The study of how the properties of matter arise from its structure at all scales and of how processing can be used to modify those properties (often in pursuit of a specific application).

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6
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3answers
920 views

Why don't metals damp vibrations?

Fluid damps vibrations due to viscous dissipation. Does anyone has any insight on a molecular, microscopic level about the reasons that vibration damping of metals is negligible?
-1
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1answer
18 views

The existence Water nanoparticles [on hold]

Has anyone investigated the properties of water nanoparticles? If yes what are those? If not, why not?
0
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2answers
50 views

Why an impact exerts so much force?

If an object of velocity $v$ and mass $m$ moves towards a resting object of mass $M$, then if the object which is hit might break. Why? What is the reason that a collision has more power than a ...
0
votes
0answers
17 views

How does the shattering of an amorphous solid change in lower gravity?

This is a question that's been bothering me for a while. If I were to stand on the moon, holding a pane of glass, what would happen if I smashed it? Glass is an amorphous solid, which is why it is ...
14
votes
4answers
1k views

Are insulators and conductors arbitrary categories?

I have seen charts showing the transition from insulator to semi-conductor is at $10^{-8}~\frac{\text{S}}{\text{cm}}$ and between semi-conductor and conductor is $10^{3}~\frac{\text{S}}{\text{cm}}$. ...
0
votes
1answer
374 views

Malleability in metals

I am trying to understand malleability in metal as a result of the micro structure. I am focusing on the metals of antiquity (in order of decreased malleability): Gold, Silver, Copper, and Iron. While ...
0
votes
2answers
27 views

Reason behind heating the substrate in Pulsed Laser Deposition

Why do we need to supply a constant heat to the substrate while depositing thin films in Pulsed Laser Deposition technique?
1
vote
1answer
133 views

Energy conservation of permanent magnets engine

How to explain the fact that magnet can attract an object (apply a work W) without losing a (significant) part of its internal energy? How to apply the energy conservation principle? Please think to ...
1
vote
0answers
19 views

Mechanical properties crown cap [on hold]

What are the important mechanical properties to look at when designing a crown cork and why? Thank you in advance
1
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2answers
343 views

Do bifacial solar panels operate at lower temperature than normal solar panels?

Bifacial solar panels have a glass backplane instead of the usual aluminum and are designed to absorb and convert to electricity light incident on either face. Many manufacturers claim that their ...
0
votes
2answers
32 views

Can you dent a metal wall with a feather?

I know that theoretically you can only scratch a material with a harder material, but what about denting? While scratching a solid would seem to involve breaking bonds, denting a solid would ...
0
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0answers
30 views

How strong could a carbon nanotube be?

I was thinking about the limits of flywheel energy storage and wondered about carbon nanotubes. The amount of energy that can be stored per unit mass in a flywheel depends not on tensile strength but ...
4
votes
1answer
78 views

Why do headphones tangle themselves whereas shoe laces untie themselves?

Why do headphones tangle themselves whereas shoe laces untangle or untie themselves? Why aren't we using the phenomenon to create headphones that tangle less and shoe laces that untie less?
0
votes
0answers
5 views

Height of a point in a plane given a measure of luminance

Context Assume a left-hand rule coordinate system and X points right, Y points up, Z points out. I have a camera facing perpendicular to the X-Z plane in the negative Y direction. I have 4 ...
0
votes
1answer
32 views

Calculating the Coefficient of Restitution Based on two Objects

The coefficient of restitution is calculated based on the velocities of objects before and after a collision: $$C_R = -\frac{v_{2f} - v_{1f}}{v_{2i} - v_{1i}}$$ The coefficient of restitution tells ...
2
votes
2answers
3k views

Best Materials Science Introduction Book?

What would you suggest as a good introduction to materials science? (Prior usage and examples would be wonderful, my particular focus is neutron scattering). What I've Found So Far: Materials ...
1
vote
1answer
30 views

Tensile strength of a chain of electromagnets

I was having a discussion about the tensile strengths of various materials. Could something like a chain of electromagnets be made to have a tensile strength proportional to the power applied to it? ...
3
votes
2answers
88 views

in Science materials, what is difference b/w E and G?

