Variable Resistors in Beauty Products

This past weekend we had a Valentine's Day Banquet at my church to fundraise for a trip we're going on this coming summer. We had to get all dressed up and act like "professional" waitors and waitresses. Thus, before the banquet I turned on my hair straightener to straighten my hair before the dinner so it wouldn't be all frizzy. My mistake came in turning it on the highest heat possible and leaving it on my unmade bed. It burned right through my mattress!! In all this, I realized that my hair straightener has physics to it because it is a variable resistor! When I turned up the heat, I was actually shortening the length of the conductor which is probably located inside of the straightener. By shortening the length of the conductor, I am decreasing the resistance, allowing the electrons to flow easier and have a greater current. A greater current means that there is more power and as a result, more heat coming from the straightener which is why it burned through my mattress!!

Microphones

This past Sunday, my youth group led the worship service at my church. It was a lot of fun because it really brought us together as we prepared for it. Some of us sang, some of us were ushers, some of us signed, and one of the guys in my youth group did the sermon. Anyway, I sang as part of the praise team and (much to my dismay and reluctance) used a microphone. Since I greatly dislike using a microphone, I would always hold it down by my belly button rather than up by my mouth. However, because I did this, the sound people always had to put my microphone on SUPER high and loud in order to pick up my voice. As a result, every time I even came a little bit close to the monitor a loud shrill shreak would sound. I thought that there must be some kind of physics to a microphone in order for it to 1) be able to make that shrill sound and 2) amplify your voice, so I looked up exactly how a microphone works. A microphone gives out an electric signal every time it senses sound pressure variations from your voice. It is made out of a small coil attached to a diaphragm and this coil is free to move inside of a cylindrical magnet. Whenever sound comes into the microphone, the diaphragm vibrates which causes the coil to move up and down between the poles of the magnet and your voice is amplified! I think that the reason why the shrill sound was made every time I came close to the monitor is due to the electric signal that the microphone is constantly giving out. The microphone amplifies every sound that it picks up, including the sound of the monitor. However, the monitor gives off the sound that the mic amplifies. Therefore, there is like a conservation of sound and when you put the mic close to the monitor, they amplify the sounds the other gives off which leads to the shrill shreak. This picture is of one of my best friends Sarah who sang a duet with my youth pastor. She held the microphone correctly (as shown) and sounded awesome!

Happy Birthday Great Grandma!

Last night I went to my great grandma's 99th birthday party. It was so much fun because family that I had never met came from the mainland to celebrate with us. We also played a couple of super fun creative games that my uncle prepared for us. One of them reminded me of what we are learning in Physics right now. In this game, we had to pick one person from our table to be dressed up like a reindeer in the most unusual way. At the end, my great grandma would judge who was the best reindeer, and the person she picked, would win. In order to make the antlers, you had to stuff panty hose with balloons. The person who dressed up from our table was my sister. However, we did not use up our balloons the first time because we didn't think they would all fit. But after comparing her to the other "reindeer" we decided to put them all in...except we had the hardest time taking the nylon off her head because the nylon and balloons kept sticking to her hair! This is a result of the attraction that was occuring due to an imbalance of charge caused by friction. After rubbing all the different balloons and the nylon together, the balloons and nylon both had a charge because they either gained or lost electrons. When there is an imbalance, the object attempts to gain neutrality again by attatching to something neutral so share/gain back electrons. Since her hair was still neutral, when we tried to pull off the nylon, it was attracted to her extremely long hair which made it hard to take off.

PADDLING :)

This past weekend we had our second paddling race of the season. The race was about three miles long and we paddled through some crazy wind! But, we were successful and we came in third after Punahou and Kamehameha. After the race, I was looking at my paddle when I realized it had physics in it!! When you take a stroke through the water, the lever arm is the length of your arm and the rotation point is your shoulder. As you twist to take a stroke, you are creating a torque when you push down with your top hand. Therefore, if you have a longer arm, then your lever arm is longer and you can pull more water. This is probably why my coach always tells us to twist our bodies out as far as possible and to reach out as far as we can in order to maximize the lever arm. This comes in handy especially upwind when you want your boat to move forward against the wind.

Physics at Home

I was sitting at my dining room table eating my dinner and trying to think of what I could use in my journal. Feeling a gust of wind, I stood up to turn the fan off because it was so cold, windy and rainy. Looking at the fan reminded me of what we are learning in physics - the difference between rotational and circular motion. The fan has rotational motion because the axis is within the fan. However, if you were to place an object on the end of one of the fan wings, that object would have circular motion because it's axis would be the fan which is on the outside of the object. If I were to push one of the fan wings with the fan off, my finger would be the force (the torque) and the lever arm would be the distance from my finger to the axis from which the fan is rotating around. I thought that it was really cool how I could find physics in such a simple and often over looked object!

Football!

This weekend, as part of FCA I went to the UH vs. Idaho football game. It was surprisingly really interesting and fun! Since my family doesn't have a TV, I don't really ever watch football and so I didn't know what to expect; but with Coach Dom's help I understood more than I usually do. Anyway, as I was watching, I was reminded of the homework problem we did about the football players who got tackled. However, instead of just reading about it, I got to watch and see it in real life! A physics problem come to life! I was able to see an actual sticky collision and envision that the two football player's momentums were conserved throughout the tackle. As one football player ran into a second football player, the (initial velocity of the first football)(first football player's mass) + (the initial velocity of the second football player)(second football player's mass) = (first football player's mass + second football player's mass)(final velocity). This law could also be applied to when a football player caught a ball. If the football player is standing still, when he catches the ball, the final velocity of the ball + football player is from the initial velocity of the ball. In all, I thought it was really cool to be able to watch physics come to life and try to figure out all the different ways physics could be applied throughout the game.

Physics in Toys

This afternoon, I was at my friend's house because we were supposed to be working on a Psychology project. While there, I saw this toy in her room and it reminded me about what we are learning in Physics. This toy follows the law of conservation of energy because the first ball bearing starts off with all the energy of the system while all the other ball bearings are at rest. However, as the ball comes into contact with the ball next to it, it transfers some of its energy to the second ball. This pattern continues as the second ball comes into contact with the third ball, once again transfering some of its energy. As a result, when the last ball is hit, there is still the same amount of energy in the system from the beginning. Even though the first ball no longer holds the same amount of energy as it did in the beginning, the total amount of energy within the system of all five balls, is the same. No energy is lost, and no energy is gained. This picture that I took of the action shows this law taking place!