# Tag Info

2

You could think of this in terms equilibrium processes. The shower increases the partial pressure of water in air and that pushes the equilibrium of water condensing on the surface in the forward. There may also be some capillary action if the adsorbed water can form small liquid droplets. As more water seeps into the tissue the stress-strain properties of ...

0

"Perceived" is the operative word here. Perception is subjective and pressure is hard to perceive objectively without a measuring device. Hydrostatic pressure experienced by a body submersed to a height $h$ under water is given by: $p=p_0+\rho gh$, with $p_0$ atmospheric pressure, $\rho$ the density of the water and $g$ the gravitational acceleration ...

2

I think it is partially a perceptional problem. The pressure, i.e. force per area is depdendend on the depth of water in this case, and it doesn't matter much, if you are naked or if you wear waders. But if you wear waders, the pressure is implied on the surface of your clothes, not on your skin. Your clothes will now dent to give in to the pressure, until ...

2

In my experience, in brushes the strongest force acting on the water is the capillary force due to the surface tension in the liquid and the proximity of the hairs in the brush. Surface tension will cause the water to try to "wet" as much of the brush hair as possible - regardless of orientation. If there is excess water, such water will be pulled down by ...

0

You should let it hang downwards, otherwise the water will drip down onto the ferrule, which can eventually corrode it. There's pretty much no reason to leave them tip-up: in particular any "local pocket" of humid air is unlikely to be rising much rather than expanding outwards in all directions. If you are worried about the local pocket of humid air during ...

0

When high pressure is applying on a gas, it gets converted into liquid form. Similarly, if more pressure is applied to the liquid, force of attraction increases so that the liquid is converts into solid state. As the pressure increases the rate of crystallization also increases. i.e., the freezing point also increases.

1

Here is an interesting article that shows how water was frozen at high temperature under pressure http://www.azom.com/news.aspx?newsID=8016 Here is an extract Sandia Convert Water to Ice in Nanoseconds Published on March 19, 2007 at 1:15 AM Sandia’s huge Z machine, which generates temperatures hotter than the sun, has turned water to ice in nanoseconds. ...

2

The speaker causes the hose to vibrate, shaking it 24 times a second. To the naked eye this looks like something of a blur, but if your camera is also taking a shot every 24 seconds the video looks like the water is frozen in space, with just slight changes to the position of the drops. Adjust the frequency up slightly and the water appears to be falling ...

1

Water, like most liquids does indeed get more viscous as its temperature approaches freezing point. See the graph below, which I took from the "Engineering Toolbox" However, what's interesting about this curve is that it does not diverge as $T\to 0^\circ{\rm C}$. The reason is that a phase change really is for all effective purposes a discontinuous ...

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Pouillet's Law is valid in general, but the specific values of l and A depend in the shape and environment of the resistor. See https://www.academia.edu/1841457/The_Notion_of_Electrical_Resistance

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Both turbines and motors can be used to turn an electric generator which produces electric power. I will exclude electric motors for this short overview. Both turbine and motor work on an operating fluid, the so-called working fluid. A turbine is continuously operating on the fluid, while a motor operates intermittently in strokes. Most modern cars use ...

0

For the case of the nuclear generating plant, the difference between a motor and a turbine is a bit more subtle. In the nuclear generating plant, high pressure steam is generated by the heat of the nuclear reaction, and this high pressure steam is sent to a turbine. The turbine is connected via a shaft to a generator (which in some cases, can be a motor ...

0

I see where you're trying to get to. So let me just jump right in with the textbook nomenclature. You are interested in the distinction between a device doing work versus having work done on it. What you might not have realized is that a turbine and a motor are in two completely different families. Let me lay out the distinctions here: A pump does work, ...

2

A turbine is machine in which the kinetic energy of a moving fluid is converted to mechanical power by the impulse or reaction of the fluid with a series of buckets, paddles, or blades arrayed about the circumference of a wheel or cylinder. The mechanical power typically has the form of a torque on a rotating axis. A motor is generic term for a machine ...

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In practice, the equation is somewhat simpler than that given in your second link. The overall heat transfer coefficient, or U, is a combination of all of the individual heat transfer coefficients and thermal conduction through a tube wall. When these are combined, you end up with the equation $${Q} = {U}{A}\Delta{T}$$, where the $\Delta{T}$ term is the ...

6

We already do this - that's how food is grown in so many parts of the world where historically a desert or very arid biome has existed. There are a few problems with this approach. In the desert, there are two main ways you can get fresh water. You can pump it up from aquifers, or you can get it from the ocean and desalinate it. The main disadvantage of ...

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If you pump out ground water faster than it is replenished, it will be depleted, sooner or later (http://water.usgs.gov/edu/gwdepletion.html )

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Polymers such as wax definitely undergo phase transitions. You inquired about paraffin wax, which is oil-based. Paraffin wax is made of long rod-like molecules called linear straight-chain alkanes. It's solid at room temperature, but when refined as liquid paraffin and combined with water, it can act as liquid crystal, which complicates its phase diagram. ...

0

Ice has a sharp melting point temperature because it is a pure substance. Wax is a mixture of higher molecular weight hydrocarbons, so it doesn't have the same sharp melting point. While I have petrochemical experience in my background, I didn't work much with waxes, so I can't give you a firm estimate of the composition, but I suspect that web searches ...

1

This comes down to the fact that ice is a crystal, and wax (and chocolate) is a (glassy) polymer-like material. Here is the chart of stiffness of a polymer as it is heated. When it is cold, the polymer is in a glassy phase. As it is heated, it enters the "leathery phase", and it begins to soften. As it warms up more, the material becomes progressively ...

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