blog 11

So, I was pondering what I should write my blog about when I was driving home.  I couldn’t think of anything…when SUDDENLY my dad had to turn the lights on because it was getting dark! :o and then I thought about how we learned in class that if you turn the motor off, but keep the lights on, the battery will drain quickly.  However, if you run the motor and keep the lights on then the battery won’t die because of the induced current and voltage in the system.  Also, I thought about how my car has a battery (which provides voltage) but it has a motor too! The motor includes a magnet, and current (from the car battery) which in turn produces motion and helps the car move! When we pulled into our garage, I noticed this huge black machine next to our circuit breaker, aka A GENERATOR! :o The generator uses motion and a magnet to create current through a wire. ;) LOVE YA MRS. CHEN!

ALSO...NOTICE THE TRANSFORMER IN THE BACK? :)

Blog 10

So...last week we scrimmaged KAHUKU for water polo!  During warm up, all of us heard this loud rumbling noise.  Minutes later we saw a flash of lightning and then thunder following after it! :0 All the players were scared because we were in the pool and if lightning were to strike the pool it would probably kill us.  Water is a good conductor, so we'd be in huuuuuuge trouble!  In physics we learned a little about capacitors.  Capacitors are almost like batteries in that there is a voltage difference and lots of charge.  Lightning is almost like a capacitor because the charge on the ground and the charge in the clouds create a voltage difference. The lightning is like the explosion or reaction that occurs when you connect the two plates.  So, unfortunately our coaches made us stay in the pool and play even though there was lightning!  I was soooo scared! But at least we had fun and lightning did not strike the pool!

MY ELECTRIC METER! :O

I'm sad because our energy bill was expensive!!!

Blog 9

On Thursday night we had the Iolani Fair 2011 kick-off meeting!  Before the festivities began, our executive committee helped out with decorating the student center.  One of our jobs was to tie the balloons together and attach them to the tables.  We also got to play with some of the balloons ;D.  Scott kept trying to make people’s hair stand up by rubbing the balloon against their hair and pulling the balloon away.  Now, how on earth does this all relate to physics?!? Well, in physics we’ve been learning about charge and static electricity.  When Scott rubbed the balloon against my head, he was creating a charge by friction.  Also, when he tried to stick the balloon to someone, only the rubbed side would stick because rubber is an insulator and does not conduct electricity well.  Due to this trait, the electrons remained concentrated on one side of the balloon.

Blog 8

Today as I stared into the computer contemplating on what I should write my physics blog about…I heard the garage door open as my mom pulled into the driveway.  Oh my goodness! I thought, CARS ILLUSTRATE ROTATIONAL DYNAMICS!  The wheels of a car rotate, exhibiting rotational dynamics qualities.  In physics we learned that rotational inertia is equal to the mass times radius squared.  Because my mom’s van has a huge mass, it has a very high rotational inertia which means that it is harder to start and stop rotating.  I notice this a lot when I drive because my dad has a very small Rav4, as opposed to my mom’s Sienna.  When I drive my dad’s car, I don’t have to step on the breaks as hard as I do in my mom’s because the rav 4 is lighter and therefore has less rotational inertia, and is easier to stop.  Cars do not only have regular kinetic energy causing them to move, but rotational inertia as well! (Because the wheels are rotating AND moving forward)! Wooohoooo!    

blog 7

Today I was EXTREMELY bored….so I was lying around thinking, WHAT ON EARTH SHOULD I DO MY PHYSICS BLOG ON? Well, while I was wandering around my house I found some little hand sanitizers with rubber cases around them so that you can attach them to your bag.  I decided to start spinning the sanitizers around in circles because I had nothing better to do.  To my amazement, I realized that I was witnessing circular motion right in front of my eyes!  In physics we learned that centripetal acceleration is equal to the velocity squared divided by radius.  Because the hand sanitizer holder thing has such a small radius, it probably has a very large linear acceleration.  Even if the sanitizer were travelling at constant velocity, it would be accelerating because it is changing direction.  We also learned that centripetal force is equal to the mass times the centripetal acceleration.  The sanitizer has a small mass so it definitely will not have as much centripetal force as a ball.  Yay for physics! J

blog 6

This weekend I went with my older brother and his family to the ‘Iolani v. Kaimuki state football game.  In physics we learned about impulse and momentum.  We learned that momentum equals mass times velocity.  When the football is thrown, it has a lot of momentum because it has a large velocity.  We also learned that impulse is equal to the change in momentum or force times time.  When receivers, such as Josiah, try to catch the ball, they try to have “soft hands” and increase the amount of time it takes to catch the ball so that they can reduce the amount of force exerted on them by the ball.  Also, when our awesome defense tackles the other team, they tend to have a larger momentum than the other players.  When this happens there is usually a stick collision and the defensive player will force the offensive player into the ground or in the other direction.  Go Raiders!