rallain | June 24, 2009The internet sure can bring some awesome stuff. Chad at Uncertain Principles has a great post about the vision of elves. He refers to a part of The Two Towers where Legolas can count the number of riders of Rohan from a great distance.
Not only is the post great, make sure you read the comments also. Very impressive discussion.
rallain | June 23, 2009This was on my 'to do' list, but Tom at Swans on Tea beat me to it. Basically, this grocery store has these plates that when depressed produce electrical energy. Tom does a good job pointing out that this is not free energy (the original article says this also). Clearly, the energy comes from the cars. How much would this cost the cars?
As always, let me start with some assumptions.
The original article says that the bumps will generate 30 kW of energy every hour. That is an odd thing to say. I am going to interpret that as 30 kW of power for all hours (every hour). They couldn't have…
rallain | June 22, 2009Note: This is an old post from the time before my blog was in wordpress. I noticed there was some incoming link for this, and I never moved it over. Here it is in it's unaltered (except for this part) format.
I don't know why I even suggest a new energy source. Fusion power is only a few years away in the future (just like it as always been). This will replace any other sources of energy that we could come up with. But, I can't help myself, I need to share my idea and save the world. It's what I do. (call me a superhero is you want).
We can get all of our energy from the rotation of the…
rallain | June 22, 2009Maybe this isn't the best video to analyze, but it sure is funny. I am not sure why it is so funny - maybe you should just watch it first.
Sledgehammer Funby Stressmaker
I don't really know why these guys are putting explosive on sledge hammers. Sure it looks fun, but I think I would pass. Anyway, here is the part I was curious about.
Did the exploding hammer lift him off the ground, or did he jump as a reaction to the explosion. It kind of looks like he was lifted, but I am not sure that is possible. Video analysis to the rescue. (using Tracker Video) So, I assumed the sledge hammer…
rallain | June 19, 2009I have been wanting to look at this whole curved bullet thing, but I wasn't sure how to approach it. In case you are familiar with the myth, this is from the movie WANTED (which I did not see). Apparently, some people learn how to make bullets curve by moving their gun. Here is a shot of a bullet curving in front of someone.
Maybe the picture doesn't do the clip justice, but it is enough for you to get an idea. Before I do an analysis, this reminds me of a great educational activity. In the activity, you give groups of students a full sheet of paper with lines that look something like…
rallain | June 18, 2009Ok, this is a post about a particular curriculum, in particular Physics for Everyday Thinking. Let me start with a story.
Some time ago, our college of education was going through an NCATE accreditation review. For some reason, they needed a science course that was just for education majors. As it so happens, we (the department of Chemistry and Physics) already had a similar course that was in the catalog, but no longer being taught. So, we resurrected this course. I was in charge of the curriculum.
The course is a 5 contact hour (4 credit) course that counts for both a lecture and a lab…
rallain | June 13, 2009Our German friends let us borrow their son's bike after he got too big for it. I guess it will still be called a "bike" because it has two wheels.
See. No pedals. We don't need no stinkin pedals. Really, this is a great way for kids to learn how to ride. They just start off kind of walking while sitting on it. As they go faster, they kind of get the hang of how to not fall over. As I have said before, this is counter intuitive - if you are falling to the right, turn to the right.
I don't know if you can get a bike like this in the U.S., maybe you just need to find a German friend. If…
rallain | June 12, 2009Jennifer over at Cocktail Party Physics has a nice post about her trip to Disneyland. The one ride that would be fun to play with (in terms of physics) would be the tower of terror. Think of the cool things you could do with a video camera during that ride. It would be like a mini-vomit-comet. Anyway, I want to talk about one part of Jennifer's post.
"As one would expect, this lifted us out of our seats slightly, as much as the straps would allow, and we got that one glorious moment of seeming weightlessness, before reaching a jerky stop and being raised back up for another drop."
It is…
rallain | June 9, 2009So, analysis of the movie Up is pretty popular in the blogosphere. Figure I might as well surf the popularity wave. So, I have a couple more questions.
The most important thing to estimate is the mass of the house. I am going to completely ignore the buoyancy of the house. I figure this will be insignificant next to the buoyancy needed. Anyway, let me go ahead and recap what has already been done on this in the blogosphere.
Wired Science - How Pixar's Up House Could Really Fly - from that post:
First, they calculated (seemingly correct) that the buoyancy of helium is 0.067 pounds per…
rallain | June 5, 2009Have you seen a cooler merrry-go-round than this?
