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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85 views

Martian space elevator from the vulcano Olympus Mon to the moon Phobos?

In my fascinating imagination, I am seeing a space elevator from the vulcano Olympus Mon to the moon Phobos. Phobos also seems to keep spaceships - while a smaller shuttle attaches itself to the ...
3
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3answers
2k views

Space Elevator on Mars with Today's Technology Possible?

I know it's not possible with Earth today, but With today's level of material science technology, would it be possible to make cable strong and light enough to make a space elevator system connecting ...
4
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7answers
256 views

Is it possible to cut harder material with a less hard material?

Is it possible to cut harder material with a less hard material - for example cut a steel rod with iron blade ?
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2answers
734 views

What properties would the ideal material for spacecraft construction possess?

Assuming we develop the capability to send a robot to study Gliese 518, or any of the Earth-like planets discovered in the neighbourhood; the spacecraft would need to travel through the Solar System ...
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3answers
162 views

Are there materials that get softer with temperature decrease?

Could be there material that begins melting/softening when it's temperature is lowered? I would say no, but I've seen enough physics to know that not always life is so easy. Moreover I think I've ...
13
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2answers
690 views

How is graphene a 2D substance?

How is graphene a 2D substance? It has length, width and some thickness to it, else it would be invisible. Why is it considered a 2D substance?
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0answers
15 views

What are the factors affecting transparency and color of a substance [duplicate]

What is the reason behind visual properties like color and transparency of different substances? I have always heard that the structure of the substance is responsible for these properties. I always ...
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1answer
18 views

Material for moisture moderation

Do you know of any material that can moderate the level of moisture of its local environment? Example: if the desired moisture level is 30% and the local environment of the material is at 6% the ...
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0answers
17 views

Material that can provide soft flexibility, while maintaining conduction “accuracy”

I hope material search may be valid here. Is there a material that can be shaped as a few millimeters thick sheet, that can be placed on top a touch surface (e.g. iOS/Android tablet, Wacom drawing ...
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2answers
310 views

Why is steel-reinforced concrete stronger than ordinary concrete?

Is it only because steel has higher elasticity? What other factors are involved?
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0answers
52 views

What is the yield strength of a bar of different cross sections?

Will the yield strength of the combination will be same as that of the rod of uniform cross section?
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0answers
16 views

What are some structures which minimize surface stress upon expansion

Intro I am currently researching into a problem involving the cyclical expansion and contraction of a 3 layered structure comprised of an internal metal encased by another metal encased in an outer ...
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1answer
302 views

How many molecules rub off when I press a key?

I have a lot of questions below but my overarching questions are: Do surfaces rubbing lightly together always strip molecules off of each other? and How can we model that? Clearly the answer to the ...
2
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1answer
76 views

Demagnetisation by throwing a magnet

I tried to answer this question in a book about electrodynamics: How to demagnetise a permanent magnet, ie. described by $ D_T$ change into described by (0,0) I figured out about heating it up ...
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4answers
2k views

Is one way glass possible?

I am not talking about mirrors, just a plain window made of glass like material. Would it be possible to allow light pass only in one direction but not the other?
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1answer
296 views

If atoms have specific energy levels, why do opaque solids absorb all visible light, not just some? [duplicate]

Here's my question: if atoms have well defined energy levels and those differences correspond to the frequencies of light that can be absorbed, how is it that opaque objects absorb all or most visible ...
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0answers
61 views

Pearlite or spheroidite?

If steel alloy having either pearlitic or bainitic microstructures is heated to, and left at, a temperature below the eutectoid for a sufficiently long period of time (e.g.24hr), spheroidite will ...
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0answers
316 views

How hard is ice? [closed]

I know that there are many different types of ice and many ways for ice to form but I want to know about ice that a human might typically encounter, i.e. from a freezer or a sub-zero environment ...
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1answer
167 views

Question about supercooling

During the cooling of a liquid, if no impurity of site of nuclearation, an appreciable solidification will begin only after the temperature has been lowered to below the equilibrium solidification (or ...
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0answers
62 views

How can a paper battery behave like a capacitor?

I was trying to understand how paper batteries work and came across some explanations saying that the paper battery can also behave like a supercapacitor on account of its ability to discharge and to ...
3
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4answers
190 views

Surface area of glass (or general material) and strength

How does the surface area of a piece of glass (or any general material; sapphire isn't technically glass) correlate with strength? Strength as in resistance to pressure concentrated at a small point? ...
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0answers
47 views

Color of cementite

I have a question about micrograph of steel. In eutectoid steel, the pearlite exists as grains, within each colony the layers are oriented in essentially the same direction, which varies from one ...
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1answer
97 views

Why can't a dislocation terminate in the bulk?

