Rhett Allain
rallain
Posts by this author
February 17, 2009
I previously talked about textbooks and how there is clearly a problem. The CK-12 Foundation is trying to do something about this problem with the flexbook. Basically, the flexbook allows teachers to create their own text by combining different free content. You can customize a book that closely…
February 17, 2009
The first thing from AAPT that I would like to mention is SAM Animation that Brian Gravel demonstrated. SAM is free software that allows for the easy creation of stop motion animations. Basically, you use a web camera to take successive pictures and put them together as a movie. The software…
February 17, 2009
A quick note. I am back from the AAPT meeting in Chicago. My first surprise was from my hosting company (lunarpages). They said that I had once again gone over my CPU usage for my site. I am really not sure why and I can't really see my CPU usage. Anyway, the short story is that I either have…
February 15, 2009
Someone complained about a teacher using this question and the answer was disputed. After some time, the teacher claimed that the answer was that lightning is static electricity because she looked it up on the internet. So, I decided to look also, here is what I found searching for "what kind of…
February 13, 2009
The local Society of Physics Students invited me to watch the movie Sunshine and then participate in a post movie discussion. There was one thing in the movie that really got me. Of course the movie made many of the common space mistakes. But this one didn't seem necessary. Let me outline this…
February 12, 2009
Previously, I talked about science fairs. One of the problems is that students don't really have a good understanding of data analysis. For me, statistical analysis is just something to do with data. It isn't absolutely true. So, it doesn't really matter that students use sophisticated tests on…
February 12, 2009
Since this could be current events, I am reposting my analysis of space debris in the movie Wall-E.
Here is a shot from the scene where the space craft is leaving Earth:
In this scene, the spacecraft has to break through all the Earth-based space debris. The first problem is that the unused…
February 10, 2009
Last friday I volunteered as a science fair judge. It took half a day, but I did get free food and tons of things to blog about. There are so many things to say about science fairs that I don't really know where to begin. I actually might not even address all the issues. Here is what I would…
February 7, 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…
February 4, 2009
Not sure if you know what Jump the shark means. I figured it was a common term. Here is the wikipedia entry. Or maybe you would like a graphic explanation. Here it is:
So, why the attack on textbooks? The main reason is that I just posted a rant about forces (or abuse of the word force) and I…
February 3, 2009
People say I am picky. Ok, sometimes I am. But somebody has to stand up for what is right and just. Maybe I am that person.
Please stop using the word force if you don't know what it is.
There. I said it. You can attack me now.
It wasn't just one thing that got me fired up. It was two things…
February 2, 2009
I enjoyed the super bowl commercials for the most part. You have to be careful not to have too high of expectations, or you will set yourself up for a big letdown. Here is a quick analysis of one of the commercials. This is a Bud Light commercial where at the end they throw a guy out of an…
January 30, 2009
I said I would come back to this, and I am. I am a man of my word. Yesterday, I posted a link to a video of this really cool water rocket thingy.
How does this work? What is the physics going on here? I think this can be best explained with the momentum principle.
Let me start by pretending like…
January 30, 2009
Buzz Out Loud is one of my favorite tech podcasts. Unfortunately, I am a little behind in the episodes. However, in the episode 900 there was an email from a listener regarding LHC and black holes. The emailer claims that a massive black hole would mess up Earth's orbit. This is not quite true…
January 29, 2009
I saw this on Hack a Day, but I am sure it has been posted in other places also (seems like something that would be on Swans on Tea). Check it out.
Amazing New Water-Powered Jet Pack - Watch more free videos
Some pretty cool stuff. I am pondering the questions to be answered right now.
January 29, 2009
I really didn't want to post this, but I am going to anyway. I used ScreenToaster.com to make a screen capture movie (with audio) of a tutorial on spreadsheets.
This should accompany my previous post on numerical calculations.
Free online screen recorder
January 27, 2009
We have all seen the Kobe Bryant video of him jumping over an Aston Martin - this keeps coming up on the Internet. There has been vast discussions of whether this is real or fake. I will do my best to examine the evidence. In short (in case you don't want to read the whole thing) Kobe can most…
January 27, 2009
Should you grade on a curve or not? If you are student, the answer is clear: go by whatever the instructor does. Otherwise, you have a choice. I don't like to tell other instructors or faculty what to do because I respect their freedom. For my classes, there is no curve. Why? Well, the…
January 25, 2009
When you pour a beer, there is this foamy top called the head. The size of the head decreases over time. What is this process dependent on? Clearly, little bubbles of beer are popping. Does each bubble have an equal probability of popping? Do only the bubbles on the top (or bottom) pop? I became…
January 25, 2009
When you pour a beer, there is this foamy top called the head. The size of the head decreases over time. What is this process dependent on? Clearly, little bubbles of beer are popping. Does each bubble have an equal probability of popping? Do only the bubbles on the top (or bottom) pop? I…
January 22, 2009
Question: When is the Sun directly overhead? (assume you are in the United States of America)
Common Answers:
Everyday at noon.
On the summer solstice (June 21ish)
Answer: For continental U.S. the answer is never. Since the Earth's rotation axis is tilted 23.5 degrees with respect to its orbital…
January 20, 2009
So, you are taking a college science course. Maybe it is physics, maybe it is chemistry, maybe its a lab. Either way, you always end up with these problems that involve unit conversions. You think you have the hang of it, but sometimes you make some mistakes. Here is my explanation for converting…
January 19, 2009
I just can't pass this up. One of the chemistry majors had a complaint with the power company. After an unusually high previous power bill, they checked the electric meter half way through the month. The meter said they had used 90,000 kilowatt-hrs of electricity. That is a lot of energy. It…
January 18, 2009
Podcasts are great. While cleaning the car today, I listened to a new one - Stuff you missed in history class (itunes link). In one episode, they were talking about alternative theories about early visits to America. There was some guy that was claiming the Chinese visited the new world 70 years…
January 16, 2009
It has been windy here lately. Sometimes I think that is an ok thing. You see, when I ride my bike to work I am probably going to have the wind at my back for one of directions. It is great feeling like Lance Armstrong because of the boost you get from the wind. With a good wind at my back, I…
January 14, 2009
I just finished my first class of "Physics for Elementary Education Majors". The maximum size for the class is 32 students and it is very interactive. I make it a point to learn student names as quickly as possible. This is something I am terrible at.
Should you memorize names? If it is a…
January 13, 2009
I was going to title this post "Blog-a-lama-ding-dong" but I read somewhere that the title should be very descriptive (for better search optimization). So, my brother decided to start a blog. He was looking for some direction. I am by no means an expert blogger, but I do have some ideas about…
January 12, 2009
I am not going to try and even surprise you with this. Notice the "tools:". This post is not about physics really, but something used in physics. When I get enough of these, I will put them together in a "tools" page - or you can just use the tools-tag.
Suppose you have some data. You want to…
January 12, 2009
I am getting ready for classes. One class I am teaching is a physics course for elementary education majors. I really enjoy this class. There is hardly any math and the students learn by doing some experiments and then creating models. These models are then shared and discussed among the class…
January 10, 2009
So, here is a video (from break.com - so you know it is likely fake).
null - Watch more free videos
If for some reason, you can not view this video, here is the plot.
Guy wears parachute and brings a portable thing like a see-saw.
Guy approaches large crane dropping a large mass repeatedly (I…