So I was reserving my last blog post for my momentum video I made last year. Unfortunately I couldn't find it last night. I went to Mr. Powlin today to get the video but it wouldn’t upload to the site, or to my email or Google drive for some reason. I’ll try to find the video again tonight, but if I can’t just picture me getting shot bare skin with an airsoft gun.
I figured I would finish my blog posts with a reflection of how physics went this year. At the beginning of the year, Mr. Fullerton introduced us to integrals. I had absolutely no idea what how to do them since we hadn’t covered it in math yet. Fortunately by the time they finally came up on a test, we had gotten to them and calc and I finally understood them. Overall the calculus included in the course was fairly basic and wasn’t very hard.
The independent units were definitely something new for me. I enjoyed them because I was able to work at my own pace. They forced us to learn how to learn the material ourselves without a teacher spoon feeding it to us; I think this will be beneficial to us all next year in college. The only thing I didn’t like was that the independent units required more work outside of class than our regular units. Fortunately I never had too much of a problem getting it all done because I spaced the work out.
Overall I found the course pleasantly challenging. The course load was never unbearable as long as you didn’t wait till the last day to complete webassigns and independent units!
I found an interesting article about how nuclear fallout has aided in studies on brain development. Nuclear fallout introduced small amounts of carbon 14 into our atmosphere. When our cells divide, they incorporate carbon from the environment. So the carbon 14 released from nuclear bombs eventually makes it way into the human body. This means that carbon 14 can be used to measure the age of cells. A team at the Karolinska Institute used this to show that new neurons were produced in a small part of the hippocampus called the dentate gyrus. I guess nuclear fallout has some positive benefits in terms of research.
So I read something really interesting about a particle called the “Oh-My-God particle”. Detected on October 15th, 1991 the particle was a proton that was traveling at nearly the speed of light. In fact it was traveling at 99.99999999999999999999951% of the speed of light. The proton had the energy equivalent of a baseball traveling about 100 kilometers per hour (imagine getting hit in the head and knocked out by a particle too small to see). Even the particles produced in our particles accelerators don’t come close to the energy of this particle; the proton has 40 million times more energy than the highest energy proton produced in a particle accelerator. Particles like this one has been detected multiple times since, but physicists don’t really know where it came from or what accelerated it. Wikipedia said something about spinning super massive black holes and possibly dark matter being the cause, but it quickly got too complicated for me to follow. Anyways I found this really interesting so I thought I would share it!
Nuclear energy has been used since the 1950s. However all nuclear power plants have been fission reactors. Fission results from bombarding uranium or other large atoms with neutrons. The atom then breaks apart releasing energy and more neutrons leading to a chain reaction. Nuclear fusion however has never been used for energy. Fusion is when two light atomic nuclei fuse to form a heavier nucleus, vast amounts of energy is produced comes from binding energy due to the strong nuclear force. Fusion power would be the most efficient form of energy if it could be achieved. Deuterium (an isotope of hydrogen) would be the primary source of fuel and is abundant in the ocean and more easily assessable than fossil fuels. The only problem with using fusion as a power source is fusion requires a temperature of about 800 million kelvin. At these high temperatures, the atoms are stripped of there electrons and the positive nuclei breaks into plasma. The excess positive charge causes the fuel to repel from itself. Two approaches exist for confining the fuel for fusion once it reaches extreme temperatures, magnetic confinement and inertial confinement. Magnetic confinement is the more promising and developed approach. In would use a solenoid to cause particles to travel along magnetic field lines thus containing them. Fusion power is still a long way from being practical. However if it could be achieved, it would be the most efficient form of energy.
Since I’ve already done a blog on dark matter I thought why not do one on dark energy as well! Like dark matter, the existence of dark matter has yet to be proven. Despite this, dark energy is theorized to ‘exist’ in very large quantities. Current models have dark energy occupying 68.3% of the universe. So if we can’t prove dark energy exists why do physicists believe it exists? Well because it’s the only thing that would explain why the universe is accelerating. We know from red shift that the universe must not only be expanding but is also accelerating. Thus some sort of energy must be present for the universe to accelerate. The fact that we can’t prove dark energy has lead to problems in predicting the future of the universe. If all dark energy is eventually consumed, the gravitational force of matter could cause the big crunch where the universe collapses back onto itself. Or dark energy could end up eventually overpowering gravity and the strong nuclear forces, ripping atoms apart leading to the big rip. Or the force outwards eventually equals the gravitational force and the universe stops expanding but doesn’t contract.