Wow. A two-level huge merry-go-round with climbing ropes and everything. I didn't think you could have something like this in today's era of lawsuits. Man, the kids love this thing.
rallain | June 5, 2009In this WEEK in TECH episode 197 there was a pretty good discussion about education and the university system. In case you are not familiar with TWiT, it is a tech-based podcast with Leo Laporte (from the old Screen Savers show). If you want to listen to their discussion, it starts about half-way through the podcast. Here is what I find interesting - these are mostly tech-oriented people (there was one person in education) but they can clearly see some of the problems with the educational system. I think the following quote sums up their ideas pretty well (can't recall which twit said it…
rallain | June 3, 2009I haven't seen the Pixar Movie "Up" yet, so don't spoil it for me. I have, however, seen the trailer. In my usual fashion, I have to find something to complain about. There is this scene where the old man releases balloons out of the house.
What is wrong with this scene? Also, would that be enough balloons to make the house float? Here is a shot of the balloons coming out of the house.
Ok, I was already wrong. The first time I saw this trailer I thought the balloons were stored in his house. After re-watching in slow motion, it seems the balloons were maybe in the back yard held down…
rallain | June 1, 2009So, there is this Science Blogging Award from 3 QuarksDaily. Of course I nominated one of my own post - The Physics of Fantastic Contraption. The first stage of the competition lets readers vote for their favorite blog post. This seems sort of like a popularity contest. Then the top votes will be judged and a winner determined. The biggest problem I see is that there is a wide variety of posts, from physics to biology to medicine. It is kind of like voting for the best food with bananas and steak in there for the voting. Sometimes, you just need a banana.
Anyway, in looking at this…
rallain | June 1, 2009Notice how much I like the word "stuff". It really is a very useful word. I wonder if I did a wordle for this whole blog, would "stuff" be the biggest?
Anyway, I have been thinking about this popular Chronicle of Higher Education article Will Higher Education be the Next Bubble to Burst?. The basic argument the article makes is that higher education (especially private schools) are too expensive. It also talks about online universities such as Phoenix online and how they are becoming more popular. In all this "bursting bubble" discussion, there is an extremely important question:
What is…
rallain | May 29, 2009My brother found this, but he is too afraid of the internet to post something in the comments on my previous post about acceleration and the iphone. It turns out that this too awesome to just be in a comment. It deserves its own note.
Anyway, I was looking for acceleration data from the iPhone and this guy put one in his model rocket.
iPhone Rocket Launch and Interview (from MobileOrchard.com) from Mobile Orchard on Vimeo.
Here is some more detail (with graphs!) about the iPhone model rocket.
rallain | May 29, 2009Here is another one from a great podcast - Buzz Out Loud. I totally can't remember which episode it was, I listened to a several in a row mowing the lawn and doing outside type work. Anyway, the discuss was along the lines of:
Could an iphone tell if your parachute didn't open with its accelerometer?
The first and simplest answer would be "no". When you are skydiving, you quickly reach terminal velocity such that you are no longer accelerating. Maybe the built in GPS could use elevation data, but it seems like that is rarely used (and not very accurate). There is perhaps a way that work…
rallain | May 25, 2009When I was talking about balancing a stick, I mentioned the moment of inertia. Moment of inertia is different than mass, but I like to call it the "rotational mass". What does mass do? Things with larger mass are more difficult to change their motion (translational motion). A similar thing is true for the "rotational mass". Things with larger rotational mass are more difficult to change rotational motion. Here is the demo.
Demo for Moment of Inertia from Rhett Allain on Vimeo.
Why do I like this demo? First, it uses ordinary things. I consider juice boxes to be pretty ordinary.…
rallain | May 25, 2009I was wondering around the blogosphere and read some stuff about introductory physics labs. In particular, I was looking at ZapperZ's Revamping Introductory Physics and Dr. Pion's Objectives for a Lab. Both of these are good posts. Here I thought I would add make take on this subject as I am picking the labs I will use for the summer session of introductory (algebra-based) physics labs.
When I first started teaching this lab, my goals for the course were a lot like Dr. Pions. Namely, I would like the students to improve in the following areas:
Critical thinking
Writing and communication…
rallain | May 21, 2009I made a gamble and my gamble failed. It really wasn't my fault. In the preview, they showed this huge barrel thing dropping on a see saw. It looked something like this: (I could search for 30 minutes for a picture of this online, or just draw it)
At first glance, this looked JUST like that video of the pile driver shooting the skydiver up in the air. You can see how I would make that mistake. To make up for my mistake, I will give a very simple analysis of the see saw myth. The basic idea is that something comes down, hits the see saw and sends the other thing flying up. If I assume…
rallain | May 19, 2009Some of the other blog sites have talked about physics vs. chemistry. It seems this started with The experimental Error blog. Tom at Swans on Tea added a very excellent point to the discussion and the discussion continues at Uncertain Principles.
So, here is my take on the subject. Physics essentially deals with the fundamental stuff. You know, Maxwell's equations, the four forces, the particles, quantum mechanics. Chemistry is the study of substances and their interactions. First, let me attack chemistry. Here are some things I don't like:
Photo electron. What is a photo electron?…