Rhett Allain
rallain
Posts by this author
September 9, 2009
I love this question:
Why is it warmer in the summer than in the winter (for the Northern hemisphere)?
Go ahead and ask your friends. I suppose they will give one of the following likely answers:
The tilt of the Earth
The tilt of the Earth makes us closer to the Sun
We are closer to the Sun
Really…
September 8, 2009
Here is a quick story. A faculty member came to me last week disappointed about the introductory physics students' lack of understanding with regard to electric potential. Let me call the faculty Beta, because I think that would be a cool name. Beta was disturbed that the students didn't get…
September 4, 2009
I love this story. It is a story of how ideas changed about the nature of the atom. These are the notes (and diagrams) I use when I teach the atomic nature of matter to non-science majors. The best thing about this story is that it is a great example of science. Science (or scientists) build a…
September 2, 2009
Students are starting to get the flu around here - and that means that it is time to debate. Clearly there are going to be some absences in the coming month. The question is: what to do about it? There are two camps of thought here:
Camp 1: Excuses are bad
This camp of faculty is worried. They…
August 31, 2009
Maybe this is a little old (in internet age), but it is a great example. Here is the Loop-the-loop stunt from the show Fifth Gear.
I like this. First, it is a bold stunt. But also, there is some good physics here. Though, most importantly, the Fifth Gear producers were kind enough to include a…
August 28, 2009
I found this in the most recent issue of The Physics Teacher (September 2009). Surprisingly, there were several good articles in this issue. One article discusses a doable version of the Millikan Oil drop experiment. Maybe you are not a (or were not) a physics major, so you might not be familiar…
August 26, 2009
I re-watched Harry Potter and the Order of the Phoenix last night and my wife and I noticed something about teaching. Of course I mentioned that this would make a good blog post (and she may still post it on her blog, but I can't help myself). If you have not read the book or seen the movie, I…
August 23, 2009
I saw this video on digg or reddit. I can't remember which.
I was in awe. Then I started thinking. I wonder how fast that water was moving up right after the explosion. Too bad the video doesn't have a scale. Well, it kind of does - there is that ship. I am terrible at ship identification…
August 22, 2009
I found this link on twitter from New Scientist.
'iTunes university' better than the real thing
This pretty much sums it up:
"Students have been handed another excuse to skip class from an unusual quarter. New psychological research suggests that university students who download a podcast lecture…
August 21, 2009
Forgive me if I don't know the official parkour term for this move. This is where you have two walls that are close to each other and you vertically climb them. Here is a shot of Mark Witmer (from Ninja Warrior) doing the wall climb.
Doesn't look too hard, does it? Well, I think it depends on…
August 18, 2009
I got this question. How does this game work? Really, this is one of those silly things that gets forwarded a lot. It is called Regifting Robin. The basic idea is:
pick a 2 digit number, like 37
subtract both the number in the tens place and the number in the ones place from the original number…
August 18, 2009
I wrote two letters (for two different classes). These are letters from the students of the near future to themselves in the present. this first one is for a non-majors lab. In this lab, I let them turn in "informal" lab reports that they can then use on the midterm and the final exam. The…
August 17, 2009
I have been reflecting on my recent failure to realize that the Giant Water Slide Jump was fake (more analysis here). I think the guys that made this video did a really good job on several levels. First, the motion appears to do two important things:
shows constant acceleration in the vertical…
August 17, 2009
This is amazing. I can't believe that power companies are paying Blacklight Power money, but they are. I guess Blacklight Power must have great advertising. Ok, so what is this whole Blacklight-hyrdino thing? Honestly, I am not fully familiar with it, but basically this guy says that you can…
August 13, 2009
What's the deal with the Chevy Volt? Well, obviously, it is a cool car. A plug-in hybrid. The problem is in how to quantify its efficiency. Normal hybrids (the non-plug in type) have only one type of energy input, gasoline. The Volt can take gasoline or electricity input. This makes it…
August 12, 2009
This Giant water slide video is extremely popular on the internets. Maybe you have not seen it (doubtful), then here it is:
This is such an incredible stunt that the very first question that comes up is - fake? or not fake? From my previous analysis, I can say:
Even though there is some slight…
August 7, 2009
I have previously compared Tracker Video Analysis and Logger Pro - check that out here. Really, the only advantage Logger Pro has over Tracker is that maybe it is easier to use for simple things and maybe students are already familiar with it from other analysis.