I'm studying Science Materials on Callister's Materials Science and Engineering: An Introduction. I've never studied Mechanics (except for basic Physics courses), so I was wandering: when talking ...
-1
votes
2answers
45 views

Is there any material that can survive a nuke? [closed]

Is there a material known to man that I can tape to a Tsar-Bomba-yield nuclear warhead and find kilometers away after detonation? This question is quite similar but a nuclear explosion is quite ...
0
votes
0answers
31 views

Why should we use good conductors as electrodes of a capacitor?

I was asked if and why why should the electrodes of a capacitor should be good electrical conductors. It seemed obvious to me that if I want to form a Helmholtz double layer (because that's what ...
0
votes
2answers
402 views

does the thickness of a rubber sheet affect the tensile strength?

i'm really confused which thickness of rubber sheet i should choose. Does the thickness affect the tensile strength and elongation in any way? is there any relation between them? i would really ...
1
vote
2answers
194 views

What is the physical significance of the Curie constant?

What is the physical significance of the Curie constant? I understand it depends on the effective moment of the ion and hence must be some measure of it, but what is it exactly? Like some average ...
1
vote
1answer
150 views

What is blocking the magnetic field of this neodymium magnet?

I opened up my hard drive and pulled out (among other things) the top and bottom braces for the reading arm. Each bracket contains a really powerful neodymium affixed to its underside. When the ...
0
votes
2answers
42 views

What causes tensile stress to decrease after a material/wire reaches its ultimate tensile stress?

I was reading the AQA A Level Physics revision guide by Jim Bretihaupt, and in the Materials chapter in the section to do with plastic deformation, it says: Beyond the ultimate tensile stress, the ...
0
votes
1answer
24 views

Would a bullet damage a piece of metal the same as a pointy stick?

If you used a materials that would offer zero bending or dulling (the bullet/ pointy stick), would a 10 g bullet traveling at 1000 m/s with a surface area of 1 mm squared damage a piece of metal the ...
0
votes
0answers
8 views

Does the rate of pressure change matter when measuring the strength of a closed container?

If I had a container that could hold 100 psi, and I increased the pressure to 100 psi instantly would I cause any excess stress on the container, or would it not make a difference from doing it over ...
0
votes
0answers
82 views

Qualitative understanding of excess heat capacity in ferroics

I'm looking to understand what an excess heat capacity in a ferroelectric (FE) can correspond to qualitatively. Typically one starts with a Landau expansion of the free energy if you want to study the ...
5
votes
1answer
267 views

Force problem related to adhesive and bonding

I have two PCBs (printed circuit board), and they are glued by adhesives, as show in the pictures. And the location of the adhesives are indicated on the picture (please notice that NO adhesive is ...
0
votes
1answer
21 views

Material that reflects only a certain polarization?

Do materials exist that (significantly) reflect one polarisation of light and transmit all others?
0
votes
0answers
16 views

Copper vs Tungsten (Diffusion)

I've been studying on how to compare the activation energy for (void-) diffusivity of Copper versus Tungsten. I ended up finding $E_a[cu] = 1.1[eV]$ and $E_a[W] = 5.2[eV]$ in literature where the ...
0
votes
1answer
34 views

How to reduce size of bracelets using physics?

My mom has a set of bangles (bracelets) made of gold like the ones shown in the picture. Problem is the size (diameter) of these bangles is a bit more than required. If she goes to a goldsmith he cuts ...
1
vote
3answers
191 views

What can justify the decrease of the electrical conductivity with the increase of light intensity?

I have currently been working with a sample that "appears to" decrease its resistance when I cover it and protect it from light. Basically it presents the opposite behaviour of a photoresistor. What ...
0
votes
1answer
221 views

Fundamental frequency of a material and its Young's modulus

I wonder if there is a connection between fundamental frequency and Young's modulus of a material. For example, how to calculate the Young's modulus of a glass bar by knowing its frequency spectrum?
12
votes
1answer
225 views

Third-order susceptibilities of metals?

