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Non Life Sciences
Physics, Astronomy & Cosmology
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06/02/2005 17:04:57 »
I`m in a U3A group called Science and Technology. I`m the only one with a physics degree. It`s fifty years old and I have scarcely used it. A mathematician asked me how a solid lump of matter hangs together. I`d never tbought about it. I said " electromagnetic forces". He said " But atoms are electrically neutral". I had no answer. I fancy there are two answers at least - one for a crystal, one for a glass-type solid. If it is electromagnetic, what attracts what ?
By the way, I`m an infant with computers. Is it really necessary to have all this Gatesian password-login-logoff-logout business? If I write you a letter or phone you I don`t need a password, so why now ? Won`t a simple email do ?
Reply #1 on:
06/02/2005 17:35:43 »
That can be a long answer. Short answer: Atoms, protons and electrons, hang together with EM forces. The nucleus, protons and neutrons, hangs together with the nuclear strong force, which is the leftovers of the color force that makes the quarks hang together.
The atoms hang together with various kinds of EM forces that are leftovers from the EM forces that bind the electrons to the protons. Chemically, we call them ionic forces, covalent forces, Van-der-Wals forces. These forces are produced by assymmetries in the EM forces holding atoms together. When the EM forces are symmetric, as in the noble gasses, then they don't hang together.
"F = ma, E = mc^2, and you can't push a string."
Reply #2 on:
06/02/2005 21:27:03 »
Password wise, it stops random people and programs wandering on and spamming(flooding posts) everything without the moderators knowing where they camne from [
] Plus we don't want any old riff raff on here [
wOw the world spins?
wOw the world spins?
Neilep Level Member
The Naked Scientist
Reply #3 on:
08/02/2005 08:17:39 »
Mike - great to see you finally made it onto the forum !
"I never forget a face, but in your case I'll make an exception"
- Groucho Marx
I never forget a face, but in your case I'll make an exception - Groucho Marx
Reply #4 on:
16/02/2005 20:57:34 »
Thanks a lot to all of you: Mollin, Ultima and Chris.Most interesting, and astonishing that some materials are so strong by virtue of those leftovers. I`m a Fawlty fan myself and I do agree about riff-raff. It`s entirely due to Chris that I got on at all. He revealed the secret rule about spaces in passwords and constructed a valid one for me,possibly circumventing several other Gatesian obstacles, and told me to do some logonning, which I had overlooked. I see also by experiment that to access your kind replies I have to click on the word(s) in the left-hand column.
All set up now.
Naked Science Forum GOD!
Reply #5 on:
16/02/2005 21:17:11 »
Welcome Mike....don't be stranger now.
'Men are the same as women...just inside out !'
Men are the same as women, just inside out !