There are other video analysis…
August 6, 2009
Thanks to Nick for showing me this video (Check out his blog - Fine Structure):
See more funny videos and TBT Videos at Today's Big Thing.
Wow. That was my first reaction. My second reaction was: no way. Is this real life? I just don't know. How hard would it be to find out exactly where to…
August 5, 2009
I keep saying the same stuff over and over when it comes to analyzing videos. I can't immediately find a post that lists what makes a video acceptable for analysis, so I will just reproduce on here. I will give 1 point for each of the following that the video has:
Stationary camera and background…
August 5, 2009
Parkour: the act of running and jumping like a crazy superhero. I can't do any of it. But I can analyze it. So, let me start with the wall-flip (or any kind of move that involves walking on vertical walls). This looks like a good example (there are a bajillion on youtube).
Pretty cool, huh?…
August 4, 2009
Check this out (saw it on the interwebs):
It's this video inside a bus of a girl hitting the roof. My first thought was: well, she just jumped. But something was odd. She was in the air too long. Well, of course this calls for a video analysis (using Tracker Video Analysis). Actually, it is a…
August 3, 2009
Every introductory astronomy text and most intro physics texts talk about tides. The usual explanation is something along the lines of:
The moon exerts a gravitational force on the Earth and all the stuff on the Earth.
This force decreases with distance (1/r2).
Thus the moon pulls greater on one…
July 31, 2009
Two things. First, my wife started blogging. The best thing about this is that she can no longer complain about my blogging. Her blog is over at HyperHomeschool.com. Basically, she is keeping up with her homeschooling stuff online. I see great potential here.
I guess this gets to the second…
July 30, 2009
The fall semester is coming up soon. Some students will be taking physics in college. So, here are some pre-class tips - mainly aimed at college students taking algebra-based physics.
Are you afraid?
If you are reading this, maybe you found it because you were looking for stuff on physics. Maybe…
July 30, 2009
Still moving stuff over from my last server. Here is one that keeps coming up.
Surprisingly, I STILL get comments and questions from students and teachers about Pluto. Questions such as:
"Why do scientists hate Pluto?"
"How did they discover that Pluto was not a planet"
"What will happen to our…
July 29, 2009
I am not a programmer. Just to be clear. I use python to get things done, but I am sure it could be done in more efficient ways. Anyway, I sure you know how much I like vpython - especially for teaching physics. However, sometimes I use it for blogging stuff also. The problem is that vpython…
July 29, 2009
You have no idea how long I have been sitting on this one. I made some videos like a billion years ago, and still no post. Why? Oh well, here it is.
I like video analysis of motion. I like looking at stuff on youtube or other video sites. But sometimes, you need to make the video yourself.…
July 28, 2009
Thanks to reader Cleon for notifying me of this video on youtube. Check it out.
First, some notes.
I am sure you noticed that the aspect ratio is incorrect (at least that was the first thing I noticed). The boys must have made a 16:9 video, but then uploaded it to youtube as a 4:3. This doesn't…
July 27, 2009
Sciencegeekgirl is blogging from the AAPT. She talks about showing something interesting to get students thinking, and here is her example:
This reminds me of Dan Meyer's What Can You Do With This stuff. Anyway, I can't help it. I must analyze this video. Plus, Fran essentially threw down the…
July 25, 2009
Here is an interesting article from Mashable: In the Future, the Cost of Education will be Zero
In the article, the author Josh makes the following points:
College is expensive and some people can't really afford it.
There is a growing trend in online universities. University of the People is one…