physics videos I’ve ever seen:
Each pendulum is at a slightly different length – not just for the visual effect, but it gives them different phasesperiods/frequencies [Seth, the Physicist in Ask a Mathematician/Ask a Physicist wrote me to correct this – Thanks Seth!]
Fifteen uncoupled simple pendulums of monotonically increasing lengths dance together to produce visual traveling waves, standing waves, beating, and random motion.
For more details see http://sciencedemonstrations.fas.harvard.edu/icb/icb.do?keyword=k16940&pa…
The period of one complete cycle of the dance is 60 seconds. The length of the longest pendulum has been adjusted so that it executes 51 oscillations in this 60 second period. The length of each successive shorter pendulum is carefully adjusted so that it executes one additional oscillation in this period. Thus, the 15th pendulum (shortest) undergoes 65 oscillations.
This seems easy enough for middle school students to set up and learn from. Our friends at Ask a Mathematician/Ask a Physicist just had a post: Cheap experiments and demonstrations for kids. I think this would be a great addition.
(Via Richard Wiseman)
April 27, 2011 34 Comments
In this week’s video I discuss my new favorite word — “Granfalloon” — and how identifying yourself with a particular group can distort your thinking.
April 25, 2011 8 Comments
Randall Munroe's infographic on radiation dose levels (Click to enlarge)
I’m a huge fan of clever ways of visualizing data, especially when there’s something challenging about the data in question. For example, if it contains more than three important dimensions and therefore can’t be easily graphed with the typical representations (e.g., position on x-axis, position on y-axis, color of dot). Or if it contains a few huge outliers which distort the scale of the data.
This recent infographic in Scientific American by my friend (and co-blogger, at Rationally Speaking) Lena Groeger is a great example of the latter. The challenge in displaying relative levels of radioactivity is that there are a few outliers (e.g., Chernobyl) which are so many times higher than the rest of the data that when you try to graph them on the same scale, you end up with the outlier at one end and then all the rest of the data clumped together in an indeterminate mass at the other end.
Randall Munroe over at the webcomic XKCD came up with a pretty good, inventive solution that relies on our intuitive sense of area, rather than length. Each successive grid represents only one small block of the next grid, which is how he manages to cram the entire skewed scale into one page. It’s cool, but I don’t think it works that intuitively. We have to consciously keep in mind the reminder of how big each grid is relative to the next, and it’s easy to lose your grip on the relative scales involved.
However, one of the benefits of online infographics as opposed to print is that you don’t have to fit the whole image in view at once. Lena and her colleagues created a long, leisurely scale that has the space at one end to show the differences between various low levels of radiation dose, below 100,000 micro-Sieverts… and then it hits you with a sense of relative magnitude as you have to scroll down, down, down, until you get to Chernobyl at 6 million micro-Sieverts.
It reminded me of one of my all-time favorite data visualizations: over one hundred years of housing prices, transformed into a first-person perspective roller coaster ride. There are a number of wonderful things about this design choice. For one thing, it works on a visceral level: reaching unprecedented heights actually makes you feel giddy, and sudden steep declines are a little scary.
I also love the way it captures the most recent housing bubble — as you keep climbing higher, and higher, and higher, and higher, and higher, the repetitive climb starts to feel relaxing, and you even forget that you’re on a roller coaster. You forget, in other words, that you’re not going to keep going up forever. And that moment at the end, when the coaster pauses and you turn around to look down at how far away the ground is (this video stops right before the 2008 crash) — shiver. Just perfect.
April 20, 2011 17 Comments
In this week’s video blog, I talk about why it’s important to be able to spot your own rationalizations, and tricks to help you do so:
April 13, 2011 2 Comments
Looking around, we can see incredible levels of complexity in our world. Fascinatingly, things seem to have been getting more complex in our immediate surroundings. Starting with the Big Bang, David Christian gives a delightful TED Talk on how complexity has increased. His “Big History” approach focuses on the times that conditions were just right to pass ‘thresholds’, allowing new forms of complexity – more complex particles, life, and information.
I loved the way he weaved physics, chemistry, and biology into a continuous story. Slight variations at the beginning of the universe led to stars, which lead to diverse elements and the formation of planets, which (at least once, here) had the right conditions for life. More importantly, the conditions had to drift/develop into a narrow window for the next level of complexity to develop. Dense but not too dense, hot but not too hot, stable but not too stable.
That was a point which stood out to me – the conditions didn’t START perfectly for complexity right off the bat. After all, it’s been over 13 billion years. They changed slowly, with billions of slightly varying instances, and when the threshold was passed it triggered a cascade.
I got the sense that some of the transitions involved hand-waving, but I grant it’s not exactly easy to compress the history of the universe into 17 minutes.
His next step caught me a bit off guard though (around the 15:30 mark):
This is a powerful story. And it’s a story in which humans play an astonishing and creative role. But it also contains warnings. Collective learning is a very, very powerful force, and it’s not clear that we humans are in charge of it.
He goes on to raise the point that our collective learning is so powerful that we have the power to ruin the “Goldilocks Conditions” for increased complexity. Our discovery of nuclear weapons and overuse of fossil fuels could lead to dramatic shifts in our capacity for advancement.
I’m not sure that I like the word choice, implying that some other entity is ‘in charge of’ the story. Perhaps he meant to imply that humans might not be in full *control* of our power. Looking at the irrationalities of human thought and decision-making, it’s certainly possible that we’ll misuse the power with catastrophic results.
Nothing about the story implies that complexity is guaranteed to increase or that it’s necessarily a good thing (topics for another time). But it’s interesting to look at the various ways that conditions became *just* right to allow us to reach this stage, and what might end it.
If it weren’t for the anthropic principle you might start to get ideas…
(h/t Hemant at the Friendly Atheist)
April 1, 2011 4 Comments
We must be on our guard when people are making misleading medical claims to children. Fortunately, Katie Couric has the courage to investigate and expose the lies. Watch her expose the so-called cure “Shake the Sillies Out”:
It’s a song you’re probably familiar with. “Shake your Sillies Out” is easy to learn and adorable to watch. But according to new research, there’s only one problem: It doesn’t work.
Watching her interact with the kids was priceless: “What would you do if I told you that those things don’t work? In fact, there is zero scientific evidence that you can [dramatically puts on glasses] jump your jigglies out, squiggle your squirmies out, or even wiggle your waggles away. You’re living a lie.”
Now, if only we could get the mainstream media to report like this on real scientific quackery…
March 29, 2011 11 Comments
In this week’s video, I explain what I mean by “rational,” and discuss some of the other meanings that people attribute to this often-ambiguous word.
Looking around, we can see incredible levels of complexity in our world. Fascinatingly, things seem to have been getting more complex in our immediate surroundings. Starting with the Big Bang, David Christian gives a delightful TED Talk on how complexity has increased. His “Big History” approach focuses on the times that conditions were just right to pass ‘thresholds’, allowing new forms of complexity – more complex particles, life, and information.