Solids & Liquids can be compressed?

DaSilva

I was thought in school that Solids and Liquids couldn't be compressed, but I've now read that they can, and to be honest it makes sense that they can since the molecules are 99% (or whatever) space.

I'd like if this was confirmed though, and I also wonder why is it taught in school that they can't be compressed? I understand that it requires much more effort to compress solids or liquids than it requires for a gas, but still, what they are teaching is effectively wrong.

Princess Consuela Bananahammock

At Ten Past Four In The Monring...???!!!!

DaSilva

Ikky Poo2 wrote:

At Ten Past Four In The Monring...???!!!!

No work tomorow since I quit because I'm going away for the summer, and I am doing a small side job for somebody I know that needs to be done by Sunday which I'm a little behind on, and I was working on a little invention that is related in a sense to the topic.

ArphaRima

If I remember rightly the science/physics books open with a summary stating that solids and liquids are "assumed to be incompressible" for the purpose of simplicity. Thats all. It was to protect our fragile minds.
For the record its 10:30am here...

Tar.Aldarion

Of course they can be compressed. What you were taught was probably that they were not compressed significantly.
4:37.
Physics yay!

Son Goku

Yeah they can be compressed.
However if you ignore the fact that they can be compressed (particularly Liquids) you can solve the equations which govern their motion on a home pc.
If you don't ignore it, even a supercomputer can't solve the equations.

DaSilva

I assume when we compress a solid, that we are really doing is forcing the atoms closer to each other against the force (whatever its called). Let's just for the sake of simplicity say that 99% is the actual figure for the ammount of space in an atoms, can we then compress any solid (even if it takes massive ammounts of effort) to 1% of it's size?


Second Q.
When I hit something, for example my table here, I slam my hand down on it, when I do that, are the (wow I'm over my head) atoms in my hand, closer to the atoms in the table, than they usualy would be in a rested position (ie just my hand resting on the table). What Im wondering is, am I slightly really slightly compressing the table when I hit it? Or is there a treshold of force, that you must apply before it will begin to compress?

legologic

well things can only be compressed so far because of the stron and weak nuclear forces which are rediculously strong compared to gravit. The more you compress things the harder (significantly harder) it becomes to compress them more. For super compressed matter you could read up on neutron stars. Basically these are so compressed that electrons and protons have benn squished to form neutrons and the neutrons are all squashed together.

I'd answer your other question but gotta run. google newtons third law and hookes law for an aproxomate answer or i'm sure someone elso will provide one.

J

dudara

DaSilva wrote:

When I hit something, for example my table here, I slam my hand down on it, when I do that, are the (wow I'm over my head) atoms in my hand, closer to the atoms in the table, than they usualy would be in a rested position (ie just my hand resting on the table). What Im wondering is, am I slightly really slightly compressing the table when I hit it? Or is there a treshold of force, that you must apply before it will begin to compress?

Ever see the experiment where people walk on custard? Similar kind of principle

Hagar

DaSilva wrote:

I What Im wondering is, am I slightly really slightly compressing the table when I hit it?

The table may actually partially enter your hand.
I'm sure there is a very scientific name for this but as a layman I've always heard it referred to as a splinter.;)

legologic

^^electron tunneling

the reason we are 99% free space is because atoms are held in an arrangement by the strong and weak nuclear forces. Strong and weak forces are both actually rather strong. If you imagine that your hand is being held together by these forces and so is the table... when you slam down on it, tho' you may come a few femtometres closer (that is you slightly overcome the nuclear forces) atomically it's probably not very noticeable. If you look at the two appached pictures it's an approximation of what would most likely happen if you slammed a table (and had abnormally square hand and extremely large atoms in them).

I slam my hand down on it, when I do that, are the atoms in my hand, closer to the atoms in the table, than they usualy would be in a rested position

So essentially, to be pedantic... probably. On a microscopic level... no. on an atomic level... barely.

Capt'n Midnight

Solids can be compressed.

Plutonium depending on the state can be up to 19.1 g/cm3

An implosion can increase this by a factor of up to 5 !
(or maybe they mean the 16g/cm3 state to ~ 80g/cm3)

http://nuclearweaponarchive.org/Library/Implsion.html

RefulgentGnomon

Ever see the experiment where people walk on custard? Similar kind of principle

It is the custard powder, which is essentially cornflour. Google 'oobleck' for stuff about it being a solid and liquid at the same time. Try it out then - weird!