Fun with Physics

Fun with Physics


    I hated physics class in high school.  I still have nightmares about force problems; all that complex math.  Only later in life did I learn to appreciate it, because I see it in every aspect of our lives.  There’s a reason we don’t all fly out into space as Earth careens through space at over 18,000 mph — its gravitational effect keeps us grounded, you might say.  If you think physics is boring, consider this:  what’s the temperature at which water freezes — 32 degrees Fahrenheit.  But what’s the melting point of ice — frozen water?  It’s also 32.  How can this be?  The difference is one single calorie of heat, one way or the other.  Don’t you think that’s fascinating?
    I’ll bet you’ve had fun with physics, too, if you’ve been to the fair.  There’s a ride, a huge cylinder section people stand inside, backs to the wall.  It starts spinning, and when it attains a certain rotational velocity, the floor drops out, but centrifugal force keeps you pinned to the wall.  That’s fun, right?  Hang around, because I’m about to give you some health and beauty tips, taking advantage of basic physics.
    First, though, we have to dispel a common misconception about time travel repeated in books and films.  Let’s get serious.  You can’t just set coordinates for a given time and — zap — you’re there.  There’s never anything about space or location, and that’s very dangerous.  Say you decide to go six months into the future, or the past.  Either way, you’re going to end up on the opposite side of the Earth’s orbit, in deep space, aren’t you?  You had better be wearing a pressurized suit.  Look at it this way; nothing can be thought of as existing at any particular time, without reference to its location.  Similarly, you can’t be at any location without a time attached to it.  From what we know, or think we know, they are part of the same coordinate system.  And not only does the Earth orbit the sun, but the solar system is also orbiting the center of the galaxy every 200 million years or so.  AND we bob up and down on the ocean of space.  Therefore, you had better get your math exactly right.  Miss a decimal place and you could be, well, history.
    There are lots of silly ideas about time travel.  Some people say the absence of time travelers proves a time machine will never be invented in the future.  What, they’re going to go around advertising it?  Then there are the paradoxes, like when you go back and kill your grandparents.  How can you exist in the future to time travel then?  All this stuff is fun to play with, but we have other amusements.
    Would you like to look younger?  We all would, I suppose.  Well, it happens every time you look in the mirror.  Say you stand a foot away.  At the speed of light, it takes about a nanosecond — that’s a billionth — for your reflection to bounce back to your eyes, so you’re really seeing a younger version of yourself.  The further you stand from that mirror, the younger you’ll look.  Isn’t that amazing?  Of course, those of us wanting the most to look younger, are older, and our vision is deteriorating.  At some point these disparate elements will cancel each other out.
    How would you like to lose weight?  It’s very easy.  Our weight is a function of the relationship between our mass and that of the Earth, or more properly, the center of gravity of Earth’s mass.  If you’re on the twentieth story of a building, you will weigh a small fraction less, because you’re further from the center of the Earth.  The moon has only 1/81st the mass of Earth, so it would seem that someone standing on its surface would weigh 1/81st as much as they do on Earth.  But we weigh 1/6th of our Earth weight.  That’s because on the moon, we’re only 1000 miles from its center of gravity, and on Earth we’re about 4000 miles from its center.  So if you want to lose a lot of weight, climb a mountain.  Of course, you’ll lose a lot more just in the effort to reach the summit, but it all counts, doesn’t it?  I should add that rather than compliment someone by asking if they’ve lost weight, it’s really more proper to ask them if they’ve decreased in mass.
    Here’s some physics that isn’t so fun, at least for me.  It involves the principle of interference, particularly radio waves.  My radio is about four feet away, and I’ll put it on a station where I can hear it clearly, but when I stand up or sit back down, it’s static.  This is because our bodies have a very small magnetic field, but it’s apparently enough to disrupt the radio signal.  It’s very frustrating.
    Well, how could we have fun with physics without mentioning Schrodinger’s cat?  Are you securely buckled in?  Okay, this is tough for me, too.  At the quantum level, our normal laws of physics sort of break down.   Particles have demonstrated the ability to be in two places simultaneously (this state is known as superposition, in case you’re still awake).  Or light can be shown to be either a wave or particle, depending on what you’re looking for.  In 1935 the Austrian physicist Erwin Schrodinger proposed a theoretical experiment.  You’d put a cat into a steel box, so you couldn’t see it.  Also in the box is a vial of hydrocyanic acid, a radioactive substance.  If a certain amount of atoms decay, a sensor will trip a hammer which will break the vial, killing the cat.  From the point of view of the observer, the cat could be either dead or alive at any given time.  From the quantum point of view, the cat is both dead and alive, until the observer opens the steel cage to see.  In essence, the observer is affecting the outcome, or there can be no outcome until the observer makes the measurement.  Frankly, all of this sounds to me like a lot of mental masturbation, even if it’s fun to think about.  Even Schrodinger himself admitted later in life, that he wished he’d never met that cat.
    Still, these are intriguing ideas, because of the implication that reality is elastic, and that we interact on a fundamental level with everything around us.  If you’re religious, or non-religious but consider yourself spiritual, I would think you would find this a reassuring thought.  I can tell you, it works for me.  Just as intriguing is the idea that Western science is moving ever closer to Eastern mysticism, and I find that a very hopeful sign in our continuing search for the nature of reality.  I’ll leave you to think about this:  Einstein showed that space has curvature, so if I had a powerful enough telescope, would I see the back of my own head?

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