HOw to Explain Gravity

dannat (Daniel) · #1 13-07-2008, 04:34 PM

I am wondering how could I succintently explain what we know / don't know about gravity to a 15yr old intelligent girl thinking of a science career.

I have told her I don't really believe it is a straightforward force, more of a natural phenomenon. Also probably does not quite fit into the fundamnetal forces of physics (like electro-mag etc)

Any ideas are welcome - so for xelasnave & others GO WILD, with your responses and wild theories -

NB Please keep them to 6 LINES!

thanks daniel

renormalised (Carl) · #2 14-07-2008, 12:03 AM

Gravity is the change in the geometry of spacetime generated by a massive object sitting in spacetime. However, in terms of everyday experience, gravity is the force which a massive object generates that attracts other objects to it...e.g. the gravity of the Sun helps keep the Earth in orbit about itself. Or, makes an apple fall to the ground when an apple breaks off an apple tree.

Daniel....gravity is a natural phenomenon as well as a "force" and is one of the fundamental "forces" of nature (like EM, WN and SN). It's the weakest of all the "forces"...some 10^39 times weaker than EM. Yet its influence is universal and overwhelming. What we don't know about gravity is what it actually is... we call the particle that supposedly carries the gravitational "force" a graviton. However we have never detected gravitons....they're hypothetical. We also don't know why it's so weak. We have ideas as to why it is, but they remain speculation. In actual fact, we know very little about gravity and what it is, other than what we can observe.

bojan · #3 14-07-2008, 08:08 AM

Gravity manifests itself as attraction force, proportional to attracting masses and inverse proportional to square root of distance between them.
As for "what it really is"... we do not know at the moment, and the future theories will tell us more.
This is as wild as you should go with thing like that... not to confuse people (too much) :-)

dannat (Daniel) · #4 14-07-2008, 08:17 AM

thanks guys this is good!

erick (Eric) · #5 14-07-2008, 12:21 PM

If she is very bright and interested, she might cope with Richard Pogge's lectures:-

http://www.iceinspace.com.au/forum/s...ad.php?t=24169

He deals with gravity in a lecture in Astronomy 161 (Newtonian) and then from a Relativity perspective in Astronomy 162.

There are lecture notes and podcasts.

renormalised (Carl) · #6 14-07-2008, 01:26 PM

Most 15 year olds would be lost trying to comprehend what are essentially university level subjects, Eric. Unless, of course, she is gifted. In which case, it would be prudent to introduce her to these subjects as trying to "reduce" them to "more manageable" levels will only bore her to pieces and make her lose interest.

renormalised (Carl) · #7 14-07-2008, 01:27 PM

Daniel, if she has any problems with anything you introduce her to, feel free to contact me here and I'll help in any way I can.

TrevorW · #8 14-07-2008, 02:42 PM

1. All objects are affected by gravity the more massive it is the more gravity it has
2. The effect of gravity diminishes with distance
3. If an objects falls then there is gravity
4. If an object floats without other forces applied to it then there is no gravity
5. Gravity can affect other forces.
6. Gravity exists in normal space time

sjastro · #9 14-07-2008, 02:54 PM

Quote:

Originally Posted by renormalised

Most 15 year olds would be lost trying to comprehend what are essentially university level subjects, Eric. Unless, of course, she is gifted. In which case, it would be prudent to introduce her to these subjects as trying to "reduce" them to "more manageable" levels will only bore her to pieces and make her lose interest.

Reminds me of a 16 yr old girl who won a bronze medal at the Australian Physics Olympiad and went on to represent Australia.

I gave her my Uni books on GR and Particle Physics. These books required a fairly sophisticated knowledge of mathematics but it proved no obstacle for her. An amazing intellect but I wonder how she relates to her peers.

Regards

Steven

renormalised (Carl) · #10 14-07-2008, 04:14 PM

She probably can't because she's so far ahead of them that they just can't understand her. She's more than likely far more mature than they are. Not that she may look down upon them, she may even want to try and make friends, but her peers probably think that she's weird. More than likely, she's been picked on since she was a small child, by the other children. Probably had/has nicknames like mad scientist, Prof. Einstein etc. Luckily for her, these days they have organisations in some states which encourage students like her and work to their skills and talents.

