Rhett Allain can see physics in everyday life. But for his students at Southeastern Louisiana University, some of the concepts were a bit trickier to grasp. What started as a project to help students better understand his subject has become a popular blog, Dot Physics, on the Wired website.
I spoke recently with Allain about science blogging, teaching physics and answering impossible questions. Below are excerpts from our interview.
Why did you start the Dot Physics blog?
I wanted [my students] to do projects like this. They needed an example. I wrote up two or three example projects, so they could see what I was looking for. Then, things got out of control. I started to come up with other projects. I enjoyed it too much. Initially, it was just a couple of projects for them. But here I am, three years later, still doing it. Last September, [the blog moved to Wired].
How do you come up with post ideas?
There are lots of sources for posts. People email me and ask questions. If it’s a good question, I want to know the answer too. They’re not all questions that I answer. Sometimes I try to explain things. I might be surfing the Internet and find a great video. It could be something on TV or in your house. I write it down. Unfortunately, there are a lot of things I write down that I never get a chance to come back to.
Could you give an example?
There are a lot of things I want to finish. There was a fake video that used a tripod to record motion. That made it easier to edit and put fake stuff in the video. I was convinced the camera motion was fake compared to someone holding a real camera. There were questions that came up that I wanted to look at more. Do different people hold cameras differently? Can you tell who is holding the camera? I have the data. I got my kids and my wife to video the same thing. I want to compare how the motion varied for those. I haven’t gotten around to doing that.
Have there been any questions posed on your blog that were impossible to answer?
I write about impossible things all the time. It depends on the level of impossibility. Is it impossible to get an exact answer? That’s just about everything I do. But you can get a ballpark answer. That’s the cool thing about science.
I did mess up on the post about the speed of falling rain. I had the false assumption that rain drops were rain drop-shaped, which apparently they’re not. Rain doesn’t fall at 500 miles per hour, that’s clear. And it doesn’t fall at one mile per hour. Even using the wrong things, you can get an approximation. That’s one of the things I like to do. You can say: I don’t know everything about this, but I can approximate and see how reasonable it would be.
Who reads your blog?
It’s a mix. The last time I took a census, I was surprised by how many of my regular readers were students. Now, I’m pretty sure it’s different. It depends on the post. I have regular readers. But if I write about whether bird poop can crack a window, I can get a much larger audience just for that post. That’s a completely different population. I suspect most of the people who read it regularly are students and educators and people interested in science.
How much interaction do you have with readers? What do you learn from them?
For comments, it depends on the post. If a post gets popular, I can’t keep up with the comments. [The readers] usually have their own discussions. I do learn a lot from them, like in the case of the falling rain. That was a question a commenter asked. Then, I found out that there are great videos showing the shape of falling rain. Readers can be good sources.
I don’t do a lot of background research on these topics. That’s not my goal. My goal is to take what I know now and get an approximation. It’s not to do a full literature search. The commenters have a large data set of information they can add to that.
Your academic research explores how students understand physics. What can you tell us about the way humans learn and understand physics?
A common thing in the past was to say: That idea is wrong and you shouldn’t have that idea. Now we’re more at the place of saying: That idea doesn’t agree with the evidence, but there’s a reason you believe that idea. You don’t have wrong ideas because you’re crazy. You have wrong ideas for a reason. Let’s build on that.
If you’re pushing an object and you stop pushing it, a lot of people would say that if there’s no force, there’s no motion. That’s not right. But that idea agrees with everything you’ve done in your life, so it does make sense. It’s best not to abandon what those students think, but to start from where they are.
Photo: Rhett Allain