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Rshadler

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  1. Rshadler

    Blog Post #1

    By Rshadler,

    Hello! If you are reading this then you've found your way to my physics blog.



    To be honest, I did not expect to be doing this sort of a thing when I chose to take AP Physics C, but I'm not complaining either.
    A little about me first then. I believe I am fairly strong intellectually, particularly with math and science because I find it much more interesting than most other subjects. I hoping that AP Physics C will help me improve my calculus skills though, as the concepts are new to me. Having taken previous physics courses (what used be known as AP Physics C I took great interest in optics. I'm hoping to study Imaging Science in college, which is essentially the study of an imaging captured and perceived.

    So now why AP Physics C? Well, having interned at the Rochester Institute of Technology's College of Imaging Science, I learned that physics and calculus are quite important for an Imaging Science major. For that purpose, I choose to take AP Physics C, hoping to improve my knowledge of physics and prepare myself for college. I'm really looking forward to the lab experience and I'm actually excited that we have such a small class size because we have all already started helping and working with one another on classwork and labs. I'm still a little anxious about having to teach myself individually without the help a lot of guided class lectures but I also think it will be a great lesson to learn as I move towards college.

    I'd like to explain real quick what my blog is all about. Each of my posts is going to be based on an episode of Doctor Who. Haven't watched it? Here's a quick synopsis: its TV show about an time-travelling alien and his human companions and it recently had its 50th anniversary special. There's a lot of physics concepts that are ignored or worked around on the show so that's what I'm going to talk about. Each post will center around an episode, either a new one or a past one.



    And let's hope I can come up some more interesting post titles...sorry about that. Oh and all the images used here are from Doctor Who.

    Now...


  2. Rshadler
    A quick reiteration for anyone reading this that doesn't know what Doctor Who is: it's basically a show about a time-travelling alien and his human companions (you really should watch if you haven't). My weekly blog posts are going to be about the physics of Doctor Who from episodes past and present. I'm not going to get into the physics of time travel just yet though.
    I'm going to start with this:



    So there is an average, run of the mill human being floating in space with nothing but her pajamas on. Except, physically that doesn't make any sense. In order for Amy (that's her name by way, and the man holding her foot is the Doctor- the alien who time travels) to be able to live in space there would need to an atmosphere, so that she had the oxygen necessary to breath, and there isn't one in space. Space is a vacuum which means there is no atmosphere and therefore Amy would not have air to breath and would be unable to live while floating in space like she is and yet she does. How is this explained then? On the show, the Doctor tells Amy that the T.A.R.D.I.S. (his time machine, the blue box) created an atmospheric shell, effectively creating a bubble around itself so that living beings can breath and thus Amy could breath. I don't believe this something that it is possible by today's standards but then again this show isn't always set in today's time. This would be an example of the writer cleverly working around the fact that 75% of what happens on the show defies at least some physics concept. Ok, that would be it for now, but I'm working more so stay tuned!
  3. Rshadler
    Ok, so this the best I can find, go to about 2:00 and watch that little bit (where he is working on the rocket).

    https://www.youtube.com/watch?v=E9A0Dev7DQw

    I thought this could be a fun one to use to talk about rockets! Ok, I guess I'm more talking about a question I got wrong on a recent test. So the question was why do objects in a rocket that is in orbit around Earth appear weightless? I've done some research and I'm ready to give it another try.

    As it turns out, for a rocket or space station in orbit around Earth, there is an acceleration downward. So technically, the space ship is falling toward Earth as it remains in orbit. Since the the person typically has the same acceleration as the space ship and the space is also moving around the Earth, they feel weightless.

    Moving on, some basic rocket physics! A rocket obtains thrust through the idea of action and reaction (Newton's third law). As the rocket propellant ignites, it experiences a very large acceleration and leaves the back of the rocket (as exhaust) at a very high velocity. This backwards acceleration of the exhaust exerts a force on the rocket that pushes it in the opposite direction, causing the rocket to accelerate forward.



