On March 11, 2011, a 9.0 Mw earthquake struck Japan and crippled the generators that cooled the nuclear fuel rods at Fukushima Daiichi. Nuclear reactors work by having some kind of fission of atoms such as U-235 into neutrons and daughter nucleii. Graphite rods within the sealed reactor absorb some of the released neutrons in order to control a possible chain reaction and regulate the rate at which energy is being released. Heat is usually created by this reaction, and water surrounding the rods steams and powers a turbine to generate electricity. The problem is that the radioactive metal can get extremely hot if its not properly being cooled, and in the case of the reactors at Fukushima Daiichi, they overheated. This is called a meltdown and can be dangerous if the radioactive substances break through the walls of the reactor and are released into the atmosphere. Reactors 1, 2, and 3 were rated a level 7 on the international nuclear event scale while reactor four received a level 3. This is because the first three reactors exploded from pressure and released radioactive substances into the air!
Today, my friend Stephanie Lum showed me her screen protector on her iPhone. I had never seen one like it before. It was reflective when the screen was off, thus serving as somwhat of a mirror. However, when the screen was turned on by pushing the lock button you could see through it clearly. The film gave the screen a slightly pink tint if looked at directly, but when i started moving the iPhone around, an entire rainbow of colors could be seen across the thin film. I immediately screamed PHYSICS!! THIN FILM INTERFERENCE!! What most likely happened was that there were three dfferent indeces of refraction. Air being 1.00, the film being intermediate, and the glass with the greatest most likely. When light from the fluorescent bulbs above also shined against the LCD screen of the iPhone, the white light refracts and different wavelengths of the light clearly show on the screen protector as distinct bands of color!! Phun times.
When my sister came back home from California for a month during Winter vacation, she proceeded to indulge herself in Hawaiian luxuries unavailable to her while living on the west coast. We both gorged ourselves with delicious food and went and played soccer in the park enjoying the beautiful weather. However, the one thing she had been waiting for was to get her tan back. While in California, her skin became very white because she wore long pants and sleeved shirts due to the colder climate. The problem was that there were many times where she simply could not find parking at the beach, or didnt have enough time to go there and tan for hours. Her solution was to tan indoors since we live on the 12th floor of a building in kaimuki with a large window in the family room. So she put a towel on the carpet and set up everything getting ready to tan, including dressing up for the beach! To her dismay, she wouldn’t get very much darker. Her skin showed very very little change in hue and she was quite upset. She explained that she could feel the heat of the sun and that it was exactly the same as lying on the beach. I didnt know what to say at the time, but now that im in AP physics B…….I know why! She probably forgot this lesson over the years and now i can explain it to her! Light waves from the sun actually contains visible light, infrared, and UV light. The heat we feel from the sun is from the infrared waves, which seems to bake our skin! However, the truly detrimental wavelengths are the UV light waves. They cause the actual tanning and can result in skin cancer if there is too much exposure! It is due to this danger that nearly every window has materials within that block out almost all UV light waves. This is why even though my sister could feel the heat from the sun, infrared waves dont result in tanning of the skin. Her skin only got a little darker because of the limited amount of UV allowed through our window! She wont be making this mistake anymore!! Thanks Mr.Heyler!
When I was a little boy, one of my favorite toys were the zapping magnets that would make a loud noise when thrown closely into the air. They were quite powerful, and would even retain their magnetic attraction through our dinner table! I remember one night, I went up to my sister who sat at her computer typing a paper (Iolani alumni, graduated from UC Berkely :)) and started to play around with the magnets when one of them hit the tower of the computer. I recall her getting really annoyed and irritated, trying to explain to a toddler that his magnet toys could mess up her computer and she could lose all of her papers! As always, i didnt understand at that time, and now that I’m in the wonderful AP Physics B class, it has been explained! Hard drives are where computers store their operating systems, programs, and data. What happens is a magnetic head moves over the surface of the harddrive and changes tiny magnetized regions called bits to say either 1 or 0. Magnets could potentially throw everything off by switching numbers and erasing certain parts. Although this may have been a problem with older computers, nowadays magnets aren’t really a threat. Modern harddrives are built to withstand magnetic forces from around the house or office. If you were looking for a magnet strong enough to affect a harddrive, it may typically only be found in laboratories or government offices!
Most power outlets in the US are standard 120V compared to in Europe and Asia where it is nearly double. However, in all areas, these power outlets are extremely dangerous sources of electricity and current that could lead to fatal injuries if used improperly. One instance of this is talking on a cellphone while it is charging. This poor guy suffered burns on his hand and all along his neck to his ear from electric shock. Apparently, there are often many faulty parts in mass produced (made in china…) mobile celphone products and if they were to overload, they could explode and shock the user with electricity current straight from the socket. So actually, this man was lucky to escape with his life after his cellphone exploded. Electric outlets are dangerous because there is a nearly infinite amount of current flowing through it and at a decently high voltage.
