Physics In the Playground

[Rawhide]

Physics in the Playground!

[noparlpf]

Physics in the Playground!

My favorite Physics presentation EVER.

[RebelRogue]

It's about 550 nano-meters.

I half expected a response like this, but I ran with it anyway

[grimbold]

Physics in the Playground!

made of win!

[JCarter426]

I have to say that just the concept of a wave surpasses my comprehension. I understand a wave of liquid or a wave of pressure, or even a sine wave as a mathmatical function.

But a wave of electromagnetism? The wind tastes awfully blue today.

Then prepare to have your mind blown...

GRAVITATIONAL WAVES.

[Pie Guy]

Then prepare to have your mind blown...

GRAVITATIONAL WAVES.

There are no words.

[Battleship789]

I have to say that just the concept of a wave surpasses my comprehension. I understand a wave of liquid or a wave of pressure, or even a sine wave as a mathmatical function.

But a wave of electromagnetism? The wind tastes awfully blue today.

As others have mentioned, wave-particle duality (and waviness in general, especially with regards to forces [EM, gravity, etc.]) is a fundamental part of modern science. Everything has WPD, even macroscopic objects, however, the wavelengths of macroscopic objects are much to small in comparison to their physical size for this to be observed/meaningful.

Example: The wavelength of an object that masses 100 kg (say, an adult human) and is moving at 5 m/s (a meh running speed), has a wavelength of 1.32*10^-36 m, or ~10^36 times smaller than said human. Contrast this to an electron moving at 5 m/s (not going to happen, but it is useful for comparison), the wavelength is 1.45*10^-4 m, which is ~10^11 times larger than the classical radius of an electron. So we can observe wave properties for an electron, but not a human.

More fun with the dual slit experiment: if you dim the light down a lot, so that you know that only one photon is going through the experiment apparatus over some time, you still get a wave pattern if one collects data for a long period of time. However, each individual photon hits a single spot on the collection screen as if it were a particle (like a BB hitting a wall) but the locations where it can hit are determined by the probabilities due to the wave (due to the photon interfering with itself)! So a location where wave interferrence would cancel out (leaving a dark spot in a bright light experiment) will never have a "hit," and it is more likely for the hit to occur in a area where the wave interference adds up. You can never be sure where the photon will hit, only where it won't hit.

And the dual slit experiment has been done with stuff much larger than electrons: 60 Carbon buckyballs have been used in a dual slit experiment, and they did indeed show wave properties, despite their size.

You mean it's a series of alternating layers of magnetic and electronic fields?

Not really. To reiterate: A moving magnetic field induces (creates) an electric field that is perpendicular in direction to both the magnetic field and the direction in which the magnetic field is moving. (This is also true for the reverse, a moving electric field induces a magnetic field...) So the magnetic field and the electric field oscillate around a line (that points in the direction of movement) and are perpendicular to each other.

Here is a .gif that shows what is happening: gif.

[Drolyt]

Okay, so I have a sort of odd question. In some works of fiction magic interferes with "technology". I put technology in quotes because it seems a bit random what counts as "technology". Anyways, a thought occurred to me, but I don't know enough physics to know if it would work. A magnetic field interferes with electronics, correct? So could we say that that magic produces an electromagnetic field, or even works on electromagnetic principles? If so, what effects would a field capable of interfering with electronics have in general? For example, would it have other effects besides interfering with electronics?

[JCarter426]

I dare say it should interfere with compasses. But if you're looking for a scientific explanation for it, I'd say magnetism isn't the best one. Magnetic fields don't mess with technology in the way that magic does in certain fictional works - or at least, the strength of a magnetic field required for one to do such would be so enormous that a wizard would have other problems beside messing up someone's computer. Static electricity is less problematic; for one thing, it's directly harmful to a variety of technical components (magnets aren't, it's just that hard drives use magnets to store data, so other magnets would interfere, of course), but more importantly, you don't need a bolt of lightning to do it.

I prefer any explanation that involves quantum mechanics though, though. In any universe with science as we know it, magic must involve laws physics that are fundamentally different from that we understand. Assuming we haven't gotten everything in physics wrong, there must be entirely separate forces that we haven't discovered, and these forces must involve likewise undiscovered subatomic particles. And how they would react with any other system that involves the delicate manipulation of subatomic particles - e.g. all electronics - I can't say, since we haven't discovered these particles. But it's probably not something good.

[Grinner]

On the other hand, if you're looking for a semi-scientific to pseudo-scientific explanation, much fringe science associates forms of magnetism with the supernatural. Take for instance E.V.P., certain interpretations of ghosts, a couple of takes on psychics, religious experiences, and life itself.

[Knaight]

Okay, so I have a sort of odd question. In some works of fiction magic interferes with "technology". I put technology in quotes because it seems a bit random what counts as "technology". Anyways, a thought occurred to me, but I don't know enough physics to know if it would work. A magnetic field interferes with electronics, correct? So could we say that that magic produces an electromagnetic field, or even works on electromagnetic principles?

Given that "technology" seems to almost always include guns, and the magnet needed to screw up gunpowder ignition is going to cause much bigger problems than messing with "technology" (we're talking about something that is pressing the electrons of every atom towards the nucleus, or stripping them away) it doesn't seem to work.

[factotum]

It would probably be easier to assume that an intense magical field warps the values of some physical constants in such a way that things stop working...of course, you then have to figure out how a living being remains that way inside such a field! In short, let's just say a wizard did it.

