Recent content by antistrophy

I think it would be interesting to calculate how much water is needed to raise the sea level one foot (for instance). First, since it is a globe, one foot change in radius will increase the surface area by the square of the radius excluding where land mass is, except that by raising the height...

...and curiously the gun will still kick the same due to the force needed to "stop" bullet from going the speed of the train. :smile:

What model would you suggest for relating voltage and current to things already familiar to a high school student?

Okay let's start here. Why not? The nuclear binding energy can be, and the electron binding energy can be, so why not gravitational energy? Does a satellite have more mass orbiting the Earth than it does on Earth?

This may have been answered elsewhere but I couldn’t find it. Is it the case that gravitational potential energy will add mass to an object the same way nuclear binding energy will? In other words, as I move an object away from Earth is it gaining mass in the form of the stored energy I put...

Okay, I get it now. The initial movment of the electrons near the battery before the EM wave has gone around is very small and stops immediately. Something like "compressing" rather than moving. And as rcgldr says I suppose when the waves cross at the back side the full current travels back...

I hate to say this, but I don't think the electrons next the battery move first, I think they have to move all at once because of this: If instead of wires, I touch a capacitor to the positive side and a capacitor to the negative side but do not touch them together, do either of them get the...

Drat. For a second there I thought I understood. Can I ask simpler questions? 1 Is the voltage difference moving the electrons? 2 Does the voltage difference move around the circuit (i.e. if I connect the wires to the battery the voltage difference (in the battery) has moved to the end of...

Here is a good explanation of light being made from all sorts of things http://www.webexhibits.org/causesofcolor/made.html the rest of the site is good as well

It sounds like (in simpler language) we can think of the EM wave as a longitudinal pulse traveling down both sides of the wire (somewhere around c) away from the battery. This initially moves electrons but as the pulse reaches the far side if it can’t continue around the circuit the electrons...

I was afraid this might be the case but I still have the problem of the lights lighting before the voltage has gone around the circuit. (and determined that it is closed)

okay so this voltage wave will travel down the wire (from both +ve and -ve ends of the battery?) and if they meet (closed circuit) then electrons move all at once? In other words at the far side of the circuit put a switch. How long before we see a voltage difference and did any electrons...

So basically what we are saying here is that the electrons closest to the battery are affected first? Forget the problem about the resistance; just think of it as an extremely short time period on a normal circuit.

In trying to understand electricity I thought of the following: If I set up a wire one light year long, stretching out into space ½ a light year out and ½ a light year back, and connected a series of light bulbs all the way around the wire, and then connected a battery (large enough to handle...

AH HA! 100% clear as day, thank you very much, well done. I suspect the law for the lenses has something to do with the magnification being equal to the image distance over the object distance. Thanks again tiny tim. And thanks Syhprum for your reply as well.