When I went to Ali’iolani Elementary school, there was a playground located in the middle of the campus. Every recess, us children would rush to to the playground and release the seemingly infinite amount of energy we had. One particularly memorable experience i had on the playground was discovering how to zap the other kids. I would slide down the plastic slide. As i was sliding down, i could hear the crackle of the friction between my clothes and the slide. After i got off, i would run to my friend and shake his hand or just tap his arm, and there would be a *pop!*. This discovery made me infamous and eventually i was sent to the principle. As i explained to her what i would do, he simply giggled, and let me go. All she told me was not to hurt the other kids! I couldn’t understand why i suddenly had the power of Zeus after going down a slide, but now after learning about static electricity, i know on a scientific level why this happens. When i slide down, friction between my body and the slide charges me, similar to charging a baloon by rubbing it against your hair. thus when i walked on the rubber flooring over to my class mate and touched his arm, the transfer of electric charges would give him a zappingfeeling and create a popping sound! I was quite abusive as a child…
Last weekend, my uncle bought a new Subaru STI hatchback sports car. He was really eager to test out its abilities and asked me if i wanted to take a spin in it. Being a car enthusiast even before i could pronounce the word car, i was excited and told him id love to ride in his new sports car. This model of the Subaru contains an IHI VF52 turbocharger, which pushes the cars horsepower close to 400 hp. So we went out at around 10:00 pm on the H1 and drove around until we found a stretch of road that seemed open. When he saw that the coast was clear, he accelerated the car to feel the turbo boost. After doing this for quite a while, we began to smell something similar to burning plastic fumes, so he drove us back to his house and popped open the hood. We could immediately see that there were small and faint wisps of smoking rising through the thremal-block cover ontop of the turbo charger. Immediately, he unlocked the cover, and opened it to find the turbo red hot, as was the interiors of the engine. This reminded me of our lesson on Carnot’s heat engine and how a perfectly efficient engine could never exist. This is because the cold reservoir would have to be at asolute zero or the infinitely hot. In the Subaru’s case, the heat rising from the turbo is the waste heat that also provided for work. This heat is also entropy and random wasted energy that is emmited.
Whenever i break out the italian style dressing for my salad, im forced to shake the bottle vigorously for a number of seconds in order to ensure the dressing comes out nice and even. If it isn’t shaken adequately/properly, the dressing comes out nasty and seperated! Now that I learned about buoyant forces in physics, i know why my Italian salad dressing always seperates and needs to be agitated! The equation for buoyant force is Fb=PflVG, or density of fluid multiplied by volume and gravity. This equation yields the force of the displaced fluid in newtons against an object. An object sinks in a fluid if its density is less than the fluid its in! This is why the herb mixture sinks below the oil in the italian salada dressing. The density of oil is less than the herbal mixture, and thus it floats above it! Also, you can calculate the percentage of the object that will float above the fluid by dividing the density of the object by the density of the fluid. If the density of the object is greater, then it’ll be over 100% so itll sink. If it is less than 100%, then the percentage is how much it is above the fluid. NOW I UNDERSTAND WHY MY SALAD DRESSING IS SO WEIRD!
A couple of years ago, I went to visit my sister who lives in California. She graduated from ‘Iolani and went to UC Berkeley. She had a friend who had a race car and often took it down to the famous Laguna Seca Raceway in Monterey. Since I have always been a fan of cars and racing, he took my sister and i with him one time and luckily enough we happened upon real Le mans racers practicing on the legendary race track. These supercars flew at blistering speeds around tight bends and on the straightaways. Since i had not taken physics back then, I didnt really understand why the cars didnt go crashing into the walls and instead stuck to the turns so well. Now that I have learned about banked turns and circuar motion, I can apply my knowledge to understand how the race track works. Pictured above is the most famous of all of Laguna Seca’s hazardous turns; the “Corkscrew.” It is a steep drop with an “s” shaped turn that is banked evenly . As the race car enters the corkscrew by turning left, there is a slight bank, and as he drives further down into the right turn, there is pretty heavy banking. The force of friction on the road pulls the car into the center of the circle or turn, and thus gives the race car the ability to drive at freeway speeds down such a dangerous series of turns. The force of gravity also helps to pull the car into the center of the turn. Because the force of friction and gravity both help to pull the car to the center, they are called centripetal forces, or center seeking forces. The car’s inertia is always in a straight forward direction, but the centripetal force allows for the turning.
This weekend I went skateboarding with my friends Tai and Quinn on government property in order to have an awesome blog post and ensure an A. Skateboarding perfectly models momentum and movement because the place we skated at was very smooth and the wheels provide for a ride thats considerably close to being frictionless. Momentum, or p, can be described as the product of mass and velocity. The mass would remain constant because it would be the combined mass of the skateboard and I. The velocity however would be the variable. If i did not propel myself, i would eventually slow to a stop due to friction. Therefore, momentum changes with my leg pushing backwards to increase my velocity, and also changes when i slow down from friction. This change in friction can be calculated as impulse, or j, which is the product of force and change in time. impulse is also, delta p or change in momentum, thus they have the same units. So whenever i push on the ground with my foot to accelerate, my impulse increases, and when i slow down from standing still on the skateboard, I have negative impulse. When i am completely motionless on the skateboard, momentum is equal to zero, and therefore so is impulse.
edwinli227 