I'll bet she could probably read at a very early age. Always been interested in Science.... I wonder if that all fairly describes her, Steve?

erick (Eric) · #11 14-07-2008, 04:16 PM

Yes, and it's sad how gifted children often have to "dumb down" to keep friends. I've seen it happen - they know they have to keep quiet and not answer every question else they get into trouble with peers - it's a pity.

renormalised (Carl) · #12 14-07-2008, 04:28 PM

Exactly, and what's worse is as they get older, having not being able to fully express themselves and work to their fullest capacities....given challenges to stretch them and further their development.... they end up just like the rest of their peers. They either lose interest in learning entirely or end up developing bad habits that stifle them. Then, if and when they go further with their education, they're just average students and not the exceptional students that they could've been.

sjastro · #13 14-07-2008, 06:03 PM

Quote:

Originally Posted by renormalised

She probably can't because she's so far ahead of them that they just can't understand her. She's more than likely far more mature than they are. Not that she may look down upon them, she may even want to try and make friends, but her peers probably think that she's weird. More than likely, she's been picked on since she was a small child, by the other children. Probably had/has nicknames like mad scientist, Prof. Einstein etc. Luckily for her, these days they have organisations in some states which encourage students like her and work to their skills and talents.

I'll bet she could probably read at a very early age. Always been interested in Science.... I wonder if that all fairly describes her, Steve?

I don't know her very well. According to her mother she's had trouble making friends her own age which is obviously not a surprise.

She went to Melbourne Uni with the intention of gaining a career in Particle Physics. She was able to go straight into the second year maths units, as her mathematical abilities (and knowledge) demonstrated in the Physics Olympiad were way above the requirements of the course.

The last I heard of her she dropped out of Uni and is in a classical choir where she is making friends. Maybe she found Uni boring, hopefully she will go back as Science needs people of her talent.

At least she is making friends which ultimately is more important than an education.

Regards

Steven

Suzy_A · #14 14-07-2008, 06:39 PM

No such thing as gravity: the Earth just sucks.

AlexN · #15 14-07-2008, 06:54 PM

Gravity does not suck.

renormalised (Carl) · #16 14-07-2008, 07:22 PM

Quote:

Originally Posted by sjastro

I don't know her very well. According to her mother she's had trouble making friends her own age which is obviously not a surprise.

She went to Melbourne Uni with the intention of gaining a career in Particle Physics. She was able to go straight into the second year maths units, as her mathematical abilities (and knowledge) demonstrated in the Physics Olympiad were way above the requirements of the course.

The last I heard of her she dropped out of Uni and is in a classical choir where she is making friends. Maybe she found Uni boring, hopefully she will go back as Science needs people of her talent.

At least she is making friends which ultimately is more important than an education.

Regards

Steven

True, having friends and becoming socially competent is very important, but so is an education. However, the most important thing is that she is enjoying herself, having fun and doing what she wants to do. I know of many people with excellent school results that did no good at uni. Simply because they couldn't handle the pressure, or the responsibility of having to be independent in their studies.

AlexN · #17 14-07-2008, 07:33 PM

Quote:

Originally Posted by renormalised

I know of many people with excellent school results that did no good at uni. Simply because they couldn't handle the pressure, or the responsibility of having to be independent in their studies.

mmm, As do I, It seems that without constant direction from teachers a lot of people just cant get their butts into gear. I was one of them... I'll be going back and finishing my course in the next year or so... Bit older and a bit wiser hopefully...

renormalised (Carl) · #18 14-07-2008, 07:50 PM

Quote:

Originally Posted by AlexN

mmm, As do I, It seems that without constant direction from teachers a lot of people just cant get their butts into gear. I was one of them... I'll be going back and finishing my course in the next year or so... Bit older and a bit wiser hopefully...

That's good to hear

Being highly intelligent and good at school (or even being gifted) is no guarantee that you'll do well at uni...or anything else for that matter.

sjastro · #19 14-07-2008, 08:24 PM

Quote:

Originally Posted by renormalised

True, having friends and becoming socially competent is very important, but so is an education. However, the most important thing is that she is enjoying herself, having fun and doing what she wants to do. I know of many people with excellent school results that did no good at uni. Simply because they couldn't handle the pressure, or the responsibility of having to be independent in their studies.

I think anyone who represents their country in a Physics Olympiad is probably well equipped to handle the pressures of a University environment, and be ultra competitive to be at the top of the class.

University life however can be a very lonely experience without friends.

Steven

renormalised (Carl) · #20 14-07-2008, 08:53 PM

Quote:

Originally Posted by sjastro

I think anyone who represents their country in a Physics Olympiad is probably well equipped to handle the pressures of a University environment, and be ultra competitive to be at the top of the class.

University life however can be a very lonely experience without friends.

Steven

You would think so, but I know people who couldn't handle it anyway. They needed a structured env' with a pushing influence (a teacher) to keep them motivated.

Yes it can be, but if you get along with your fellow students it's not all that lonely if you don't socialise with them on a "friends" basis. I suppose, though, it depends on your personality and how well adjusted you are.