Dance Showcase (Last Blog!)

Wow, I can't believe that this is the last physics blog for the year! Well, on Friday, we had our spring dance showcase and I realized that a lot of physics concepts were involved. The dancers that did jumps and flips in the air all followed projectile motion and conserved energy as they gained and lost potential and kinetic energy. Our class had to chant and hit our ipus to produce sound waves. We hit our ipus on cushions in order to reduce the impulse of the ipus by increasing the time of contact with the ground so that our ipus wouldn't break. When we spun around in circular motion (with our extremely heavy skirts exerting a force of mg that is always always always downward), our skirts opened outwards because of the fictitious force. There were lots of stage lights that were different colors because they had different wavelengths and frequencies of electromagnetic spectrum. At the end of senior tribute, some seniors were blowing bubbles on stage and I started thinking about how refraction and thin film interference were creating those changing colors. So, there's no more dance for the rest of the year, and physics is going to be over after the ap exam tomorrow...how time flies!

Glasses

I was practically out of ideas for this (second to last?) blog when I realized that my blog topic was right in front of my eyes (literally). Ok, so it's a pretty boring topic, but it goes back to some concept we learned in the optics section. I'm nearsighted, so I wear my glasses (or contacts) to help me see things that are far away. My glasses have diverging lenses, which make objects appear smaller but clearer. The diverging lenses refract light so that the images appear at the retina instead of in front of the retina. People who are farsighted have glasses with converging lenses to make closer objects appear clearer. The converging lenses refract light rays in order to adjust the position of the image so that it appears at the retina instead of behind the retina. Well, I'm definitely going to be using my glasses until late at night everyday this week seeing as there are tests pretty much every day this week...good luck to everyone who's in ap phys, apush, pch, dance showcase, and other exam giving classes this week...

New Air Conditioner

This week we got a new air conditioner installed in our living room. Thanks to the thermodynamics of the air conditioner, our living room is a lot cooler now. The air conditioner uses an adiabatic process to make the air in the room cool without a net heat transfer in the system. The first law of thermodynamics states that Q=W+ΔU. Therefore, in an adiabatic process, since there is no net heat transfer, the work done by the system is equal to the opposite of the change in internal energy. Work is positive, so that means that work is done by the system on the gas. The gas is alternately expanded and contracted to reduce the temperature of the air in the room. Well, the air conditioner will definitely be useful seeing as summer is slowly approacing...which also means that ap exams and the end of this class are near! Only a few more weeks of physics!

Pearl Harbor and Family Fair

Wow, what a great long weekend! Pearl Harbor field trip, Family Fair, and an extra day off from school! And only 4 days of school this week! So at the Arizona Memorial at Pearl Harbor, I, along with many of the other ap physics students, were distracted by the thin film interference pattern on the surface of the water. There was a thin film of oil on top of the water because oil was leaking from the USS Arizona underneath the memorial. I could see the thin film interference pattern because light reflected off both the top and bottom of the thin oil film, creating regions of alternating constructive and destructive interference. The ripples in the water show harmonic wave motion probably created by a disturbance such as the wind/ rain (it was super cold-totally could have used a jacket) or the boats moving in other parts of the harbor. At Family Fair, I felt the imaginary outward force created by the circular motion of the Turbo Tubs. We turned the wheel really fast so that we could move at a high angular velocity. Thus, decreasing our equilibrium and feeling extremely dizzy afterwards... :P. This weekend was filled with a lot of physics and a lot of fun!

