Rhett Allain
rallain
Posts by this author
January 31, 2010
This is really random, but quick. I was channel surfing and saw the end of the movie: Fantastic 4 - Rise of the Silver Surfer. SPOILER: At the end someone really big explodes in space. There, that wasn't too much of a spoiler, was it? (unless you read the title)
I know I am a loser. I…
January 30, 2010
After judging the science fair last week, I would like to revisit my tips for you the science fair participant.
Warning number 1
Some of the things I say here might go against what your teacher has told you. I am not sure what you should do in this case. Your teacher gives you a grade and I am…
January 27, 2010
Here, I am referring to Dan Meyer's "Be Less Helpful" mantra. I like it, but maybe you aren't familiar with Dan. Here is his take on a high school physics problem. Or maybe you would like the video version:
Be Less Helpful - CMC North 2009 - Dan Meyer from Dan Meyer on Vimeo.
What does this have…
January 27, 2010
This is actually been sitting around for a while waiting for me to post it. Here is another short Christmas-toy demo. I am going to pull this yo-yo at different angles and on two different surfaces. Check it out.
What is going on here? Let me look at the first case where I pull the yo-yo and it…
January 26, 2010
This is one of my favorite things to do in class. I don't do it too often, or it would lose its specialness. Probably the best time to do this is near the end of class.
I pass out half-sheets of blank scrap paper. Students are told to write a question on the paper and turn it in. The question…
January 25, 2010
There is a question that keeps coming up in discussions I have. "What should elementary students study in science?" Probably the best answer to this question is: something other than what they are doing now.
What do I think students should know about science? Should they learn how to calculate…
January 22, 2010
Since my previous post on R2-D2 flying was so popular, I thought I would follow it up. I was going to add these two points in the comments, but a separate post seems to make more sense.
Point 1 - R2 flies at a constant speed
Well, he obviously doesn't always have to fly at a constant speed.…
January 21, 2010
You know I can't help but like Star Wars. Even with the new stuff, I watch it. Recently, I was watching the Clone Wars cartoon and noticed something odd about the way R2-D2 flies. I know what you are saying...."the odd thing is that he flies at all. Why didn't he fly in episodes 4-6?" Who…
January 20, 2010
I stumbled on this flash game Bloons. The basic idea is that you (the monkey) throw these darts and try to pop some balloons.
Well, what is the motion of these darts like? Is it constant acceleration? Time to pull out the free and awesome Tracker Video Analysis.
I threw a few shots and captured…
January 20, 2010
It is not exactly finished, but I have moved over all of my old posts from my previous site. If you want to browse, feel free to look at the archives. Some of those are not too interesting, so I will just list the pages with the most views (but I will leave out my 12 reposts from Christmas).
The…
January 19, 2010
Today is show-n-tell day (at least for this blog). Our department (Chemistry and Physics) has recently been focusing on increasing our undergraduate enrollment. One of the steps we have taken is to have the following video created. I think it is pretty good.
Southeastern Louisiana University…
January 19, 2010
My dad and I had a disagreement. We were driving back from a trip and he let me take over the wheel for a while. His complaint was that I was driving too slow and it was driving him crazy. For me, I thought I was driving fast. My typical behavior is to drive 3 mph under the speed limit. That is…
January 14, 2010
Here is a picture of something you have seen before.
These are two pictures of the same location in my house. The one on the left is taken when the Sun was up outside and the other one when it was dark outside. For both pictures, I had the same lights turned on inside. So, why does it do this…
January 14, 2010
If you know me, you know I love Tracker Video Analysis. Basically, it is a free-java program that allows you to get position-time data of a moving object from a video. In Tracker version 3.10, there is now the autotracker feature. This will automagically mark the location of an object moving in…
January 13, 2010
Check out this picture.