We are told that they can only terminate on surfaces, grain boundaries or other dislocations but we are not told why they can't terminate inside the crystal.
3
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0answers
94 views

A physicists perspective on a material science/engineering problem

I am looking into some research that involves engineering and material science. As a physicists I wondered what other physicists would think of this problem and how they would approach it. Much of the ...
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1answer
57 views

intermetallics and solid solution

For some systems, discrete intermediate compounds rather than solid solutions may be found on the phase diagram, and these compounds have distinct chemical formulas; for metal–metal systems, they are ...
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0answers
53 views

Graphene conductor? [closed]

I was thinking if we had a a busbar that can carry massive amounts of current(since its resistance is $0.9\, \mathrm{\mu \Omega}$), and it's weight is $15\, \mathrm{kg}$, I assume if graphene would be ...
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1answer
74 views

A question about residual stress

Shot peening is a process of inducing residual compressive stress on the surface layer of metal parts. When shooting particles are colliding on the surface of metal there is a compressive stress. My ...
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2answers
222 views

Where I can find information about how helium gas diffuses through different polymer materials

I need more experimental information about helium gas diffusion in solid materials such as different plastics, metals, ceramics etc. For example I am scientifically curious about what is the polymer ...
2
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1answer
43 views

What is the meaning of $\%E$ on a graph?

I'm reading the book The New Science of Strong Materials by J.E. Gordon. He writes when we plotted (...) breaking strain, against thickness, we found it did not matter what the whiskers were made ...
2
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1answer
55 views

Where will a board break when weight is added to the end?

If you have a board, say a standard 2x4 of finite length, where one end is fixed in a cement wall and the other end is free, and you begin adding weight to the free end until it breaks, where will the ...
7
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4answers
491 views

How does water carve rock?

How does water carve rock? And more generally, how does a soft material carve a hard material? Obviously it happens, but is it a continual process (every drop of soft water carries away a minute ...
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0answers
11 views

Determining porosity in metals

I am in need of a book (preferably) or other reference material which would help technicians determine whether porosity exists in the fracture face of a tensile test bar for a variety of different ...
1
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1answer
54 views

Is there a textile like material that can act as a spring? [closed]

Imagine some sort of textile (as in very light, not metallic) that is tightly rolled up, can be easily unrolled by applying some force (i.e pulling it) but when released will eventually return to it's ...
4
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2answers
46 views

What keeps objects made of the same plastic apart?

I have two objects here which are made of the same plastic. When I hold them together, they remain separate objects: I can pull them apart with no resistance. How does each atom/molecule “know” which ...
10
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1answer
287 views

Why does finely cut paper curl?

When paper is cut to a small width, it curls up like this. Why does this happen?
3
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2answers
98 views

Not-so-hot black shirt

As it is getting warmer here by the minute I was asking myself: Are there materials, that are black (in th visible range) but reflect (most) invisible light? Furthermore, I asked myself what ...
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3answers
113 views

Does Mohs scale of mineral hardness always hold?

According to Wikipedia's article on the Mohs scale of mineral hardness, materials / minerals with a higher rating cannot be "visibly" scratched by materials with a lower rating. It goes on to admit ...
4
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1answer
378 views

Why is powdered sugar less dense than granulated sugar?

The density of powdered sugar is about 20% lower than that of granulated sugar. There is small composition difference between the two - about 3% cornstarch and 0.5% water in powdered sugar, but that's ...
3
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2answers
85 views

Can zinc nitride be used as light emitting material?

I cannot manage to find any journal papers about the applicability of zinc nitride as active layer of an light emitting diode (LED). But certain papers got mention that zinc nitride with a direct ...
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3answers
136 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 ...
2
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3answers
315 views

Which is stronger, wire rope or chain?

Assume they are the same material with the same weight, which is stronger?
3
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1answer
79 views

What keeps objects made of gold apart? [duplicate]

I was told the following basic facts: Objects made of the same metal don’t fuse in the atmosphere because they form an oxide layer. They do fuse in space. Gold doesn’t oxidize. Yet, gold nuggets ...
2
votes
1answer
100 views

Does the Night Mode of the screen display (LCD) save more energy?

In some cases, we can enable the Night Mode (reversing the bright and dark color of the display; such as White Text, Black Background) for the screen display. LCD(Liquid-crystal display) seems to be ...
1
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1answer
445 views

What is tricritical point?

Critical point is the transition temperature of a second order phase transition. But what does tricritical point mean? WIki says that a tricritical point is a point in the phase diagram of a system at ...
6
votes
1answer
144 views

Material implementations of the holographic principle

I'm afraid this question is a little too open-ended, but bear with me while I find a better formulation. carbon allotropes (like fullerenes and graphene) are regular patterned. Conduction bands of ...
1
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1answer
31 views

Glass Hardness and Pressure

How is glass hardness defined? I understand that ordinary kitchen knives cannot scratch most toughened glass, such as the ones found on cell phones. However (I once tried) - with enough pressure, one ...
5
votes
3answers
401 views

What makes materials hard and strong?

This is something I have wondered for a long time. Why are some materials like steel, diamond, and even light materials like graphene stronger than others? Is it due to the strength of the ...
3
votes
2answers
135 views

Can Aluminium be softened

I have an aluminium baking plate that I did put in a very hot oven and now it is soft, so I can bend it or almost roll it up. Why?
1
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1answer
194 views

Reducing Friction between 2 abs plastic bodies [closed]

Here at the company we've been working on a new product, and it will more than a few times a day and with a considerable force, slide on a plastic surface, being itself, another plastic body, roughly ...
19
votes
3answers
5k views

Why can't a piece of paper (of non-zero thickness) be folded more than $N$ times?

Updated: In order to fold anything in half, it must be $\pi$ times longer than its thickness, and that depending on how something is folded, the amount its length decreases with each fold differs. ...