Questions tagged [metals]
559 questions
304
votes
10 answers
Why don't metals bond when touched together?
It is my understanding that metals are a crystal lattice of ions, held together by delocalized electrons, which move freely through the lattice (and conduct electricity, heat, etc.). If two pieces of the same metal are touched together, why don't…
jcw
- 2,701
132
votes
4 answers
Why can I touch aluminum foil in the oven and not get burned?
I cook frequently with aluminum foil as a cover in the oven. When it's time to remove the foil and cook uncovered, I find I can handle it with my bare hands, and it's barely warm. What are the physics for this? Does it have something to do with the…
Jason P Sallinger
- 1,315
126
votes
7 answers
Why are most metals gray/silver?
Why do most metals (iron, tin, aluminum, lead, zinc, tungsten, nickel, etc.) appear silver or gray? What makes copper and gold have different colors? What atomic characteristics determine the color?
Ali Abbasinasab
- 1,869
102
votes
11 answers
If I pull a metal bar for long enough with a constant small force, will it eventually break?
Let's say I have a strong metal bar. I pull it apart with a very small constant force -- obviously it doesn't break. However, this would disturb the internal configuration. If I let go, then eventually the internal configuration would return to what…
94
votes
7 answers
Why do metals only glow red, yellow and white and not through the full range of the spectrum?
Why don't metals glow from red to yellow to green to blue etc.? Why only red, then yellow and then white? Shouldn't all wavelengths be emitted one by one as the temperature of the metal increases? If some metals do glow at with different colours,…
Dieblitzen
- 1,697
88
votes
8 answers
Will a hole cut into a metal disk expand or shrink when the disc is heated?
Take a metal disc and cut a small, circular hole in the center. When you heat the whole thing, will the hole's diameter increase or decrease? and why? What will happen to the diameter of disc?
jojo
- 897
58
votes
7 answers
In electrostatics, why the electric field inside a conductor is zero?
In electromagnetism books, such as Griffiths or the like, when they talk about the properties of conductors in case of electrostatics they say that the electric field inside a conductor is zero. I have 2 questions: We know that conductors (metallic)…
Revo
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52
votes
2 answers
Why are gold mirrors yellow?
Why are golden mirrors yellow? Do they add a yellow component to the spectrum or absorb non-yellow components? If they absorb, then why are they used in telescopes being imperfect? If they add a yellow component, then where do they take energy for…
Dims
- 1,772
35
votes
10 answers
Are there physical properties that can be used to differentiate stainless steel from copper in a home environment?
So the backstory is that I purchased a reusable drinking straw that is copper coloured, but is advertised to be stainless steel. That got me thinking about whether I could be sure it was one or the other without having access to a laboratory. I saw…
Kolichikov
- 475
35
votes
1 answer
Was Titanic's captain's decision correct?
I just saw a documentary on Titanic. Someone in that documentary told Captain Smith "Shall we close the water tight doors, sir?" and the Captain replied "No, let it be open. Let the water be distributed uniformly throughout ship, so that we could…
Amit Joki
- 669
34
votes
3 answers
What are some dense elements I can use for a demonstration?
I'm musing about how to give students an intuitive feeling about density by letting them lift a same sized volume of different materials, e.g. 1 liter of water, a $10 {\times} 10 {\times} 10 \, \mathrm{cm}^3$ cube of iron, lead etc. So far, the…
Jens
- 3,779
28
votes
2 answers
What is the physics behind how welding works?
Why does putting the two metals to be welded into contact with one another in the liquid phase and then congealing (returning back to the solid state) make them stick together? why doesn't just touching two solid metal blocks together weld them…
Geremia
- 2,527
27
votes
6 answers
Why do metals have free electrons?
Throughout my highschool classes, I have been made to learn that metals have free electrons that's why they are able to conduct electricity.. But I never understood why. Is that related to metallic bonding... Correct me if I am wrong but even if…
Chahak
- 488
26
votes
1 answer
Does the Mott insulator exist?
The Mott insulator is a system that, due to strong electron-electron interactions, is an insulator but is expected to be a metal by formal charge counting of electrons in the unit cell. Often, the Mott insulator is defined to be the ground state of…
KF Gauss
- 8,275
22
votes
3 answers
How is silver a better conductor than platinum?
Based on my understanding, platinum should be a better conductor than silver. Here's my reasoning and assumptions. An atom's ability to conduct is based on the amount of energy required to displace electrons from it. The energy required is based…
gregsaab
- 215