Antimatter is a very strange concept in physics. Antimatter consists of anti particles that have the same size and mass as their corresponding ‘regular matter’ but opposite charge. For instance a positron is the size of an electron but contains a positive charge. The current theory for the universe, the Big Bang Theory, predicts that an equal amount of matter and anti matter were present at the beginning of the universe. But today, anti matter occupies a negligible amount of the universe’s composure. So physicists have been stumped as to where all the antimatter has gone. Probably the biggest issue with studying antimatter is the fact that antimatter tends to be destroyed and converted to energy a very short time after its creation, because if a particle and its corresponding anti particle collide, the two particles will annihilate and be converted to energy. This poses a problem to physicists as any anti matter created artificially or naturally will very quickly annihilate preventing physicists from studying them. Moments after the big bang, matter and anti-matter were continually colliding and annihilate and then reforming from the energy released. How the universe has become dominated by antimatter is one of science greatest unanswered questions. Antimatter tends to form nuclear decay of atoms, the antimatter then annihilates, producing gamma rays. This is how we know that portions of the universe aren’t ‘dominated’ by anti matter because large amounts of gamma rays would be produced where the matter and antimatter sections intersect.
So I figured I’d, write about why our water bottle rocket failed so miserably on arts fest. Our goal was to use parachutes that would cause our rocket to slowly descend to the ground. Instead of using just one, we figured using two would slow our rockets fall even more. In theory this would have worked fine, however when our rocket reached its maximum height and the nose cone fell off exposing the parachutes, instead of fully opening, the two chutes tangled together and didn’t fully open. The unopened parachutes did very little too slow the decent, causing the rocket to fall very quickly back to the ground. Perhaps sticking to one parachute, or attaching the string of the second parachute to the top of the other would have been a better plan.
Well, I thought of yet another aspect of swimming to analyze for my blogs posts!!! Sometimes at practice we use these bungee or stretch cords to work on resistance training. The premise is simple, strap one end around your self, and the around the block at the end of the lanes. The bungee cords act just like a spring in that F = -Kx, the further the displacement the larger the force. As you get closer and closer to the other end of the pool, the force pulling you back becomes larger and larger. This especially sucks when your coach is pulling on the other end, leaving you just enough slack to get really close to the wall but not enough for you to be able to finish!
It seems the search to prove the existence of the elusive Dark Matter might soon come to a close. A Minnesota mine, half a mile under ground, seems to have detected the existence of Dark Matter. For those of you who don't what Dark Matter is, I'll give a brief explanation. The ordinary matter that we can visibly see makes up an estimated 15.5% of the universe. Planets, Stars and pretty much everything else in space is made up of ordinary matter. However 84.5% of the universe's matter is estimated to be Dark Matter. Dark Matter differs from regular matter in the way it interacts or lack of it. Dark matter doesn't emit light or radiation or create a electrostatic or strong nuclear force. So how do we know it exits? Well it because dark matter still has gravitational effects on visible matter. My understanding is that galaxies form spirals because of gravitational effects between the matter in the Galaxy. However our calculations show there isn't enough mass in many of these galaxies to hold them together, therefore we believe that dark matter exists and holds galaxies together. Because dark matter doesn't interact much with regular matter, proving its existence is very difficult. Any ways using a super conductor cooled to 50 millikelvin physicists think they have detected dark matter.
Reiterating Dave's recent blog post, I thought I would review what this last quarter has been like. So this quarter covered the E&M portion of the Physics C course. My general opinion is that the jump from Physics B to Physics C was far easier for mechanics than the jump for E&M. From the first two exams I learned that I was horrendously bad at the E&M free responses. I also found while taking the test, I would realize that I didn't really understand the material as well as I thought. However it seems that with the last two units, I've done better. With the practice free responses, I actually was able to get the majority of the points for the problem where as before I was getting a dismal amount of points. The last two tests, I actually felt like I understood the material and wasn't as stressed during the test. Hopefully the rest of E&M goes like the 2nd half of this quarter and not the first half.
This is our second independent unit in a row, meaning we haven't had traditional class in a very long time. This one seems a bit more difficult then previous ones though. Unlike previous independent units, I don't remember much about magnetism from last year making it more difficult. Magnetism also employs more complicated math like cross products and calculus based equations then the other independent units. I found it hard to understand the textbook and the only thing that stands out from the lewin videos his obsession with the magnetic monopoles. I feel pretty burnt out at the moment so I'm very glad the break almost here. I'm not sure if I even remember half of the equations from the book so I'm not sure how well I'm going to do on the test. Hopefully I can make it through the test okay, and then I can relax over break.
