hot afternoon

It was a hot sunday afternoon, so I decided to go sit down on the couch and watch some tv with the fan on.  My fan turns out to have an oscillating feature even though it's really old, so I punched in that button and sat down and relaxed.  The fan blew air in a fairly wide arc, spreading the cool it throughout much of the room at a very quick pace.  Soon I was relieved of the heat of the afternoon.  I realized that this has a lot to do with the physics we are learning because it is related to oscillation and wave motion.  The fan follows a certain pattern and always returns to the same spot in the same amount of time.  If I were to graph the displacement vs time graph it would look like a cos graph with a medium amplitude.  

fluid dynamics

This weekend I saw one of those inflatable bouncing castles.  It was very cool because it has a lot to do with what we've been studying in physics.  The machine pumps air through the castle so that kids can go and bounce on it.  I noticed that when one kid jumped up and landed, a kid next to him would feel the air beneath his feet pushing up against him.  This all has to do with the fluid mechanics that we have been studying.  Since air is considered a fluid, it fills up the entire container (the castle).  Since they want kids to be able to jump on the castle they need to have some place that some of the air can pass through, otherwise the pressure would build up and the castle would explode!  Anyways, after i finish physics homework, i'm going to relieve some stress there.

swimming!

This weekend my uncle, aunty, and two little cousins came from Seattle to visit us.  On Saturday we all went to go to the beach where we swam, built sandcastles, and ate lunch.  In the water I realized that, when fully submerged, I felt practically weightless, much like astronauts do in space.  Then I remember how many astronauts do underwater training in order to simulate the conditions of space.  When under water, you don't feel any forces pulling or pushing you in any direction, except for waves that come crashing over you.  Then I remembered all about how we're learning about gravity and orbits, and the effect of gravity from other planets.  This also relates to how the moon's gravity affects the tides of the ocean.  Interestingly, I didn't feel any force pulling me up towards the moon.  Perhaps because it was so small compared to my mass, or simply because the Earth's pull was much much stronger on me.  Either way, it was a very educational and very fun trip to the beach.  

Torque

Today my uncle came over and tried to fix our door handle.  While I was helping him, he asked me to hold one of the screws in place so he could turn it using a screwdriver.  This immediately made me think about the force required to turn the nut.  T=r x F.  This was not the only time this weekend that I thought about torque.  In tennis when you hit the ball, you don't want your racket to unintentionally turn on impact otherwise you will mishit it.  This depends a lot on the torque of the ball on the racket, and vice versa.