[Drolyt]

Given that "technology" seems to almost always include guns, and the magnet needed to screw up gunpowder ignition is going to cause much bigger problems than messing with "technology" (we're talking about something that is pressing the electrons of every atom towards the nucleus, or stripping them away) it doesn't seem to work.

Well, I was thinking it wouldn't include guns. At least, I can't imagine how it could. Guns, or at least some guns, aren't terribly complicated devices (I mean to say that the principle behind them is fairly basic, not that they are easy to engineer). I can't imagine how you would interfere with guns without interfering with almost everything.

In short, let's just say a wizard did it.

That would be easier, yes, but it would also defeat the purpose of me asking.

[noparlpf]

Well, I was thinking it wouldn't include guns. At least, I can't imagine how it could. Guns, or at least some guns, aren't terribly complicated devices (I mean to say that the principle behind them is fairly basic, not that they are easy to engineer). I can't imagine how you would interfere with guns without interfering with almost everything.

I don't know. A basic gun isn't hard to make. Remember that episode of Star Trek TOS? I think it was "The Arena", but I might be mixing up names.

[Yora]

Mythbusters tried to build that thing Kirk had made, and theirs didn't work at all.
Not to say it can't be done, but it's certainly not as easy as Kirk makes it look like.

[shawnhcorey]

Of course not. Kirk missed a step. It involves wine and urine (don't ask).

[Grinner]

Of course not. Kirk missed a step. It involves wine and urine (don't ask).

I'm now asking.

[noparlpf]

Mythbusters tried to build that thing Kirk had made, and theirs didn't work at all.
Not to say it can't be done, but it's certainly not as easy as Kirk makes it look like.

I was joking by making the Star Trek reference. It's not quite that simple. It is still pretty simple to make a basic gunpowder projectile launcher.

[Grinner]

I was joking by making the Star Trek reference. It's not quite that simple. It is still pretty simple to make a basic gunpowder projectile launcher.

The trick is not blowing your hands off while doing it.

[Drolyt]

I'm now asking.

I'm not exactly sure what he is referring to, but I have heard you can make gunpowder out of urine. I'm not clear on the details.

[Grinner]

I'm not exactly sure what he is referring to, but I have heard you can make gunpowder out of urine. I'm not clear on the details.

I've heard something like that in the past.

The idea was that urine supposedly contains a high concentration of oxygen. If you mixed some blackpowder, urinated on it, and formed it into cakes, then the increased oxygen content would cause it to burn faster, thus more intensely.

I've never tried to verify that though.

[shawnhcorey]

I've heard something like that in the past.

The idea was that urine supposedly contains a high concentration of oxygen. If you mixed some blackpowder, urinated on it, and formed it into cakes, then the increased oxygen content would cause it to burn faster, thus more intensely.

I've never tried to verify that though.

Actually, the urine was to make the cakes. Look up gunpowder in Wikipedia and search for "wine-drinking bishops".

[noparlpf]

The trick is not blowing your hands off while doing it.

I've been warned of that before. Still have all ten fingers, and I'm nearly eighteen! This is a good record!

As for the urine--distilled spirits works better. It's the same principle of wet-mixing they use in pharmaceuticals these days.

[Yora]

Looking on information how to make fascinating and realistic fantasy castles, I found this series on engineering on youtube.
It's on a very basic level and rather brief on most topics, but if you don't have any previous knowledge except for what you figured out by playing with wood blocks, sticks, and mud, I find it a very easy introduction. Didn't think it's possible to understand the basic principle of buckling without an advanced degree in physics.
But all those questions like "How do towers topple without being pushed over", "How tall can you stack bricks until the lowest brick at the bottom gets crushed by the weight", or "could you make multi-story buildings with floors made from stone beams without them snapping" (to which the answer is "not in a practical way") are all really not that difficult when someone explains to you the very basics of structural engineering.

[Grinner]

Looking on information how to make fascinating and realistic fantasy castles, I found this series on engineering on youtube.

Thank you for sharing.

[Drolyt]

Looking on information how to make fascinating and realistic fantasy castles, I found this series on engineering on youtube.
It's on a very basic level and rather brief on most topics, but if you don't have any previous knowledge except for what you figured out by playing with wood blocks, sticks, and mud, I find it a very easy introduction. Didn't think it's possible to understand the basic principle of buckling without an advanced degree in physics.
But all those questions like "How do towers topple without being pushed over", "How tall can you stack bricks until the lowest brick at the bottom gets crushed by the weight", or "could you make multi-story buildings with floors made from stone beams without them snapping" (to which the answer is "not in a practical way") are all really not that difficult when someone explains to you the very basics of structural engineering.

Cool, thanks.

[Rockphed]

It's very much decided. They're quantum objects (as is everything), which means that they're neither, but in different contexts they may act similar to particles or waves.

Technically, quantum means it exists only at integer multiples of Planck's constant.

[Jimorian]

I'm not exactly sure what he is referring to, but I have heard you can make gunpowder out of urine. I'm not clear on the details.

It's the nitrates in urine, although human urine is far from the best source. Pig urine is much better, and guano is even better, which is the reason why the bird guano cliffs in Chile were considered one of the most important MILITARY resources in the world during WWI. Being cut off from this source was the single reason Germany developed artificial means of making nitrates in bulk.

[shawnhcorey]

Technically, quantum means it exists only at integer multiples of Planck's constant.

Sorry, no. Quantum means they exists at discrete energy levels, as opposed to continuous ones. They are not integer multiples.

[Asta Kask]

I've discovered that all animals with sensitive electrolocation live in water? Is this because water conducts electricity more efficiently or is there something else going on? Or is it just chance playing me for a fool?