Sound
I used to be able to hear stuff, but I can't any more. What's up with that?
The most likely explanation is that you ran out of air space.
Let me explain. Sound works on the principle of air molecules vibrating at different frequencies. Vibrating molecules have more energy, they are therefore hotter, and as we all know, hot air rises. After a while, the energy of the vibrating particles is depleted, they become 'tired air', and they fall to the ground. Over a period of time (dependent on the volume of the room and the Hubble constant, 5 x 10^4), the amount of air with enough energy to vibrate gradually gets less and less, and eventually, there is no air left in the room able to vibrate.
In order to recharge the tired air, you must super-heat it. The best source of super-heating is our sun; the sun produces 3.8 x 10^26 J every second; this is, obviously, an extremely large amount of power. The equivalent would be 95 thousand million million million 40W light bulbs. If we were to use 40W light bulbs to recharge the tired air rather than the sun, we'd need about 2.7 x 10^14 times more bulbs than are in all the homes in the world. So, the simplest way for us to recharge air is to let it into sunlight. If indoors, open a window. If weather conditions are in a certain configuration, you may notice a layer of tired air left on the ground, and find it necessary to mix it with a layer closer to the window; either shaking a mat or pointing a fan at the floor should do the trick. Quod Erat Demonstrandum.
As a point of interest, because radio stations pump out of a lot of sound (since it has to go a long distance), the government has taken the responsibility of ensuring that the volume of vibrating air used does not exceed the volume of tired air recharged every day; this is why radio stations have to rent air space - can you imagine the chaos which would ensue if they did not?
Helicopters: Round the World The Sensible Way
Helicopters?
Yes, helicopters. Get a helicopter that hovers above the earth for twenty four hours and let the rotation of the world do all the work.
- Up you go...
- The world rotates...
- Land
See? Problem solved!
My crazy friend says the helicopter would move round at the same rate and stay in the same place above the earth
He's crazy. Let's look at the facts.
Find a small object, like a pen, and throw it up in the air and catch it again. Your crazy friend would probably say something like 'now it didn't appear to shoot off to the side as the earth rotates around it, did it?' However, what your crazy friend failed to take into account was the fact that the Earth is round. Since it is round, we're at a slight angle, so throwing it straight up is difficult - we're simply not throwing it up right. See, now throw your pen up again, and take care to throw it straight up. See, it moved a bit!
Another example. If I put selotape on the end of it and throw it up harder, it is true that it stays up in the same spot. But it's attached to the house which is attached to the ground. So it will go round the earth if we could throw the pen hard enough so it sticks to something higher up that isn't attached to anything... like a helicopter!
Your crazy friend should facts - the earth rotates. And if he tries to tell you that the helicopter rotates with it, point out that if it's hovering, it's not attached to anything any more. Why would it rotate if it's not attached?!
See, i've got a pen here, if I tie some string to one end of it, and tie something else to the other end of the string and spin it round, then the pen rotates and the something else goes with it. But if I take the string away with a knife, the other thing falls to the ground! Now, if the other thing was a helicopter, it would be able to stay up in the air. And if the pen was the earth, then the earth would keep moving while the helicopter hovered. Q.E.D.
My crazy friend says that the helicopter would have to be going too fast!
I have often heard arguments about the circumference of the earth at the equator being 24,901.55 miles, and that that means that in order for the helicopter to let the earth rotate beneath it and do a full circle in one day, it would have to travel at 1038 mph.
However, what they fail to comprehend is that it is not the helicopter moving, and that makes their mathematics irrelevant. Take the sun, for example. That's not moving around the earth, it's stationary. Don't make the same mistake as the ancient civilisations did. It looks like it's moving round the Earth, so for our example it is perfect. So the Sun takes 24 hours to 'go' round the earth. Does it look like it's travelling at 1038 mph? No. Q.E.D.
My crazy friend asked me how comms satellites can stay in the same place above the earth?
That's simple. Out in space there is no friction.
We have already established that the earth is spinning at 1038 mph. The massive rockets that blast the communication satellites into space are travelling at 1038mph, and then, when they get into space where there isn't any friction, they stop and let the satellite keep on going. The satellite travels at 1038mph, because theres like nothing to slow it down. They then get their power for maneouvering thrusters through solar power, and microwaves beamed from the ground.
Some people may now start banging on about centrepetal acceleration; well, let me tell you, that is a myth. It started from the conspiracy between the US government and gas companies - it's a way to say 'oh, it costs x billion to fire a rocket into space because you use up all this petrol', and then they buy cheap-ass gas from the gas companies at rediculously over-rated prices, with money from the tax payer. Then they split the profits, and spend it on cool stuff like segways. I'm sure you all saw that photo of George Bush on a segway... just where did you think he got the money to pay for that, eh?
My crazy friend keeps whining about geosynchronous positioning!
If people like these are our "scientists", no wonder we're not making any exciting leaps in technology.
Just say to them 'That's a couple of long words for someone so stupid!'. However, if they are still not persuaded, talk it through with them, they'll soon understand.
These conversations will usually start with your crazy friend saying something like 'Suppose someone threw a rock horizontally. Then we know that it will follow a parabolic path to the earth because of the attraction of gravity. If we threw it harder and from a bigger height it would travel much further before hitting the earth.' You can smile and nod at this.
They will then continue; 'If we threw it harder and from a bigger height it would travel much further before hitting the earth. Now, the earth is roughly spherical, which means that if the rock is thrown hard enough horizontally from some height, then it a point would be reached where it dropped down at the same rate that the Earth curved away, so that it would keep going around the Earth!' You can smile and nod at this too.
However, they may now say 'Gravity pulling the rock towards the center of the Earth actually makes it go round the Earth if the rock has sufficient speed. The rock MUST be travelling for it to achieve a geosynchronous position.' This is where they make their mistake.
There is no relevance between their previous points and geosynchronocity. If you throw a rock horizontally, does it stay in the same place above the earth? NO! The two things are completely unrelated.
Slap your crazy friend and call in the men in white coats.
So just how do helicopters work then?
The blades on the top of them only let them go up and down. Time dictates where you land; the further away you go, the longer it takes.
'But what if you want to go in the opposite direction' I hear you ask? Well, that's why they put little jet engines on military helicopters.
So how come it took Phileas Fogg 80 Days?
He didn't have a helicopter, duhh.