The Hiroshima Atomic Bomb

Since we've been learning about nuclear physics, I thought about the atomic bombs dropped on Japan at the end of World War II. When I went to the Hiroshima Peace Memorial over spring break last year, I could see the massive amount of destruction that was caused by the atomic bomb. The first picture is a part of the Hiroshima Peace Memorial, the second is a replica of a slight shadow of a person who was sitting on the steps when the bomb exploded, and the third is a picture of a watch that stopped at the exact time the bomb exploded. It is hard to believe that just one atomic bomb and some microscopic fission reactions can decimate an entire city. Fission occurs when an atom, such as Uranium-235, is bombarded with a neutron to separate the nucleus of the atom into two smaller atoms. Because the strong force attracting protons to each other is broken with the introduction of the neutron, a large amount of energy and more neutrons are released. The released neutrons start more fission reactions and the chain reactions continues, resulting in the massive amount of energy released by an atomic bomb or nuclear power plant. The dropping of the atomic bombs was a negative use of physics in history and hopefully will never be used again.

Waterpark

I went to my friend's birthday party at the waterpark and although I don't believe my friend sent it an invitation, physics definitely showed up! The fact that we were all pretty tanned and/ or sunburned afterwards proved that the ultra-violet part of the electromagnetic spectrum mitigated the practically futile efforts from our sunscreen. Many of the rides were basically slides of different shapes and forms. If gravity didn't exist, we would not accelerate down the slides and we wouldn't feel the thrill! On one particular ride, Raging River (shown above), there were many points at which we felt like the raft was going to fly off of the slide. However, the opposing force of gravity towards the center of the earth always kept us on the slide. We switched groups and I noticed that when we rode with the bigger guys, the raft was even closer to flying off of the slide. This is because the momentum was greater. Momentum=mv and the heavier guys added to the mass in the raft. Therefore, it took gravity longer to change the direction of the raft and we felt like we were going to continue flying off the slide. I guess it was a good thing that physics came otherwise this party would not have been as fun as it was.

Mirror, Mirror, on the Wall...Wait There's More Than One...

When I opened the bathroom cabinet, I realized that the mirror doors created multiple reflections like in one of our labs. When the door opens all the way like in the first picture, the two planar mirrors are perpendicular to each other and they create 3 images. An image is created each time light rays bounce off the object, hit a mirror, and then reflect into my eyes. The images in front of the mirror are real and the images on the opposite side of the mirror from me and the camera are virtual. The virtual images behind the mirrors are the same distance away from the mirrors as my finger is from the mirrors. The virtual images cannot be seen but I could see the real images if I held a piece of paper in the correct place in front of the mirror. When I opened two of the doors at the same time like in the second picture, I saw many, many images because there was an image everytime the object or an image of the object existed in front of a mirror.

A Spoon (Concave Mirror)

So when I was eating dinner, I looked into my spoon and realized that it was a concave mirror! Just like the one in the lab! When I held my spoon about an arm's length away I could see my face, but it was upside down. This is because the object, my face, was farther in front of the spoon than the focal length of the spoon. I tried to create an upright image by moving the spoon closer to my face and making the distance less than the focal length of the spoon. However, I blocked out the light by moving the spoon too close to my face and I could no longer see an image in the spoon. This is because you can only see an image in a mirror if light rays bounce off an object and hit your eyes. I tried using a smaller object, my finger, and I could see the inverted image of my finger turn into an upright image as I moved my finger closer to the spoon. The distance at which the inverted image of my finger turned into an upright image is the focal length of the spoon. Since the spoon has a reflective surface on both sides, the other side of the spoon is also a mirror. The other side is a convex mirror. This mirror also distorted the image of my face, but as opposed to the image in the concave mirror, the image of my face was still upright with a bigger nose and smaller objects around me.

The "Tsunami"

That was some tsunami...all of like 1 or 2 feet of it...but at least no one got hurt and Kiss Me, Kate still went on! The tsunami warnings were triggered because the 8.8 magnitude earthquake in Chile triggered some unusual patterns in the ocean. The reason why an earthquake thousands of miles away can affect us here in Hawaii is conservation of energy! The earthquake created a lot of kinetic energy which needs to be absorbed by something else when the earthquake stops because energy cannot be created or destroyed. The earthquake was the initial force that created the unusual waves and the tsunami scare on Saturday. The earthquake and the waves were examples of oscillations. There were both transverse and longitudinal waves involved because the particles moved both parallel and perpendicular to the direction of the waves. However, the particles do have net motion because an earthquake or tsunami would not create any damage if everything returned to its original spot. An estimated time of the tsunami arrival in Hawaii could have been predicted by using the equation for the speed of a wave: v=wavelength/ time, if the speed of the waves produced by the earthquake in Chile were known.

