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Once somebody asked me what I felt was more important: art or science. At the time I instinctively replied science, but upon further inspection I think that might have been a bias. I know a lot of people who don't want anything to do with science, and would much rather spend time expressing themselves in new and interesting ways. There's nothing wrong with either I suppose, but now that I'm getting older it might be good that I make a judgement call. I certainly still believe in stimulating progress as much as possible. But then again, who's to say that art isn't progress. Maybe it's a progress of the mind, the practice of developing new ideas and the cultivation of outside the box thinking. I think we can all agree, no matter who you are, that you need to be inventive to create progress. Isn't that the whole point? So then which is more important, cultural or mathematical progress? If you had to choose to keep one and destroy the other, which would you pick? I think that for me, the answer is still science. Of course we need free thinkers and inventors in order to really get anywhere in science, but if we focus on free thinking without getting results then what's the point? I don't think moral growth or maturity really mean much if you're not going anywhere anyway. I mean, what's the point of pondering what it means to be human if we'll never go out into the universe and find something that challenges that belief? Maybe I'm still locked into my logical thinking pattern, but I feel like there's a pretty good argument for seeking results over better ways to get results. Then again that goes against all the Disney movies I watched as a kid... Tell me what you think if you care, I'd love to get another perspective on why either art or science is necessary to human development.

Hotdog was right when she said that physics was completely nuts on the first day of physics. Physics can become overwhelming at anytime during your learning career in less than two seconds. Physics is a fine art and is shaped in many different ways. The cool thing about Physics is that it's used for practically everything; this is why physics is necessary for life! The first thing I would like to talk about are the VIR Tables. I really like VIR tables because once you get the hang of it you can calculate how much energy is running through your entire house. Another thing that is pretty interesting is that there are three different kinds of circuits, series, parallel, and mixed. All that can really help you get through this course is paying attention and asking questions. It also might help if you ask your teacher for more problems for practice. This shows dedication which is key in learning! Happy Studying!

If a random star were to appear in our skies, and you asked an astronomer how far away it was, they couldn't give you an immediate answer. One thing I always took for granted was how these scientists were able to map the night sky, give us a detailed perspective on what was out there in the final frontier. Some of these methods (like how to determine how far away a star is) can be somewhat interesting. Using the right math, many people could triangulate the position of an object, as long there are a few known variables and objects in the field of view. However, on Earth, to calculate how far away a star is, through distances spanning hundreds of light years, it is very difficult, because the angles which are being dealt with are very small, and hence prone to error. However, given a 6-month span, our orbit around the sun gives us a much better distance to do this calculation with. Knowing such things as the precise time, radius of orbit around the sun, and the positions of other stars in the sky, we can calculate relatively well star distances. However, this only really works up to 400 light years (thanks, HowStuffWorks), because, while the 150 million kilometer difference in our position is a lot, with a star 10 light years away (still fairly close), the difference in angle is still miniscule, clocking in at just a few hundred-thousandths of a degree. Which is to says, that while the distances we get aren't perfectly accurate, for what they're worth they are pretty dang good. There are different, more spectroscopic and more accurate methods of determining a star's distance, that rely on standard gathered data for stars that work at all distances. But before this data was collected, really the only way to gather this data was through triangulation. That, simply put, means that olden astronomers, those like Galileo, were the ones doing all this tricky math. Cool stuff.

Escape velocity, at the surface of the earth, is just about a whopping 11.2 km/s. This means that, to completely escape the force of earth's gravity, from the surface of the earth with the only outside for being gravity, you would need to be going this speed to escape (ignoring, of course, drag - drag forces at those speeds would rip a spaceship apart). So on my way to physics last friday I thought about how to reach those speeds, without the use of costly rocket fuel. One (although initially very costly solution) could be to have a giant underground tunnel, throughout the entire surface of the earth, that would accelerate an object over time using electromagnetism until it reaches those speeds. As long as the tube is in a vacuum, it is more than possible to do this. In order to keep an object in a circular orbit, we know that the centripetal acceleration must equal mv^2/r, and this net acceleration can only come from two other sources - gravity, at a constant 9.81 m/s^2, and the force generated by our electromagnetic coils. Assuming v is terminal velocity, E is the electromagnetic force, and r is approximately the radius of the earth, we get (11.2 * 10^3 m/s)^2/(6.371 * 10^6) = 9.81 + E. Solving for this, we can determine that E = 9.88 m/s^2, only a bit more than the acceleration due to gravity. If you could somehow construct this tunnel, it would be possible to bring objects up to speeds as high as this. Most of the time, for typical space missions, it wouldn't have to be quite so large anyways. The real issue is getting in out of the tunnel, and through the atmosphere. Going straight into the air at such speeds would destroy a fair chunk of the surrounding area, and most certainly the payload. You would have to create a giant vacuum tunnel through the atmosphere if you wanted this to work, which not only would look strange (it would be technically 'flat' - tangential to the point of release for the most part), but be very difficult to build. But in any case, it's wishful thinking.

