Ask a physicist anything. (4)

[Supreme]

I have a question for a physicist: how far do you feel chemistry contributed to physics? And which do you feel is more important?

(My old physics teacher always went on about how rubbish chemistry was and how far superior physics was. Amusing.)

 

[Cabal]

I have a question for a physicist: how far do you feel chemistry contributed to physics? And which do you feel is more important?

(My old physics teacher always went on about how rubbish chemistry was and how far superior physics was. Amusing.)

I'd say if it wasn't for chemistry, modern physics wouldn't exist. Certainly my field (quantum optics/atomic physics) all grew out of thermodynamics and stoichiometry.

I remember a harsh lesson during my second year of my undergrad, where we were all complaining about having to solve the Schrodinger equation for the hydrogen atom, and then the dual major students (physics and chem) just rolled their eyes and showed us the stuff they were having to learn in their chem classes about resonance hybrid structures, and we were struggling with a lone 1s orbital.

Chemistry is definitely a subject I regret not being able to study more of.

That said, chemists are total electron-obsessives and nowhere near as cool as physicists

 

[Wiccan_Child]

I have a question for a physicist: how far do you feel chemistry contributed to physics? And which do you feel is more important?

(My old physics teacher always went on about how rubbish chemistry was and how far superior physics was. Amusing.)

Well, it is superior

Back in the day, physics and chemistry studied different things: physics was the study of motion and forces, chemistry was the study of what makes up matter. We've now got such a complete understanding of the Classical world that physics can even explain the chemical world - thus, physics is the bedrock of modern chemistry.
One the one hand, chemistry is just the study of electron transfer, while physics is the study of the underpinning forces and overarching super-structures. On the other, trying to apply pure physics to chemistry is bloody hard, so kudos to the chemists

 

[catzrfluffy]

What's the coolest prank you've pulled?

 

[Steffenfield]

Please take this very simple, basic test as fast as possible without cheating.....
Intuitor Basic Physics Savvy Quiz

Then go ahead and post your scores.

And no, I'm not telling anyone my final score was 40% so forget about even asking me.

 

[pgp_protector]

Please take this very simple, basic test as fast as possible without cheating.....
Intuitor Basic Physics Savvy Quiz

Then go ahead and post your scores.

And no, I'm not telling anyone my final score was 40% so forget about even asking me.

Your Total Score is 70 %

 

[Steffenfield]

I was expecting better from you protector.

I don't think you applied yourself.

 

[pgp_protector]

I was expecting better from you protector.

I don't think you applied yourself.

sorry, long day & watching a movie to boot

 

[shinbits]

Please take this very simple, basic test as fast as possible without cheating.....
Intuitor Basic Physics Savvy Quiz

Then go ahead and post your scores.

And no, I'm not telling anyone my final score was 40% so forget about even asking me.

Your Total Score is 55 % ​

 

[Cabal]

Woot, 95%.

Although they do seem a bit fixated with Newton's 3rd law.

 

[SithDoughnut]

GSCE Science and the occasional reading of books got me 70% on that test. Looking at the explanations, it would appear that most of the wrong answer are me forgetting the exact definitions of certain words.

Also, a random question. If I took the Earth and compressed it to the size of, say, the Moon, would the gravitational force be exactly the same? In other words, is it only mass that affects gravity?

 

[Steffenfield]

Woot, 95%.

Although they do seem a bit fixated with Newton's 3rd law.

Fire up chief!

Good for you!

Can I please touch your brain.

 

[Cabal]

Fire up chief!

Good for you!

Can I please touch your brain.

It should have been 97.5%, but I misread force as pressure in one of the questions. In my defence, I've been awake all night.

 

[Cabal]

GSCE Science and the occasional reading of books got me 70% on that test. Looking at the explanations, it would appear that most of the wrong answer are me forgetting the exact definitions of certain words.

Also, a random question. If I took the Earth and compressed it to the size of, say, the Moon, would the gravitational force be exactly the same? In other words, is it only mass that affects gravity?

Yup, only the mass of the interacting objects and their separation.

 

[Gracchus]

I would have done better had they not redefined the definition of the milliliter in 1964. (I remembered that in 1956 it was not exactly 1 cc.) I missed that bit. And it has been over 40 years since I took either chemistry or physics. So: 80%

 

[Assyrian]

Also, a random question. If I took the Earth and compressed it to the size of, say, the Moon, would the gravitational force be exactly the same? In other words, is it only mass that affects gravity?

Mass and distance.

So the question is, is the gravitational force the same... where? If you compressed the earth (don't try this a home) but stayed the same distance from the center of the earth, so while the earth goes from a radius of 6371 km down to 1738 km, your lab is now hovering 4633 km above the new surface, or if you carried out the experiment from the safety of an orbital platform, there would not be any change to the gravity. However if your lab stayed on the surface of the earth, the radius of the earth is about 1/4 of what it was, the force of gravity is inversely proportional to the square of the distance, and would be 16 times stronger. (This is of course assuming all the mass was acting from the centre of the earth, but as all the distances between you and the atoms making up the earth will be divided by 4, the result will be the same.)

 

[SithDoughnut]

Never mind, I just read Assyrian's post.

 

[Wiccan_Child]

Please take this very simple, basic test as fast as possible without cheating.....
Intuitor Basic Physics Savvy Quiz

Then go ahead and post your scores.

And no, I'm not telling anyone my final score was 40% so forget about even asking me.

95%!

I dispute the two I got wrong

"6) If there were no energy losses due to friction or unwanted heat transfer, an internal combustion engine could be built for an automobile which would be capable of converting 100% of the combustion energy in gasoline into energy used for moving the car. (Assume 100% of the fuel is burned during combustion.) "

With no friction or unwanted heat transfer, it's quite possible... yet the answer is false! Boo.

"8) Energy is the ability to do work. In other words, if Ben needed 1000 joules of energy to move a box 5 meters across the floor it would make no difference whether he had 1000 joules of thermal energy or the same amount of mechanical energy. He could still do the work required to get the job done."

Energy is energy. If he 'had' 1000 joules of thermal energy, it's his to use as he wishes. Build a turbine and off you go. Boo.

 

[Wiccan_Child]

GSCE Science and the occasional reading of books got me 70% on that test. Looking at the explanations, it would appear that most of the wrong answer are me forgetting the exact definitions of certain words.

Also, a random question. If I took the Earth and compressed it to the size of, say, the Moon, would the gravitational force be exactly the same? In other words, is it only mass that affects gravity?

They wouldn't be exactly the same, since the Moon is made of the Earth's crust, and is suspiciously lacking in any of the heavier elements that make up the Earth's deeper layers. So the Earth would be heavier, and, thus, have a greater gravitational force.

The Earth already has a greater gravitational force on its surface than the Moon (about three times greater), so just think what happens if you squish it even denser

 

[SithDoughnut]

They wouldn't be exactly the same, since the Moon is made of the Earth's crust, and is suspiciously lacking in any of the heavier elements that make up the Earth's deeper layers. So the Earth would be heavier, and, thus, have a greater gravitational force.

The Earth already has a greater gravitational force on its surface than the Moon (about three times greater), so just think what happens if you squish it even denser

I know, that's why my question said "compressed to the size of the moon" not "turned into the moon".

I think I got my question answered anyway, but just to clarify - density has an effect on the gravitational pull, right?