These camera flashes are just awesome (well, they look awesome). They are not a very useful thing for pictures in this case. Here is the problem. Well, first here is what the flash on a camera is supposed to do. Suppose there is a camera and a ball in a dark room. In…
January 12, 2010
I hate to be left out. ScienceBlogs, Starts with Bang has started a fitness theme that we are encouraged to participate in. I like to participate. I even had some good ideas. Here is what I was thinking:
Look at the physics of Wii-fit (actually, this one is good, I should come back to it…
January 12, 2010
In a MythBusters episode some time ago, Adam and Jamie jumped off a building. There was some cool stuff in this, but I want to focus on the acceleration data they collected. Before jumping into a pit of foam, they first wanted to test the set up by dropping a dummy into it and measuring the…
January 11, 2010
I am totally ready to get back to blogging. In fact, I have a post that is 3/4th complete that I have been working on since before Christmas. Anyway, in order to procrastinate a little bit more I would like to share two learning observations (maybe they are not really about learning).
Kids these…
January 4, 2010
This is great. Many people have already reported google's apple-dropping homepage in honor Newton's birthday. In case it disappears, here is a screen shot.
So, I got this awesome note from Dale Basler. He said that his class had analyzed this falling apple animation. What a very Dot Physics-y…
January 3, 2010
Wow. In xkcd 681 comic, there is an impressive illustration of the common term "gravity well". Here is a small part of that large image:
I can't resist. I must talk about this awesome illustration. My goal for this post is to help someone understand that comic (although the comic itself does a…
January 2, 2010
I have been meaning to write about this for quite some time. Really, I wanted to reply to Chad's article on science at Uncertain Principles, but you know how things go. So, here are my key and interesting points about science in random order.
Science is all about models (not ball bearings)…
January 1, 2010
It's odd that I have talked about these forces so much. First, I talked about how centrifugal forces were not real and the difference between centrifugal and centripetal forces. Then I talked about how sometimes, fake forces are good. Finally, I talked about the origin of the words centrifugal…
December 31, 2009
My brother started blogging. I encourage this kind of behavior. His blog (bluerope.org) is mostly about cocoa programming (which he seems to be fairly competent at). Anyway, I wrote this comment on his first post.
"I applaud your effort to begin a blog again. If everyone had a blog, this world (…
December 31, 2009
A couple of commenters expressed concern over the use of centrifugal force after my rant on the use of the word force. So, what is the deal with these two terms? Are they ok to use? Are they real forces?
First, are they real forces?
It depends on what you mean by real. What is a force? Here is…
December 30, 2009
Some time ago, I wrote about the awesome things the Greeks did in astronomy. Basically they calculated the size of the Earth, distance and size of the moon and distance and size of the sun. The value obtained for the distance to the sun was a bit off, but still a bang up job if you ask me. (where…
December 29, 2009
I saw this post about Panasonic's home battery. The claim is that this will lead a battery that can power a house for a week. I wonder if I can estimate how big this battery would be.
First - to estimate the energy a house consumes. My first approximation is that you could probably run a house…
December 29, 2009
This idea comes from my friend Thomas. His son is like mine in that they both think LEGO are awesome, and they are correct. For some reason, Thomas decided to calculate the price per piece of LEGO in each set. To promote repeatability, I decided to do this also. Looking at the catalog at LEGO.…
December 28, 2009
What happens when your kids won't give you a turn on the Wii? Simple. You take their LEGO bricks and their slinky and do some physics. I will keep this simple. Basically, I created a slinky holder out of LEGO pieces and added LEGO bricks to the end to stretch it. Here is the video.
Lego +…
December 28, 2009
One of things I like to think about in science is "how do we know that?" It is interesting how one thing builds on another. This is a story of how the Greeks estimated the distance from the Earth to the Sun (an important idea in the development of the model of the solar system). I like this story…
December 27, 2009
In part I of this post, I talked about the basics of projectile motion with no air resistance. Also in that post, I showed that (without air resistance) the angle to throw a ball for maximum range is 45 degrees. When throwing a football, there is some air resistance this means that 45 degree is…