Tempest Posted March 7, 2014 Share Posted March 7, 2014 Ask science questions, talk about projects you're doing, post news you find, or just discuss. Yes, this a nerdy thread. Two questions: What is the equation to find the density of an incompressible liquid (i.e. water) based on the original density, temperature and pressure? Are all liquids incompressible or are there certain one that aren't? I ask because I'm doing some calculations about a nuclear reactor and cooling it with high pressure water. It'd be concentrated under at least 15Mpa of pressure and upwards of 100. I'll post more later. I should look at that text book. Quote Link to comment Share on other sites More sharing options...
Maelstrom Posted March 13, 2014 Share Posted March 13, 2014 Incompressable? It's been a while. Probably gotta use a PV=nrt equation to find it at whatever variable you're changing. Or two of em because it'Lol probably be easier to solve as a ratio. Quote Link to comment Share on other sites More sharing options...
Tempest Posted March 13, 2014 Author Share Posted March 13, 2014 I actually figured this out awhile ago. I still working on the design though. You do have the right equation for ideal gas though. Which Helium under pressure would be. Quote Link to comment Share on other sites More sharing options...
Bluewolf Posted March 13, 2014 Share Posted March 13, 2014 Oh cool SCIENCE! (I find it odd that I learn just as much as I do here as at school) Quote Link to comment Share on other sites More sharing options...
Maelstrom Posted March 14, 2014 Share Posted March 14, 2014 This thread needs more string theory. Quote Link to comment Share on other sites More sharing options...
Tempest Posted March 14, 2014 Author Share Posted March 14, 2014 Bleh. Don't get me started on string theory. Older news but I think it's still relevant. It's only the first part: When a cold snap hits and the temperature drops, theres nothing to stop it from falling below zero, whether Celsius or Fahrenheit. Either zero is just a mark on a thermometer. But drive a temperature lower and lower, beyond the coldest realms in the Arctic and past those in the most distant reaches of outer space, and eventually you hit an ultimate limit: absolute zero. Its a barrier enforced by the laws of physics below which temperatures supposedly cannot possibly go. At minus 459.67 degrees Fahrenheit (or minus 273.15 Celsius), all the heat is gone. Atomic and molecular motion ceases. Trying to create a temperature below absolute zero would be like looking for a location south of the South Pole. Of course, scientists perceive such barriers as challenges. And now some lab trickery has enabled researchers to manipulate atoms into an arrangement that appears to cross the forbidden border. With magnets and lasers, a team at Ludwig-Maximilians University Munich in Germany has coaxed a cloud of 100,000 potassium atoms into a state with a negative temperature on the absolute scale. It forces us to reconsider what we believe to know about temperature, says Ulrich Schneider, one of the leaders of the research team. As a bonus, the weird configuration of matter might provide clues to some deep mysteries about the universe. Schneider and his colleagues relied on laser beams to trap the atoms in a grid, kind of like the dimples in an egg carton. By tuning the lasers and applying magnetic fields, the team could control the energy of the atoms, key to manipulating temperature. Ordinarily, not all the atoms in a sample possess the same amount of energy; some are slow-moving, low-energy sluggards, while others zip about like speed demons. A higher proportion of zippy atoms corresponds to a higher temperature. But most of the atoms are always slower than the very fastestwhen the temperature is positive. With their magnet-and-laser legerdemain, the German scientists pushed the majority of the potassium atoms to higher energies, the opposite of the usual situation. Though that may not seem like a big deal, the switch messed with the mathematics that determines the gass temperature, leading to a negative value. Technically, physicists define temperature as a relationship between changes in entropy (a measure of disorder) and energy. Usually more energy increases a systems entropy. But in the inverted case, entropy decreases as energy increases, flipping the sign of the relationship from positive to negative. The atoms had a temperature of minus a few billionths of a kelvin, the standard unit on the absolute scale. The catch is that scientists reached temperatures below absolute zero in a mathematical sense only. While the negative temperatures were numerically lower than absolute zero, they werent colder. In fact, the gas was superhot, hotter than anything with a positive temperature could ever be. Besides achieving a weird temperature state, the new work replicates a peculiar feature of the universe. Negative temperature systems also possess negative pressure, which on cosmic scales is causing the universe to expand faster and faster. Physicists call the universes negative pressure field dark energy, but they havent been able to figure out exactly what it is. Perhaps negative pressure in a lab could offer insights. www.smithsonianmag.com/science-nature/scientists-are-trying-to-create-a-temperature-below-absolute-zero-4837559/ Quote Link to comment Share on other sites More sharing options...
Deleted User Posted March 16, 2014 Share Posted March 16, 2014 That's like trying to go faster than the speed of light. In fact the closer you get to the speed of light and absolute zero respectively, the more impractical and more fruitless the spending becomes. Do we really need to spend an additional Billion dollars to get from 99% to 99.9%?? As far as my current interest, from what I hear, Nuclear Fusion is inching it's way closer and closer to being possible for humanity to potentially use someday as a alternative source of energy. Quote Link to comment Share on other sites More sharing options...
