Dot Physics

Archives for May, 2009

iPhone in a rocket

My 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…

Here 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…

Moment of Inertia Demo

When 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…

What makes a good lab?

I 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…

I 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…

Some 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…

Another electric motorcycle post. (Here is the post on the wind-recharged drag racing motorcycle) This new one is a solar powered motorcycle. The site claims that the bike can go 50 miles on a full charge (from Gas2.org). This is easily possible, but how long would it take to charge with normal solar panels? Here…

I think the Mythbusters have a wonderful opportunity for educational outreach. Take this week’s episode. One myth was to see if arrows fired from a moving horse penetrated more than arrows fired from a standing position. They first did this with real horses, but they said the data was not convincing. I am pretty sure…

Last night was Wednesday, so of course I watched Mythbusters. You never know when a good blogging opportunity will come up. I could talk about the kinetic energy of arrows, but instead let me talk about their episode for next week. I only caught a glimpse of it in the preview. It looks like they…

Maybe you have seen this trick. Basically, you hold by supporting it with two fingers from the bottom. You then move your hand around to keep it balanced while the stick is vertical. It is really not as hard as it looks. Also, there are two things that can make your job easier. Use a…