Sometimes I like to sit back and pump some jams. Before the invention of all this modern technology such as speakers and cds and digital audio, such things just weren't possible. Music had to be performed. But with the invention of electrical speakers that all changing. People were able to finally jam out. The common speaker relies on the principles of electromagnetism. In the center is a magnet (attached to a speaker cone), surrounded by a coil. As the current through the coil fluctuates, the magnet and cone move, vibrating to reproduce the encoded sound. However, all things have inertia, so it can take time to reverse the momentum of the cone, creating a loss in audio quality in the event that the speaker cone is too heavy. Similarly, if the cone isn't stiff, it will delay its movement and creating quality losses that way as well. These losses are most noticeable with "harsher" waveforms (such as squarewave, which, as the name implies changes position very quickly at wave boundaries), or with more complex sounds, such as violin or saxophone. Because of these drawbacks good sound systems often have multiple speakers, all tuned to a different frequency. Subwoofers are typically larger because lower frequencies are less audible, and lower frequency waveforms are easier to reproduce in terms of speaker design. Tweeters are smaller for the opposite reasons - they need better accuracy because higher pitches involving larger shifts in momentum with respect to time, so they are typically smaller to achieve this. Also, because every material has a resonant frequency (where it will absorb a lot of energy), the materials in each are tailored to avoid this. Next time you're cruisin', bumpin' along to your favorite song, remember this. And invest in a better sound system.

In the past few years, the Dyson Air Multiplier has revolutionized the field of recreational air transportation. It's for this reason that I feel it warrants a blog post, all to itself. Lauded for a lack of (visible) fan blades, it is safer than the more common axial-style fan. The Man Behind the Magic But how is this trickery pulled off? Allow me to explain. The Dyson Air Multiplier does, in fact, have typical fan blades. But instead of being open to the air, they are hidden in the base of the fan, and air intake is through the little gratings along the circumference of the tube. That air is then "pumped" through the upper ring and exits the fan. But then why is it called an "air multiplier"? Dyson claims that the fan outputs 15 times the input air volume, and it does (or at least comes close). It does this as a result of Bernoulli's Principle, which states that faster moving air has a lower pressure. Because the air in the center of the ring is slower, and therefore higher pressure, it tends to get "dragged" along behind the small amount of air that is output, bringing more air into the mix. Conservation of energy still applies, so yes, the air does get decelerated during this process to account for that. It still does have a fan in the base, which can be noisy in getting the air up to an acceptable speed to "multiply" it. But it is a unique and interesting concept nonetheless, and a mark in the record books for "fan"-atics like me.

I was just looking around on the usual places and I found something that some of your students might be interested in. It is using ultrasonic standing waves to levitate objects.

Hi there. I'm a new Physics AP-C student, and I would like to tell you a little bit about myself. I'm an avid programmer/science enthusiast, and am looking towards entering a scientific or science-related field. I (as one may assume) like science and math, and more leisurely things like playing video games or disc golfing. Things of the sort. The reason I'm taking Physics AP-C this year is because I'm interested in learning more about physics and I want to solve more challenging problems using my physics knowledge. I enjoy calculus and I think it will be cool to see some of the applications of what I learn. As a result, I hope to not only hone my calculus knowledge but get some useful information on specific areas of physics and, in general, how to approach difficult, complex problems in an effort to solve them. I always enjoyed electricity and magnetism, and I'm looking forward to that and hopefully being able to dream up some cool uses for my new knowledge. However, no matter what we learn, I think I'll be excited just to know it. So I'm hoping to have fun!