Tempest Posted March 16, 2014 Author Share Posted March 16, 2014 Actually it has been achieved and it creates negative pressures. It's extremely strange form of matter. But the difference in energies bewteen 99 and 99.9% is more than you know. Since: E=mc2+mv/(sqrt(1-v2/c2))*c Which increases mass as velocity apporaches the speed of light. So in a particle accelerator is does make a difference. Quote Link to comment Share on other sites More sharing options...
Deleted User Posted March 16, 2014 Share Posted March 16, 2014 Well if there's something below absolute zero, than the whole Kelvin scale has become useless. Quote Link to comment Share on other sites More sharing options...
Tempest Posted March 16, 2014 Author Share Posted March 16, 2014 Not really. Below absolute zero is actually infinitely hot basically. It wraps around. Quote Link to comment Share on other sites More sharing options...
Deleted User Posted March 16, 2014 Share Posted March 16, 2014 wat? Quote Link to comment Share on other sites More sharing options...
Ojama Yellow Posted March 16, 2014 Share Posted March 16, 2014 My brain can't handle this. Quote Link to comment Share on other sites More sharing options...
Tempest Posted March 16, 2014 Author Share Posted March 16, 2014 I could say things that are worse. Don't get me talking about black holes. Quote Link to comment Share on other sites More sharing options...
Ojama Yellow Posted March 16, 2014 Share Posted March 16, 2014 Please don't. Sweet Jesus have mercy. Quote Link to comment Share on other sites More sharing options...
Deleted User Posted March 16, 2014 Share Posted March 16, 2014 Give me a once over on the cliff notes. It amazes me that you're this informed on these kind of matters at your age. Quote Link to comment Share on other sites More sharing options...
Tempest Posted March 16, 2014 Author Share Posted March 16, 2014 An endless curiosity, a nearly idetic memory, and and an iPad during class means I can learn alot. Quote Link to comment Share on other sites More sharing options...
Deleted User Posted March 16, 2014 Share Posted March 16, 2014 iPad??? Quote Link to comment Share on other sites More sharing options...
Magus Posted March 16, 2014 Share Posted March 16, 2014 I like black holes, they tend to ignore the laws of time and space. Quote Link to comment Share on other sites More sharing options...
Deleted User Posted March 16, 2014 Share Posted March 16, 2014 I disagree with the way you've worded that. Black holes tend to ignore the laws of time and space as we understand them. I'm sure they follow all the proper procedures on the universe, or possibly multiverse. Quote Link to comment Share on other sites More sharing options...
Tempest Posted March 16, 2014 Author Share Posted March 16, 2014 The only thing of black holes that violates our known laws is the information paradox. Realativity and Lorentz transformations correctly predict black holes' event horizons and time dilations. The information paradox is that the singularity supposedly destroys energy and matter. Energy can be converted between matter and vice versa, but it cannot be outright destroyed. On top of that, math itself breaks at a singularity, because there is a measurable mass but zero volume. Hence, dividing by 0 to calculate density, which is generally defined as undefined. Quote Link to comment Share on other sites More sharing options...
Magus Posted March 16, 2014 Share Posted March 16, 2014 I did badly word that, what I was going for was at the actually event horizon, that is where all the laws physics stop making sense, time and space become distorted, and the math (as tempest stated) is completely bananas. They are crazy things that shouldn't exist, yet they do and are interesting to discuss. Quote Link to comment Share on other sites More sharing options...
Tempest Posted March 17, 2014 Author Share Posted March 17, 2014 It's the end of the video that's really interesting. This is actually where I get most of my science news: Quote Link to comment Share on other sites More sharing options...
Deleted User Posted March 20, 2014 Share Posted March 20, 2014 Boeing's X-51 is pretty impressive clocking in at nearly 4000 MPH, however completely impractical with a range about 400 miles, Only staying in the air roughly 5 minutes. Oh and it doesn't exactly y'know land, well not in the traditional sense of landing a plane. Quote Link to comment Share on other sites More sharing options...
Tempest Posted March 20, 2014 Author Share Posted March 20, 2014 When we develop Scramjets to full maturity I'll will be enthralled. The entire project had been really interesting but I didn't even know that it could go 400 miles. Quote Link to comment Share on other sites More sharing options...
Aizen805 Posted March 20, 2014 Share Posted March 20, 2014 I'll be honest here, I have no idea what is happening, but astronomy does interest me greatly. I look at the occasional article that pertains to astrophysics, but aside from that the rest of this just seems funny (Mainly because it confuses the shit out of me.) Quote Link to comment Share on other sites More sharing options...
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