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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Calculate the weight a simple plank can support [closed]

I'd like to build a simple desk; just a single plank of wood (or a few side-by-side) with solid supports on each end of the desk. What I'm trying to figure out is how thick a plank I want to use for ...
18
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3answers
4k views

Roughly how many atoms thick is the layer of graphite left by a pencil writing on paper?

Actually I can't expand much as the question pretty much explains the query. I would be interested in the method of estimating an answer as well as a potential way to measure it experimentally. ...
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8answers
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Will a hole cut into a metal disk expand or shrink when the disc is heated?

Suppose you 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?
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1answer
321 views

Force curve associated with squeezing a worm-like chain (WLC) between two parallel plates

Let's say I have a polymer, of contour length $L_p$ and persistence length $P$, positioned between two parallel plates separated by a distance $z$. I slowly squeeze the plates together until only ...
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1answer
678 views

Is there any way to increase a rubber-bands lifetime?

Rubber-bands are simple, yet very useful. Old rubber bands(5 years?) get brittle? Why is that?
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0answers
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What is the cause of strain hardening and strain softening? [closed]

Why is it, that - if displayed in a strain/stress-diagram - the curve will at first be linear, and then change into a "curved shape", where it will first decrease again, and only later increase again? ...
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3answers
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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 ...
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2answers
1k views

What happen when a gas is being heated far beyond its boiling point?

let's say we pour some water to the Sun. Or boil water on 2000 degrees Celsius on Earth.
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1answer
2k views

Transparency of materials

Is transparency of material has something to do with inter- or intra-molecular bonding? E.g. both graphite and diamond are carbon, but graphite is opaque and diamond transparent.
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0answers
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What properties of certain plastics make them x-ray transparent? [closed]

I was blown away by the abundance of good info here, and I thought maybe you could help me out with this query. I am in the process of developing a product, and I need to find a clear plastic resin ...
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1answer
543 views

Paper stiffness

As piece of paper is folded and unfolded, the stiffness of the sheet may seem to be greatly increased. To those of you who don't recognise it: take a sheet of A4 paper, grasp one of the edges and ...
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2answers
678 views

If sound wave is going to hit any metals can it make that metal electrons into exited state?

What will happen when sound wave hits the metals with very high frequency can it make the electrons to exited state. If it happens then what will be the state of that metal
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0answers
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Inflating a balloon (expansion resistance)

I am doing a quick calculation on how to calculate the pressure needed to inflate a perfectly spherical balloon to a certain volume, however I have difficulties with the fact that the balloon (rubber) ...
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3answers
873 views

Can the speed of light become complex inside a metamaterial?

The speed of light in a material is defined as $c = \frac{1}{\sqrt{\epsilon \mu}}$. There are metamaterials with negative permittivity $\epsilon < 0$ and permeability $\mu < 0$ at the same time. ...
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3answers
1k views

Optimal technique to tear perforated paper along the perforation [closed]

My daughter's coloring book has perforated pages, so you can easily rip out the pages for easier coloring action. Great. Trouble is, the perforation isn't enough, and it's almost impossible to rip ...
1
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1answer
389 views

Extracting water out of silica gel [closed]

From my preliminary research I've learned that desiccants are a good (best?) method to absorb water from air. Assuming I'm using silica gel (or kitchen salt, or rice) then what is the best way to ...
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3answers
3k views

Why can one bend glass fiber?

Why can one bend glass fibers without breaking it, whereas glasses one comes across in real life is usually solid? Is there also a good high-school level explanation of this?
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3answers
382 views

Are we crystals?

Can we say that we are crystals because just like crystals we are made up of very small unit (cell) making up almost the same shape (our body) everywhere.
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3answers
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Which metals can cause magnetic interference (passively)?

I am developing an application that uses the magnetometer inside smart-phones to detect orientation w.r.t. the Earth's magnetic field. I have noticed that when the phone is held close to a metal ...
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1answer
134 views

Current Physical Applications of Elastic Fractals

Are there any known uses of modeling with elastic fractals in current physical applications? (Especially uses concerning with self-similarity)
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1answer
562 views

BCS theory, Richardson model and Superconductivity

I'm studying Richardson Model in second quantization. There are many initial points that I don't understand: We supposed that an attractive force between 2 electrons exists, due to electron-phonon ...
4
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2answers
975 views

Stress tensor in a cube with shear forces

I want to calculate stress matrix in a cube with two faces parallel to x axis and perpendicular to z axis (sorry I don't know how can I put a picture in this post). There are two force uniform ...
1
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4answers
415 views

Will tensile strength keep a cable from snapping indefinitely?

Trying to secure a wall hanging using magnets; me and a coworker came up with an interesting question: When the hanging is hung using 1 magnet, the weight of it causes it to quickly drag the ...
18
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3answers
4k 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. ...
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3answers
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Why are materials that are better at conducting electricity also proportionately better at conducting heat?

It seems like among the electrical conductors there's a relationship between the ability to conduct heat as well as electricity. Eg: Copper is better than aluminum at conducting both electricity and ...
21
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1answer
792 views

Why is tape so hard to rip when it is not broken, but so easy once there is the tiniest cut in it?

Question says it all. Ripping a piece of tape along the width is tough, stretches the tape, messes it up, etc, but if you put the tiniest nick at the top, it rips without any problems. Why is that?
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3answers
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What determines the color of a pure substance and is it possible to predict it?

I have always wondered why salt is white, water is clear and gold is, well, gold. What determines the color of a substance? Does it have something to do with the electrons? And is it possible to ...
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3answers
241 views

Material resistency to lasers beam

Keeping the average power constant, why some materials are more eager to be damaged by pulsed laser with respect of C.W. lasers, or viceversa? When i talk about pulsed lasers i think for examples of ...
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2answers
662 views

Mnemonics to remember various properties of materials

I'm trying to figure out how to remember that hardness: how resistant it is to deformation toughness: how resistant it is to brittle failures stress: force on a surface area strength: ability to ...