pendulum
grrlscientist | June 15, 2010tags: Foucault's Pendulum, physics, rotation, Pendulum, Jim LaBelle, Dartmouth University, wow, streaming video
This video features physics and astronomy professor Jim LaBelle, as he discusses the truly fascinating science behind a classic physics experiment, Foucault's pendulum, while seated next to Dartmouth University's pendulum in Fairchild Tower.
While scientists already knew that the Earth had a rotation, they had struggled to come up with a way of definitively proving this was so. In 1851, French scientist Leon Foucault gave a sensational demonstration in the Paris Pantheon proving…
esiegel | February 12, 2010However time may be measured at the Naval Observatory, the clock seems to tick slowly here when Congress is out of town. -Richard Corrigan
The following is the mostly true (but somewhat fictionalized) story of the first clocks in the Americas. In the 17th Century, the finest clockmakers in the world were Dutch, going back to the time of Christiaan Huygens.
Image: A Dutch Longcase clock, courtesy of The Museum of the Dutch Clock.
Huygens determined that if you allowed a pendulum to swing just a little bit, the period of its swing could be used to keep time to incredible accuracy. By the mid-…
rallain | December 9, 2009This is a requested post. Clearly, I do requests. The idea here is that I am going to give all the details needed to determine the equation of motion (and then model it) for a basic pendulum. Warning: this post is a little more advanced than my normal posts. There are some prerequisites. You need to understand derivatives. I will assume that you do. Here is a pendulum. (and this time I will stick to my variables)
Like I said before, this is a tricky problem unless I use some tricks. The problem is that the tension the string exerts on the mass changes. Here is my trick: think about a…
rallain | December 4, 2009This post has been sitting in my mind for quite some time. Really, it is about mechanics - not about pendulums. What is the goal in mechanics (classical mechanics, if you like)? Generally, it is to find out how something changes over time. If you could get an equation of motion, that would do it.
As Matt (Built on Facts) did a while ago, it can be shown that you can get the equation of motion for a mass on a spring with normal Newtonian mechanics or with Lagrangian mechanics. Let me summarize two different ways of looking at the motion of an object.
The Newtonian Way
Maybe that isn't the…