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- Thread starter Fractalm
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Nugatory

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One meter is going to be hard to do, because the effects are so small at that scale (Consider, for example, that the force of gravity at the earth's surface is essentially indistinguishable from the force one meter higher - and that's with the entire mass of the earth contributing to the curvature between those two points).

However, there are three examples that you may find helpful in explaining GR at a high-school level:

- Search this forum for the excellent video put together by our member @A.T. (who will probably point you at it if he's listening).

- Google for "Flamm's paraboloid". Be sure that read and understand the mathematical description of what it is - it's easy t misunderstand it if you just look at the picture.

- Google for what John Wheeler called the "ouch radius", the conditions under which the curvature is great enough that to be felt across the one-meter or two-meter scale of the human body.

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It's just not true that gravity is a stretching of space.

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No, that isn't what general relativity says. (And you're now referring to stretching spacetime, which is different from your original discussion of stretching space.)but general relativity isnt that what it presents? that gravity is a stretching effect of the spacetime?

It's possible to present general relativity without a lot of mathematics, but that's different from getting it wrong.

A better place to start this discussion might be by talking about what your own background is and where you've gotten your previous information about GR. We might then be able to point you to, e.g., a book at the right level for you to read.

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when i refer to space, of course i refer to spacetime....

i wish that someone could be clear of what it is the proper elementary (level of practical mathematics) example for general relativity, and not just to declare what it is not...:)...

If i wanted to search by myself i wouldnt have asked you for a straight answer :)....

thanks anyway for your time!...

- #8

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I don't know what you mean with "stretched"... Anyway, it was rather well explained by Einstein in 1916 when discussing the weak field approximation in his scientific overview of GR, and you can read it for yourself on p.197, 198 of the English translation, here: http://web.archive.org/web/20060829045130/http://www.alberteinstein.info/gallery/gtext3.html

His explanation of rods and clocks (leaving out the derivations) is very suitable for high school students.

- #9

A.T.

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You can look at the articles here, starting from the bottom:

http://www.relativitet.se/articles.html

Try to get this book:

Relativity Visualized by Lewis Carroll Epstein

http://www.physics.ucla.edu/demoweb..._and_general_relativity/curved_spacetime.html

Some videos:

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thanks everyone of you!....

- #11

martinbn

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If you have a PhD in physics, then you should be able to follow a standard text on general relativity. Why do ask for an elementary example?

when i refer to space, of course i refer to spacetime....

i wish that someone could be clear of what it is the proper elementary (level of practical mathematics) example for general relativity, and not just to declare what it is not...:)...

If i wanted to search by myself i wouldnt have asked you for a straight answer :)....

thanks anyway for your time!...

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