Can anyone point me to a source for measurements of the third-order nonlinear electric susceptibilities $\chi^{(3)}$ of various metals? Specifically in relation to the AC Kerr effect, so measurements ...
4
votes
1answer
376 views

What factors cause the velocity saturation to occur at different electric fields for different materials?

In semiconductors the velocity of carriers gets saturated after a certain value of electric field. In silicon it occurs at around $10^4 kV/cm$ and in GaAs at some other value. What factors are ...
6
votes
1answer
522 views

Semiconductor problem: how much Boron is required to establish a certain amount of charge carrier density

The problem description is as follows: Boron is used to dope 1 kg of germanium (Ge). How much boron (B) is required to establish a charge carrier density of 3.091 x 10^17 / cm^3. One mole of ...
7
votes
4answers
13k views

What common materials absorb most infrared light?

I'm competing in a simple robotics competition where most of the participants use reflected infrared light to detect their opponent. I'd like to make my own robot as difficult to see as possible. What ...
1
vote
1answer
118 views

What is difference between anisotropy and inhomogeinity of this type of composite material?

I am studying some types of composite materials having 2 phases - fibers and matrix. I have some questions and confusions. Any help is appreciated. The composite has fiber along length and I am ...
4
votes
2answers
89 views

Why nano indentation is used to test bulk material?

I am curious why nano indentation is used? I can understand when material size goes to micros or below, conventional hardening methods can become difficult to use. However many papers say that ...
0
votes
1answer
48 views

Is a laminated padlock really stronger than a solid one, and if so, why?

I used to think that the padlock design of using many layers of metal stacked to form the main body was a cost-cutting consideration. This was my assumption before I came across the idea that it was ...
7
votes
1answer
120 views

Invariant polynomials of the Landau theory of phase transitions (crystal symmetry?)

I'm convinced I'm missing something so obvious but here goes Typically, one can define something like a "general" expansion of an order parameter, ${\boldsymbol \Gamma}$, up to 6th order as follows ...
1
vote
1answer
52 views

When you push a stick will the end of it respond later than the beginning? Is so what is the fastest material and what forces are involved?

Normally when two people hold a long stick the receiving person would feel at the same time the stick moving when the first person gives the stick a push. But is that in reality exactly the case? ...
0
votes
3answers
44 views

Ozone elimination

I have a potential problem with airflow through a high voltage capacitively coupled RF discharge (in a tube) producing ozone. How can I remove ozone from the airflow? The use of liquids is not ...
19
votes
3answers
4k views

How does paper make sound when it is torn?

We know that from our experience when we tear up a piece of paper, we can hear a characteristic sound. What is the underlying mechanism behind it? What do the dominant frequencies (edit: I don't mean ...
1
vote
0answers
21 views

Armco iron B-H curves [closed]

I've been looking for B-H curves for Armco iron. I'd love to find one with good resolution. Does anyone know where you could acquire one? I've been looking in various Armco ingot supplieres but no ...
0
votes
1answer
38 views

Why can't we build a styrofoam 747?

What properties of materials explain why building the same structure at different scales requires materials of different densities and strengths? Consider an airliner, and flying models thereof at ...
3
votes
2answers
368 views

Does metal under low tension ever actually bend?

Let's assume something like a pair of tweezers, since that's strangely what led to this mental exercise. Does the metal ever actually permanently transform its shape? Stainless steel is fairly ...
0
votes
5answers
187 views

Is this a fundamentally relativistic phenomenon?

This question was inspired by some silliness in other threads but is independent of that silliness. Say that a train car sitting on a track is accelerated uniformly along its length if each point on ...
76
votes
9answers
14k views

Why does matter exist in 3 states (liquids, solid, gas)?

Why does matter on the earth exist in three states? Why cannot all matter exist in only one state (i.e. solid/liquid/gas)?
1
vote
0answers
9 views

Are nanorods stronger than bulk material? [closed]

For example, say you had a pillar of bulk material alongside an equal mass of nanorods in a sort of array of pillars. If you were to then apply increasing amounts of pressure to the top of them would ...