If atoms are mostly empty space, then how do we appear solid to one another?

Answer 1

Great question. The illusion of solidity has everything to with electrons. As you probably know, like-polarities repel each other: The north end of a magnet repels the north end of another magnet, and the south repels the south, likewise. Magnetism is an expression of the same forces that are at the core of atomic relationships- protons have a positive charge, and they repel other protons. Electrons have a negative charge and, likewise, repel other electrons. Now you probably already know that the outside of all atoms is what scientist refer to as the "electron cloud." This is a cloud of negative charge that is created by the presence of electrons that are "orbiting" the nucleus. So then, when two atoms are squeezed together, their individual electron clouds, both having a negative charge, repel each other and won't allow one atom to pass through another. This is why your finger will not go through a table or a wall, and it is the only reason!

The force with which the electron cloud resists being pentrated is directly proportionate to the distance between two atoms. In english, this means that if you push twice as hard on the table, there is twice as much "pressure," or resistance between all of the atoms involved.

Now, the really cool question to ask is "Is it possible to 'defeat' the electrons so that atoms could pass through each other without any resistance or solidity at all?" And the answer is yes! It is possible for atoms to be squezzed so incredibly hard that they lose all ability to resist one another, and they become what scientists call a superfluid state. A neutron star is the best real-world example of a superfuid- where the atoms are squezzed beyond belief, and you could pass right through them without any interaction at all. The gravity on a neutron star is so strong though, you'd get squished into a superfluid yourself if you tried it.

Answer 2

An atomic nucleus is about 1/100,000 of the 'size' of an atom. The 'size' of an atom is usually taken to be the radius of the valence electron cloud, or more precisely electron probability distribution. While the individual constituents of a atom are small and occupy an negligible volume, the electromagnetic forces holding the atom together are strong, occupy the entire volume of the atom and extend into surrounding space. Atoms in a solid are held together by strong electromagnetic forces. The notion of solid is actually a measure of the force required to displace atoms, or to disrupt the strong forces holding atoms together.

Answer 3

If you look at a laser printed photograph under a hobby microscope (How dare you infer that I am a dork for knowing this) it looks like mostly white area. It is a series of dots that look like a picture, but when viewed with the eye it looks solid.

The same principle would apply to atoms, except light waves are much to large to see individual atoms. They cannot "fit" through the empty space.

Answer 4

While they may be mostly empty space, they can, nonetheless, reflect light in the spectrum that our eyes can detect. Anything that does not allow light to pass through appears solid to our eyes.

If you're a neutrino, or any elementary particle that weakly interacts with other particles, atoms mean nothing to you and you pass through like they weren't there.

Answer 5

First of all atoms are very small, and have qualaties that at that level work differntly, aka quantum physics. So we appear solid because in our fibers, and cells we do not have random atoms with large spaces inbetween them, but we have them compacted together, with strong molecular fields, that keep them in place.... actually you would have to be able to differnece from say your bone strucuture solid... to say blood a liquid, and the composition of those structures.

Answer 6

Atoms are indeed mostly empty space, but that space is sub-microscopic. Think about it :)

Answer 7

When you see a beach from an aircraft it looks solid, it's only when you get up close that you can see the sand particles.

As for why can't you see through us, trees in a forest can be quite far apart, but it's not long before your view is totally blocked.

Answer 8

Because molecules of solids are locked into position relative to each other, so they don't move and other solids will bounce off of them

Answer 9

Two bodies can't pass through one another because the electrons in e.g. your hand and the table repulse each other when you try to put them together and squeeze them one past another

Answer 10

Glueballs!