measurement

Dot Physics

Category archives for measurement

Variation in throwing a ball

I might as well make a new tag called “basketball throws” because I can’t stop with the analysis of these crazy basketball shots. Watch – in the end someone is going to post a video about how all these were faked (and I have said there is no clear evidence they are fake). Oh, if…

Potentiometer for angle measurements

There is something I am working on that will need some type of angle sensor. I am going to use a potentiometer. First, who came up with that name? Isn’t this name the same as a voltmeter? Something is wrong with that name. How about we just call it a variable resistor or something like…

There are several free iPhone-iPod Touch apps that let you look at the acceleration of the device using the built in accelerometer. I was planning on reviewing some of these free apps, but I didn’t. When I started playing around with them, it was clear that I needed some way to make a constant acceleration.…

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…

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 their data. The important point is they…

Cool things the Greeks did in astronomy

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).…

Suppose I am working on a problem and I wish to calculate the density of something. I measure the mass to be *m* = 24.5 grams and the volume is *V* = 10 cm3. In this case the density would be: ![Sigfig 1](http://scienceblogs.com/dotphysics/wp-content/uploads/2008/09/sigfig-1.jpg) ALERT! ALERT! ALERT! This is not a test!!!! Something is drastically wrong!…