Tripping the Circuit Breaker

Because we recently studied circuits, I thought about the time when all the electricity in the living room went off while my dad and my brother were playing video games on the Xbox 360. My dad turned off the fan in the living room and then went in the garage to on some kind of switch. At the time, I didn't really understand what happened, but thanks to physics I do now. There were too many appliances running in the living room, so the current in the circuit was too high. The circuit breaker was tripped in order to prevent overheating or an electrical fire. My dad had to turn off an appliance in order to reduce the current and reset the circuit breaker in order for electricity to run in the living room again. The different switches in the box correlate with the different circuits running in each room of the house. The whole house must not be connected in series, otherwise electricity would only run if every outlet had a running appliance. However, the circuit breaker for a room must be connected in series with the outlets in the room in order for the tripped circuit breaker to shut off all the electricity in the room. Circuit breakers are good alternatives to fuses because fuses need to be replaced every time they are blown (as we discovered in the lab when we connected them in parallel...), but with circuit breakers, you can just turn the switch to restore the flow of electricity.

Porcupine Magnet/ Paper Clip Holder/ Paper Weight

I was thinking about what to write about for my next blog topic when I saw this little porcupine thing on my desk. It's pretty cute and I'm not quite sure whether it's meant to be a magnet, a paper clip holder, a paper weight, or all of the above, but it definitely involves physics! I started playing around with the paper clips and the magnetic porcupine and this resulted in the structure in the picture. I realized that it relates to the last chapter about electromagnetism. The paper clips gain a charge when in contact with the magnetic porcupine because the opposite charges attract. The charge is transferred to other adjacent paper clips, creating the structure above (which took a lot of patience...). The forces in this structure had to stay in equilibrium so that I could take the picture. The downward force of weight on the hanging paper clip must be equal to the magnetic force holding it up. Also, there are torque forces (rFsintheta) acting on part of the structure (where the paper clips are halfway overlapped). The torque forces in both directions must be equal for the system to maintain equilibrium.

Hairbrush

Over the years, I've realized that when I brush my hair, it gets "staticy" and won't stay flat for a while. Sometimes, the same thing happens at school when I am sitting in a chair with my hair against the back of my chair. This is because when I rub my hair against something like a hairbrush or a chair, each hair has the same charge and like charges repel. I used to get really annoyed when my hair would not stay flat. However, I found an ionic brush that reduces the static electric forces when I am brushing my hair. The ionic brush somehow maintains the balance of opposite charges in my hair so that hairs of opposite charges attract each other and my hair stays flat. Brushing long hair can be a pain sometimes, especially if it's really tangled, because you have to exert more force to undo the knots.

Iphone and Earbuds

Sadly, my earbuds died...but I got to buy new ones-yay! When my earbuds died and I couldn't hear my music, I realized that this was because of physics. The battery in my iphone generates electricity to play the music and the electricity flows through the wires connecting the iphone and earbuds. Music plays through the earbuds (or is supposed to) because the electricity is converted into sound waves before traveling from the earbuds to my ears. Because electricity travels in a closed path, any break in the circuit (ie: disconnecting the earbuds or broken wires) will prevent the electricity from flowing and no music will be played. Since my current earbuds are new, all the wiring is intact and the circuit is closed when I plug my earbuds into my iphone. The closed circuit allows the electricity to flow and I can hear my music. I like my new earbuds :).

