Naked Science Forum

Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: Lloyd De France on 22/05/2010 00:30:03

Title: If atoms are mostly empty space, why do things feel hard?
Post by: Lloyd De France on 22/05/2010 00:30:03

Lloyd De France  asked the Naked Scientists:
   
Since most of the space in an atom is empty, why is it that objects in the macro world feel solid?
 
Lloyd De France
New York, New York, USA

What do you think?

Title: If atoms are mostly empty space, why do things feel hard?
Post by: Farsight on 22/05/2010 13:28:31

Because of electromagnetic force. It's rather like trying to push two very strong magnets together. It's hard, and it feels hard. 

Title: If atoms are mostly empty space, why do things feel hard?
Post by: Murchie85 on 23/05/2010 23:41:15

I have considered that also, try and explain this then. How can we describe sensations in terms of the em force? How some things feel hard, soft, painfull etc?

Title: If atoms are mostly empty space, why do things feel hard?
Post by: Soul Surfer on 24/05/2010 08:31:08

Absolutely everything you experience other than the gravitational field of the earth is related to the electromagnetic force.  Thats the way the universe works on our scale.  Atoms tend to stick together by various means using the electromagnetic force and the way they stick together (chemistry)  produces everything else.

Title: If atoms are mostly empty space, why do things feel hard?
Post by: daveshorts on 25/05/2010 11:15:48

We are made up of charged objects, electrons and nuclei, and therefor how much space there is in an atom is largely immaterial when we touch a surface made of that material, what is important is the effect that the surface has on the atoms of your hand.

If you have ever played with very strong magnets and tried to push two north poles together, the magnets are not touching but you still can't move them together. Now imagine 2 surfaces made up of thousands of immensely strong N poles of magnets with large gaps in between. You can't push the surfaces together despite the huge amounts of space. If you were billions of times bigger than the space between the magnets you would think the surface was solid.

In real materials the forces are electrostatic, and far stronger than the magnets.

 If your hand distorts before the material then the material feels hard, if the material distorts before your hand then the material feels soft