    Yay! Okay so that's about it! Thanks for reading!
  4. Rshadler
    From this episode I get to talk about something pretty neat: solar flares. Yes, the plot of this episode revolves around a magical forest covering the Earth over night in order to save it from a massive solar flare. Confused yet?



    Solar flares are massive explosions on the surface of the Sun that release a significant amount of energy in multiple forms at once. A solar flare occurs when magnetic energy that has built up in the solar atmosphere is suddenly released. So, one of the most important types is the release of electro-magnetic energy. So while it looks like a huge spike of fire is leaving the sun, by the time a solar flare reaches Earth the most important issue to watch for is the impact of the electro-magnetic energy. What is really cool though is that Earth actually has its own protection- an actual force field that dampens or repels the effects of solar flares.



    It ends up looking something like this. Earth's atmosphere and magnetic field actually help protect from the impact of solar flares. These are called Van Allen belts- they are radiation belts that act as part of Earth's magnetic field- and when the stream of high energy particles meet Earth's magnetic field they are push along these belts towards the north and south poles. Sometimes these flares can cause geomagnetic storms though which have the potential to cause some issues on Earth. For example, in Quebec, Canada in 1989, a rather large solar flare interrupted the power grid, exploding transformers and causing major black outs. There is also the fact that these solar flares can cause damage to satellites in orbit around Earth: they can be hit by high energy particles or damaged by a high currents caused by geomagnetic storms.

    Even so, from Earth these solar flares actual look pretty cool.



    So now the question is, did Doctor Who get it right? The answer is unfortunately not. What is a magical forest of trees going to do against electro-magnetic energy? This is what the show did:



    By the time a solar flare reaches Earth, it just isn't a fire ball anymore and so this not what would actually happen.



    Ok so that's all! I've actual learned quite a bit about solar flares in order to write so that's really cool! Thanks for reading!
  5. Rshadler
    So this is about 24 days too late but...



    So, I have question for you.



    I really hope not. I thought I could use the Christmas Special to talk about the physics of Santa's sleigh, since he was a main focus of the episode and my research yielded so interesting results. (If you still believe in Santa, skip to the very end or you will never be the same again)



    Santa has over 300 million Children to deliver presents to and approximately 31 hours- with different time zones taken in to account- to so. IF we use the census and assume an average number of kids per household, the number reduces to approximately 91 million households to stop at. If we did the math and divided the over the 90 million households by 111,600 seconds in 31 hours (31 hours times 3600 seconds in an hour), we would see that Santa needs to make over 820 stops per second. Santa would need to travel over 70 million of miles and at speeds in excess of 600 miles per second in order to make all the stops in one night. That works out to be around 3000 times the speed of light and impossible to achieve with an man made machine thus far.

    Moving on, could a person survived travelling at those speeds in an open topped sleigh? Could reindeer move that fast? Would the sleigh survive as well?



    Unfortunately, I have some bad news, the answers to all three questions is a resounding NO. Because it is not just Santa travelling at 650 miles per second, its his sleigh, his reindeer, and at least 300,000 tons of toys. That amount of mass travelling at 650 miles per second would create massive air resistance, which would create friction with and heat up the reindeer very quickly and in a similar fashion to a spacecraft re-entering the atmosphere. The reindeer would absorb a massive amount of heat energy- over 14 QUINTILLION (which is 1x1018 and I just learned of this number) joules to more precise. In effect, the reindeer would catch fire instantaneously and vaporize. Santa would subject to an extreme amount of force, effectively pinning to his sleigh with enough force to squash him. I would imagine his sleigh meets a similar fate as his reindeer. In short, if Santa's sleigh could move that fast and he did try deliver presents to all the good boys and girls, than he only tried once.

    Have I ruined your childhood yet?



    Anyway, I thought it was pretty cool, if you avoid the mental image of Santa's sleigh burning up in the atmosphere.



    I'm over doing it with the gifs again, sorry. Anyway, if you want to learn more check out this website, I learned a lot from it and there is some rebuttals to this theory on there as well. Its up to you to make in opinion the theory, so I thought you might like to check out both sides. Thanks for reading!

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