Marshmallows, M&Ms, and More

Today was a fairly nice and sunny day, so I was hanging out at the beach. My friend threw me some marshmallows and m&ms and I tried to catch them in my mouth. However, I was quite unsuccessful and the marshmallows and m&ms kept on bouncing off of my teeth or my tongue. I realized that I was failing because I wasn't using my physics knowledge. Because impulse=force x elapsed time, increasing the time of impact decreases the force of the impact. Therefore, I was more successful when i tilted my head back as I was catching the marshmallows and m&ms. It also helped when my friend threw the marshmallows and m&ms in a projectile motion with a large angle so that I had more time to make the catch. Also, when I was in the ocean, I was extremely cold because the heat from my body was moving to the colder water with a lower temperature.

Popcorn!

Yay! So I get to write a blog on my favorite food! (And I'm going to assume it's one of Doc's favorite foods too considering the constant supply of popcorn in the physics room) This afternoon, I started to pop a bag of good ol' microwave popcorn, but then I realized that I was about to witness physics! So, I ran to get my camera to take a picture of the unpopped bag of popcorn. When I stopped the microwave and opened the door to take a picture, I let heat out of the microwave because heat travels to the area of lower temperature. I closed the microwave door and after the popcorn was done, it had expanded to a volume much larger than the originally flat bag with oil and kernels. This was because of Charles's law: Vi/Ti=Vf/Tf. The microwave increased the temperature of the popcorn kernels, so they popped and increased the volume of the bag. Charles's law can be applied because the pressure and moles of gas in the bag were pretty much constant.

Personal Response to Thomas Friedman’s Hot, Flat, and Crowded

I read Thomas Friedman’s Hot, Flat, and Crowded over this winter break. It was somewhat interesting, but I found myself quite bored when my brain was getting overloaded with more information, facts, and figures than any sane person could possibly want to know. The beginning went by slowly (taking econ would have been helpful in understanding the first chapter), but as I read more of the book, I understood Friedman’s ideas more and the book seemed more relevant to my life.

The title refers to three issues in our world today. The world is becoming hot due to global warming, flat due to equality of economic opportunities across the globe, and crowded due the increasing human population across the globe. Our world has become this way because of “overconsuming, overbuilding, overborrowing, and overlending.” The current recession and global warming are related because both are results of carelessness and greed for money. The hot, flat, and crowded state of our world has also caused five more problems: increasing demand for energy/ resources, petrodictatorship, climate change, energy poverty, and biodiversity loss.

America has slowly slipped away into laziness in the area of innovation after losing Russia as a competitor. We have lost our long term thinking and replaced it with short term thinking and unsustainable ways. In order for future generations to survive, we have to stop wasting energy and materials and cradle to cradle new products. I also think that America has to wake up in innovations and pave the way like a city on a hill in the area of green technology.

Although Friedman’s Plan A code green idea does not seem feasible yet, it does sound cool and I think that it is something to strive for. He says that because everything on Earth is connected somehow, we need a whole new green system to run the world. His plan involves using clean electrons, increasing energy efficiency, slowing population growth, conserving, and adapting to inevitable climate change. I agree with Friedman’s idea of having a million Noahs, not just one, because we can’t just wait for someone else to do something miraculous; everyone has to be a part of this green effort in order for it to work.

I’ve heard about global warming before, but I realized that I’ve had that IBG/ YBG mindset all this time. Since the world doesn’t look like one of those 2012 or The Day After Tomorrow apocalyptic movies yet, I thought that global warming would take place very far in the future. However, after reading this book I have realized that global warming is a huge problem. In fact, as I was watching some New Years fireworks, it made me shudder to think of all the tons of CO₂ being sent into the atmosphere around the globe. People talk about being green, but all those fireworks made me realize that like Friedman says we’re having a green party now, not a revolution, because people are not taking enough action. Also, I think the BANANA republic idea is very true because people don’t mind the idea of a green party, but no one wants to seriously make the effort to do something to solve the problem or even be inconvenienced by a green project. We really do need to be the “re-generation” to build a new, greener planet.