Just off my head

:Lasers

I think laser pointers/pens, whatever you would like to call them, are great.
Yeah, they can blind you but that's why you don't look into the laser bit.

Now, as far as I know with my scientific knowledge, the red dot doesn't fade, it just keeps going, right?
Now is anyone else amazed by this? Three little watch batteries in a shiny little pen create a straight red line of light that goes on forever. Obviously there is the speed of light to consider, but does that mean you could shine it on the moon? I am guessing you would have to work out where the moon is going to be in the future (about 8 minutes I think, or is that the light from the sun reaching us? I can't remember. Anyway...) and shine the pointer to that spot. Then look through with a really powerful telescope for a red dot the size of a pea to appear on the surface (or does the laser dot increase in size as it travels, like a torch beam only with a narrower cone of increas-ion/tion/ingness?).

My point is along the line of "from tiny acorns grow mighty oaks" only less leafy and woody. This little thing is capable of such greatness a (possible) red dot on the side of the moon, and who knows how much further, the end of the universe maybe, round the universe and back into my eye maybe. All from a thing the size of my finger powered by less than it takes to power an electric toothbrush.
You could light up a dark corner of the universe with it but it isn't powerful enough to make your car go from A to A and a half. And its invisible until it touches something.
 I am guessing dust and debris will disrupt the beam, but until it hits a solid stationary object it will just keep going.... forever. !_!

Now, I can comprehend that little dot travelling through space until it hits something but I still can't work out how Vinyl works.
There is a tiny little microphone, I know that. There are grooves and bumps on the vinyl itself, I know that. The microphone goes in the grooves and over the bumps, I know that.
Sound comes out that is not the sound of a microphone being dragged over a plasticy surface, I don't understand that. How can the bumps on the record create the sound of a full band performing to a live audience with the boom of the drums, the yell of the crowd and the rasp of the singer all come through as if it were there. I understand the way CD works, laser (laaaaser) picks up digital data and plays it digitally, but its a microphone bumping away and it sounds like some one singing, or anything at all!
What really boggles my mind is when I try to picture how it was recorded.... boggles.
And Cassettes, bloody hell.
I have to go and lie down.

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