I found the most amazing video of superconductor levitating from a magnetic field. You absolutely have to watch this video!!! So basically a sapphire is coated with yttrium barium copper oxide. When cooled to -301oF, the saphire becomes a superconductor. The superconductor experiences no electrical resistance. For some reason the magnetic fields aren't able to penetrate because the superconductor expels fields from the inside. This leads to something called quantum locking which holds the superconductor in place. This is a quantum mechanism so its a bit beyond our knowledge of physics to understand, but none the less, its really awesome!!!
Has your hand ever been so cold that it went numb? Well how about when it was 90o and you were outside in the sun, no, well this has happened to me before. Over the summer I worked part time at clover home leisure. Part of my job was to fill up propane tanks. Normally not a big deal, but sometimes we get massive propane tanks with purge valves. While filling, the purge valve forces the air out. When tank is done filling, the purge value starts spitting out massive amounts of propane. Propane stored in the tanks is very very cold to allow more gas to be stored. So I have to reach my hand into the cloud of propane gas and twist the purge valve shut as it is spitting out the ice cold propane(frost will literally form on the tank while I shut the value) . So one day a guy came in with 14 of these purge tanks. By the time I had finished filling the tanks my hand had been frozen and thawed and refrozen and rethawed far too many times. So my story kinda got away from me so I should probably relate this to physics. Thermodynamics was included in our physics class last year and as we learned PV=nRT. From this equation we get that n, the number of moles or amount of gas is inversely proportional to the temperature. If we want to put as much gas into the tank as possible we have three options, cool the gas down, make stronger tanks that can withstand more pressure, or alter the fabrics of the universe so that the gas constant R is a smaller value. Naturally cooling the gas is the most wildly used method (altho for my hand’s sake I’d prefer if we invested in the third option). Thus this is the reason why the propane gas is so cold when stored in a fuel tank.
The navy is developing a prototype for an Electromagnetic Rail Gun. The Rail Gun would be use massive magnetic fields to accelerate a projectile at over 5000 miles per hour. The projectiles would have so much kinetic energy that warheads would become unnecessary components to the projectile. The projectile would be able to devastate a bunker just by making impact with it, making explosives unnecessary. Clearly such a weapon would be extremely useful in a wartime situation.
The Mag lab near Tallahassee has created a 45 Tesla Magnet. This Magnet is 800,000 more powerful than the earth magnetic field. The Magnet was build by placing a coil of wire inside a coil of wire inside a coil of wire ... creating a massive magnetic field. The Magnet proved so strong that a camera crew lost half its recordings just by being in the same building as the magnet.
Have you ever wondered if physics would be applicable to your life? How can you make what you learned in physics useful? Well Physicist Dmitri Krioukov used physics to get out of paying a $400 traffic ticket. Dmitri Krioukov wrote a paper titled "The Proof of Innocence" to explain to the judge that his traffic violation for running a stop sign was the result of the officer suffering from an optical illusion. The end result, Mr Krioukov no longer has to pay the ticket!! This proves one of two things, knowing physics can prove your innocence, or if make up a bunch of complicated stuff, someone who isn’t proficient in that field will believe it!
Well i thought my last post was about the physics of pain pong(a painful variant of ping pong) was pretty crazy. Well a professor from Brigham Young University took it to a whole new extreme. Professor Harold Stokes used a cannon to launch a ping pong ball at himself at over 500 mile per hour. Now that's dedication to teaching!!!
So last night the swim team got together for some pizza and to hang out. Being highly intelligent teenagers, we decided to play some pain pong. For those of you who aren't familiar with pain pong, it is a variant of ping pong where everything you loose the point you turn around and your opponent smashes the ball with the paddle at your bare back. Naturally if your quite bad at ping pong(like me) the game can get very painful, but why? Well its because of physics, more specifically impulse!
The impulse or change in momentum is equal to the force applied multiplied by the time of the collision. In the case of ping pong ball hitting my back, the change in momentum is a constant. The force is inversely proportional to the time of the collision. Since the time it takes to stop the ball is quite short, it leads to a large applied force, thus the large welts on my back
Engineering researchers at the University of Michigan have crated a nanoscale coating that is super effective at repelling liquids. The major difference between this coating and other coating is that with other coatings, liquids with very low surface tensions such as oils, alcohols, and organic acids stick to the coating and eventually diffuse through the coating; however with this coating, even liquids with low surface tensions are repelled. After testing well over a 100 liquids, the team at Michigan University found only two liquids capable of penetrating the coating which were chlorofluorocarbons. The coating consists of between 95 to 99 % air pockets. This prevents the liquids from coming close to the solid surface thus reducing the intermolecular forces that would attract the liquid to the solid. The liquid droplets failing to interact with the solid retain a spherical shape and bounce right off the coating.
