OrbitalPete
OrbitalPete t1_j7ejhlz wrote
Reply to Why oil fries, while water boils? by SaboKunn
When you put food in oil it's at s much hight temperature than boiling in water. As a result moisture in the food is boiled out which dies the food. Its also hot enough that browning (maillard reactions) and crisping can occur.
The bubbling when you deep fry is the water coming out of the food and vaporising. You can get pills to boil as well, although they aren't pure liquids boiling is generally accompanied by a lot of smoking, burning of components in the oil, and - because oils are generally flammable - the vaporised fraction often ignites.
OrbitalPete t1_j6m8ett wrote
Reply to comment by torama in can gemstones be melted into a gradient? by Acceptable_Shift_247
You only start crystallising quartz in a silicate melt (I.e. magma) below about 800 degrees. Above that the silica only gets accommodated in other minerals.
OrbitalPete t1_j6m0dr1 wrote
Reply to comment by torama in can gemstones be melted into a gradient? by Acceptable_Shift_247
OK, so forgive my lack of mineralogy but why does quartz only start dumping out of silicate melt below about 800 degrees? Is this at STP?
OrbitalPete t1_j4zaxl3 wrote
Reply to Is there any model or method to calculate how groundwater distributes spatially? by EggLemon3000
Hydrogeology and hydrology are the fields you're looking at here. It's not as straightforward as you might imagine.
So yes there are models, but they are of varying precision in different settings, and dependent on the quality of your subsurface knowledge.
OrbitalPete t1_j2cueis wrote
Reply to ELI5: How web crawlers and other engines don’t constantly get infected with viruses? by Officialsparxx
Think of it like the difference between photocopying a book and reading one. Your Web browser reads the page code and interprets it. Crawlers and things like the way back machine just copy the page code or specific bits in the code.
OrbitalPete t1_iyw9f9q wrote
Reply to comment by MostCuriousExplorer in Would the speed of sound in a metal increase if I heated it up? by Altazaar
I only really deal with it in rocks. The same physics applies to all metals (and other materials!). There's a huge amount of metallurgy research though - look for stuff on young's modulus, bulk modulus and shear modulus. P wave velocities (sound wave, acoustic wave, compression wave - all mean the same thing) aren't used as much in metal analysis, but they are used. You can use the moduli and density data to work out how P wave will respond though.
OrbitalPete t1_iyw606j wrote
Reply to comment by MostCuriousExplorer in Would the speed of sound in a metal increase if I heated it up? by Altazaar
Sound can travel through any medium except vacuum. Temperature is only enforcing a control because it changes other physical and mechanical properties of a material. Its better to think about those different parameters individually, because the temperature effects are non linear, and vary by material.
Remember- freezing point is simply the point at which a liquid becomes solid (typically we talk about this for water, which occurs at 0 centigrade at standard pressure). We can still transfer pressure waves, the state of matter will change the speed though.
OrbitalPete t1_iyw2ogc wrote
Reply to comment by MostCuriousExplorer in Would the speed of sound in a metal increase if I heated it up? by Altazaar
It's not straightforward, but in general yes
OrbitalPete t1_iyvuj3a wrote
As you heat metal it becomes much weaker to resisting volumetric change and shear stresses (the bulk modulus (K) and shear modulus (mu) both reduce). Density (rho) reduces very slightly. You will be reducing the speed of sound (P wave velocity, Vp) substantially.
Vp = SqRt((K×4/3mu)/rho)
OrbitalPete t1_iuc8ivy wrote
As tectonic processes move the crust around, smooshing it together, bending it, stretching it etc, it also has lots of fluid moving through it. Some are hot, some are cold, some are water based, some are magmatic. They can have wildly different chemistry. As they interact with different rocks at different pressure and temperatures those fluid can dissolve some things. And like putting milk in chocolate cereal - some stuff dissolves into the fluid and others don't.
So while a rock might only contain, say, 0.003% gold, hot fluids with the right temperature, pH and other conditions might be able to dissolve the gold and not much else. That will remove the gold from the rock and put it in the fluid.
As the fluid moves through cracks and other fluid pathways it can cool down or change its solvent properties, and particular minerals will get dumped out of it in highly concentrated volumes.
OrbitalPete t1_je8xuhg wrote
Reply to Eli5:How does conversion from celsius to Fahrenheit work and is there a "linear correlation" by Moewillgo
There is a linear correlation, but the origin is not at 0.
https://qph.cf2.quoracdn.net/main-qimg-7df15e6faf5f599060c6884fc88d39d7-pjlq
Both scales have a constant linearity to them, and 1 degree Celsius increase is always a 1.8 degree Farenheit increase.
This graph plots one against the other, as you can see showing a linear correlation. https://d1uvxqwmcz8fl1.cloudfront.net/tes/resources/11829524/ff0efc69-c7a4-4963-ba86-c733ac6602a3/image?width=500&height=500&version=1541452521288