Why do cars crash? (Instead of passing through each other)

[Kenneth Boon Faker]

If everything is made of atoms, and if atoms have so much empty space inside them - and if the building blocks of atoms are made up of wave-like particles that aren't solid (strictly speaking) - then why do cars crash and billiard balls bounce off each other, as opposed to passing through each other?

I think it's to do with the wavelength of physical objects. But would it be possible for someone to explain it in more detail in layman's terms without too much technical language please? Thanks

 

[ZapperZ]

Without even going into the consideration of wavefunction, you should already know that an atom is composed of an electron “cloud” surrounding a nucleus. When another atom comes close, the electron clouds of the two atoms encounter each other first. So already, at the very naive and simplistic level, you should be able to have an idea why they can’t simply pass through one another that easily, shouldn’t you?

Zz.

 

[Nugatory]

I think it's to do with the wavelength of physical objects.

No. But perhaps the first question you should be asking yourself is what makes a solid object incompressible?

 

[sophiecentaur]

I think it's to do with the wavelength of physical objects.

The 'wavelength' idea only applies to quantum objects (particles). The jokes about not getting through a doorway etc are not really valid.

 

[Dale]

if atoms have so much empty space inside them

I never like this pop science trope. The space inside an atom is completely filled with fields, and fairly intense fields at that.

 

[Kenneth Boon Faker]

Without even going into the consideration of wavefunction, you should already know that an atom is composed of an electron “cloud” surrounding a nucleus. When another atom comes close, the electron clouds of the two atoms encounter each other first. So already, at the very naive and simplistic level, you should be able to have an idea why they can’t simply pass through one another that easily, shouldn’t you?

Thanks Zz. So is the answer primarily the force of the electron field that prevents objects like cars and billiard balls passing through each other?

 

[ZapperZ]

Thanks Zz. So is the answer primarily the force of the electron field that prevents objects like cars and billiard balls passing through each other?

To be more general, it is the electromagnetic forces (in this case, I'm using the example of repulsive forces between the electron clouds).

However, please note that I stressed that this is a very simplistic and naive picture. My explanation does not explain why "bonding" occurs between atoms, i.e. if each electron cloud repels one another, then why can 2 or more atoms form molecules?

Still, at the elementary level, the explanation is a good starting point.

Zz.

 

[sophiecentaur]

I never like this pop science trope. The space inside an atom is completely filled with fields, and fairly intense fields at that.

The Neutron view of an atom is a bit different though. It would 'see' pretty much an empty space with a little massive lump in the middle. Same for a gamma ray picture, I think.
But three whole ideas together is probably a bit much for Pop Science.

 

[Kenneth Boon Faker]

To be more general, it is the electromagnetic forces (in this case, I'm using the example of repulsive forces between the electron clouds).

Thanks ZZ. That is sufficient for me. I'm just learning, and I'm interested in how the world works. But the technical language and complex maths formulas often go over my head

 

[Khashishi]

To be more general, it is the electromagnetic forces (in this case, I'm using the example of repulsive forces between the electron clouds).

I think it has more to do with Pauli exclusion principle than the electromagnetic force.

Matter is made up of fermions, which are not allowed to overlap the same state. So, two electrons can't occupy the same position, momentum, and spin. A solid object like a car is made up of molecules, in which there are many electrons which are more or less packed into the lowest energy state within the confines of the solid object. The lowest energy state for the electrons is already filled up, so there isn't room for two cars to be in the same place. Trying to push two cars into the same place will result in the molecules being forced into higher energy states, and the materials that make up the cars will cease to be the same as the original materials. i.e., the cars will be destroyed.

It's probably more accurate to think of a solid material like metal as mostly full, rather than mostly empty.

 

[ZapperZ]

I think it has more to do with Pauli exclusion principle than the electromagnetic force.

Matter is made up of fermions, which are not allowed to overlap the same state. So, two electrons can't occupy the same position, momentum, and spin. A solid object like a car is made up of molecules, in which there are many electrons which are more or less packed into the lowest energy state within the confines of the solid object. The lowest energy state for the electrons is already filled up, so there isn't room for two cars to be in the same place. Trying to push two cars into the same place will result in the molecules being forced into higher energy states, and the materials that make up the cars will cease to be the same as the original materials. i.e., the cars will be destroyed.

It's probably more accurate to think of a solid material like metal as mostly full, rather than mostly empty.

If you read my replies, I made sure I qualified them as being a simplistic explanation.

There ARE localized onsite repulsive forces. But as I've stated already, such repulsive forces do not explain many other observations that happen when two atoms overlap their electron clouds. I used the simplistic electrostatic forces based on what I perceived the OP could understand.

Zz.

 

[ryan liberty]

The reason we don't just pass through things is electromagnetic repulsion. Coulomb's law talks about how same charges repel, the electron orbital cloud repels other atoms from actually touching. It is the same force that makes two magnets of the same charge resist being to close.

 

[Khashishi]

The reason we don't just pass through things is electromagnetic repulsion. Coulomb's law talks about how same charges repel, the electron orbital cloud repels other atoms from actually touching. It is the same force that makes two magnets of the same charge resist being to close.

Magnets don't have charge. The electric force and magnetic force are unified, but it is incorrect to apply Coulomb's law to magnets.

 

[ryan liberty]

Magnets don't have charge. The electric force and magnetic force are unified, but it is incorrect to apply Coulomb's law to magnets.

I suppose I should have been more specific, however a magnetic field is a projection caused by the movement of charged fluid. What I meant was that Coulomb's law applies to charged particles instead of magnets, I was speaking to generally.

 

[ZapperZ]

I suppose I should have been more specific, however a magnetic field is a projection caused by the movement of charged fluid. What I meant was that Coulomb's law applies to charged particles instead of magnets, I was speaking to generally.

What is a "projection"?

Zz.