So at yesterdays practice my coach made us take out the lane lines and put them on the reel after practice. As we spin the reel, the reel becomes increasing difficult to spin because the additional mass of the lane lines.
I decided it would be a great blog post to find out how much the moment of inertia changes for the reel once all of the lane lines are put on. I’m going to make some rough estimates on the dimensions of the reel since I couldn’t find them online and I can’t go in and measure them right now. I’m going to assume the rod going through the middle of the reel is .1m in radius and the radius of the when the reel is full, the maximum radius of the lane lines to the rotating axis is .75m. Now the reel is really light and spins easily when empty so I’m going to just assume that the moment of inertia is zero initially. The moment of inertia of a Cylinder with a hole in the middle is (1/2)M(a2+b2) where a and b and the radiuses of the cylinder. The mass of each lane line is 33.1 kg and there are 7 lane lines for a total mass of about 232 kg. Therefore the moment of inertia is (1/2)(232)(.12+.752) or 66.4 kg*m2. No wonder my arms hurt so much after spinning the reel.
The physics of the Powertower. So as previously mentioned in another blog, on the Saturday practices we do stations. One of the stations is doing sprints with THE POWERTOWER. What’s a Powertower you ask? Well if you have ever been to the pool and seen those giant red buckets attached to the metal frame thingy, that’s the Powertower. I’ve included a picture because I’m guessing none of you know what I’m talking about.
Anyways we fill the buckets with water and a belt is hooked up to a pulley system so when we swim with the belt on, we lift the bucket. The station we do involves us sprinting 10.5 yards for time while pulling the weight of the bucket. We have a time range that we are supposed to be in and if we are under the range, we increase the weight.
So initially I wanted to try to calculate a reasonable power ratio for myself while on the Powertower station. Unfortunately I underestimated the complexity of doing this. Even if I neglect the fact that the string has mass, the pulley has mass and the pulley system has friction (the pulley system is fairly complex and probably has a fair amount of friction) I still wouldn’t be able calculate my power. I would need my acceleration off the wall and my drag force experienced at my max velocity. The acceleration I figured I could estimate, but I realized that I couldn’t accurately calculate my drag force which I needed to find the average force I applied during my swim.
Then I realized I could just calculate the power through the power tower alone which is far simpler and actually realistic to calculate. I swam 10.5 yards in 5.9 seconds while carrying 65 pounds. This is equivalent to 9.6 m and 289.13 newtons. Because of the pulley system the bucket doesn’t raise it self by 1 meter for each meter I swim forward. Instead swimming 9.6m only lifts the bucket .8m. The force used to lift the bucket is the weight of the bucket + mass*acceleration. Using kinematics, I calculate the acceleration to be .0459 m/s2 and thus the net force to be 1.36 Newtons. The total force is therefore 290.5. Since Power is Force * Distance / time, the Power ratio is 290.5 Newtons * .8 m / 5.9 seconds = 39.4 watts. Just to put this in perspective, a typical light bulb’s power ratio is around 60 watts (I think). Although my actual power rating would be much higher, the power through the power tower is just a small fraction of my power ratio.
The physics of hypothetically cheating at swim practice. During Saturday practices, our coach has us do stations. One of these stations involves sprinting with a parachute.
As you can see the parachute is quite small but despite this, it still creates a whole lot of drag. The parachute is very thin and creates a large pocket that water gets trapped into. As the parachute is pulled through the water, the water getting caught in the pocket creates drag. Now 100% hypothetically speaking if anyone were to be feeling lazy and tired at 7 am on Saturday and wanted to reduce how much work they have to put in, it is postulated, supposed, and imagined they could potentially hypothetically theoretically tie the parachute in a knot. Doing this prevent the parachute from opening up, minimizing its surface area catching water. The drag experienced would be just a fraction of the previous drag. Devin don’t tell Brian about this blog, OR ELSE!!!!
The physics of Swim Paddles. Some times at swim practice our coach makes us use these paddles.
These paddles typicality increase how far we go with each stroke while slowing down our stroke as it takes more force to pull. This because with the paddles, our hands have a greater surface area. When we pull our arms through the water, we pull more water behind us. Based on the law of conservation of momentum, if I catch and push more water at the same velocity backwards I will have a greater velocity forward. However pulling more water takes more force causing us to slow down our recovery part of the stroke to compensate for the extra work, so overall we swim at close to the same speed. After using the paddles, our arms and shoulders are always more sore. When we’re feeling lazy, we will grab the smaller paddles because its less work for us. Yah Physics
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