24

this weekend, i caught a ride on teh bus to my track meet which was at kamehameha. while i was sitting down in the bus, i noticed couple things that were physics related stuff. for example, i noticed the usage of mirrors. there were mirrors arranged in a manner so that bus driver could see most of the things around him. another thing i noticed was the glass windows which acted like a mirror. while i took a glance at the reflected image on a window, i noticed that the image distance and object distance of the scenery were the same, which was pretty cool. also, i noticed that there were many convex mirrors so that people could see a lot of things around them. after learning how stuff works in physics, life became more fun, doc.

23

The "Mirage Mirror" is really two parabolic mirrors with identical shapes. One (mirror A (bottom)) lays face-up on the table while the other (mirror B (top)), which has a hole in its center, lays face-down on the first mirror. They are designed so that the focal point of one lies just at the vertex of the other when they are placed on top of one another. An object placed at the middle of the bottom mirror will be at the focal point of mirror on top. Light from the object reflects off of mirror B into parallel paths. This light shines on mirror A, reflects, and converges to the point fA. This light makes a real image at fA. If you look at this point, you'll see the object appear to hover at that point.

22

this weekend was very key doc. i had a track meet and wow, it was full of physics. take long jump for example, that thing is a great example for kinematic equations. a runner wants to get the greatest x velocity (speed youre running forward) and then get the maximum y acceleration/velocity (height). that's like projectile motion we learned except in the real life long jump there's wind speed, air resistance, what so ever. also, take a look at them spikes. whoever thought of using spikes must know a lot bout physics because they mustve known that more friction on your shoes makes you get the minimum energy loss through impact. another one is discuss throwing. instead of throwing it in a linear motion, they use rotational force because centripetal force and so on gives greater speed and energy to throw. the speed is the tangential speed which the discuss obtained through rotational dynamics. this is why i run track doc.

21

this week, i played drums for sr. luau and afterwards i wondered how drums worked again. last time, i was wondering about toms and snares and so on but now i started to wonder about cymbals. the drum set i used have 2 cymbal and a hi-hat which is kind of like a cymbal. one of the cymbal is called crash cymbal which is used to make a loud noise at the end of a song or the end of a fill. another cymbal is called ride cymbal which makes a high pitched sound and often used when the song is quiet and slow. hi-hat is used most often and it consists of two cymbal stacked like a pancake with a space inside (because cymbals arent flat, it has curved surface). What i wondered was, what makes these cymbals so different because none of them sounds the same. ride cymbal has the biggest surface area so when i crash it, it makes the dimmest sound. on the other hand, hi-hat though i never tried it, will most likely make the brightest sound when i crash it. but this doesnt explain why ride cymbal has the high pitched noise when i hit a different spot of the cymbal. we need to learn more physics to figure this out doc.

20

lately, i have been trying to learn how to play drums. it is quite difficult to learn but i still have joy in learning how. One day, it just happened to me and wondered, "hey, drums are perfect example to show what we have been learning this entire time!" First of all, the way drum stick bounces off the drums is the proof of newtons law and the laws of conservation of energy. the energy i put in (both potential and kinetic) to hit the drum is conserved (well not really but kind of). Because of friction, some energy must have turned into heat energy but the more energy i put in, the louder the sound becomes and faster the stick bounces back from the drum which explains this concept of cons. of energy. Also, the tension of the drum deteremines the pitch and frequency of the sound i make. The tighter drums (higher tension) give more higher pitched sound while loosened drums give off lower pitched noise. Not only i learned drums, i was able to review my physics knowledge, Doc!

19

this weekend i got static electricity hurting my finger while i was pushing my cart. well, it was partly because of my bad habit of dragging my feet as i walk. but anyways, i was walking, and then after walking around for a little while i got back to my shopping cart. when i tried to reach for it and touched the metal part of the handle, i got zapped. it hurt a little but not so much so i kept trying it over and over again until i noticed that someone was watching me do that. anyways, after a while, i began to take this in a scientific way so i can analyze how and what is going on. as i drag my feet, i collect all these charges and i have a concentrated electrostatic energy inside of me. when i touch the metal handle, the electric charges attract one another and thus making the electric energy. its something we just learned so i thought it was interesting doc.

18

this weekend, my friends and i were practicing for a presentation of a song we are going to do at senior luau. When my friend was playing guitar, i noticed that our physics knowledge could explain how guitar works. It is all about frequency and its relationship with length which we had been learning. as he slides his hand toward the bottom of the guitar, the pitch goes higher and higher because the frequency is greater due to the shortening of the length. after figuring that out, i began to experiment with guitar because i wanted to test it out in real life example. although i had a knowledge, i dont think i really examined a real life situation where that happens and how frequency could affect the pitch. So i examined and experimented and i was satisfied with the results. after examining it, i noticed how clever people were to invent things like this. I wonder if they knew the physics property when they made instruments.