And what country can preserve its liberties if their rulers are not warned from time to time that their people preserve the spirit of resistance? Let them take arms. The remedy is to set them right as to facts, pardon and pacify them. What signify a few lives lost in a century or two? The tree of liberty must be refreshed from time to time with the blood of patriots and tyrants.
Ah, the ellipse, neat stuff huh? Great animation, thanks, wish we had had this back in the long ago past when I studied math. It certainly illustrates what could only be described with lines on a blackboard.
This is the principle behind the whispering gallery. There is supposedly a church somewhere in Europe, IIRC where the confessional is at one focal point and the other is out in the pews, or some such.
When I was a kid, I school-visited a big-city science museum, that had, amongst other things, a pair of 10 foot or so, parabolic dishes at opposite ends of the room, easily a 100 feet or so apart, with noisy exhibits in between.
They were aimed at each other across the room, and raised up a bit for a clear "view". 2 people could converse in normal voices, as though face to face, but the person less than a foot away (out of the focal point) could not hear the person at the other end of the room.
Not dissimilar to how gamma rays from the fissile Plutonium get focused on the Deuterium-Tritium fuel in an H-bomb...so they say.
ReplyDeleteAh, the ellipse, neat stuff huh? Great animation, thanks, wish we had had this back in the long ago past when I studied math. It certainly illustrates what could only be described with lines on a blackboard.
ReplyDeleteWOW!
ReplyDeletePerhaps it is more accurate to say that Angle of Incidence Determines the Angle of Reflection - not equals.
ReplyDeleteMake a pool table like that, and demonstrate it IRL, rather than animation.
ReplyDeleteThis is the principle behind the whispering gallery. There is supposedly a church somewhere in Europe, IIRC where the confessional is at one focal point and the other is out in the pews, or some such.
ReplyDeleteHilarity ensues....
When I was a kid, I school-visited a big-city science museum, that had, amongst other things, a pair of 10 foot or so, parabolic dishes at opposite ends of the room, easily a 100 feet or so apart, with noisy exhibits in between.
ReplyDeleteThey were aimed at each other across the room, and raised up a bit for a clear "view". 2 people could converse in normal voices, as though face to face, but the person less than a foot away (out of the focal point) could not hear the person at the other end of the room.
Neat stuff, when you're 10 years old.