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Sensei

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Everything posted by Sensei

  1. Quote from http://en.wikipedia.org/wiki/Mass_in_special_relativity "The mass of composite systems" "The rest mass of a composite system is not the sum of the rest masses of the parts, unless all the parts are at rest. The total mass of a composite system includes the kinetic energy and field energy in the system." When we say f.e. proton has mass 938.272 MeV/c^2 we are talking about sum of relativistic masses of quarks, not rest masses of quarks.. It doesn't have to, if there is absolute frame of reference (which we cannot find). With extreme acceleration to relativistic velocities, new particles are created. p+ + p+ -> p+ + p+ + p+ + p- (proton colliding with proton is creating three protons and one antiproton) If relativistic mass is not real, then it has completely no sense. But it's real experimentally confirmed result.
  2. Literacy world map 2007: http://upload.wikimedia.org/wikipedia/commons/c/cf/Literacy_rate_world.svg Maybe he meant secondary illiteracy..
  3. If you can't read, you can't gain other people knowledge and learn from past discoveries (other way than mouth to mouth, it's easy to skew). If you can't write, you can't share your knowledge with other people and leaving sign "I was here". Maybe some peasants or cavemen thousands years ago had some knowledge, especially in agriculture and natural medicine (f.e. how to use vegetables and herbs), but this knowledge not written by anybody get lost in time.
  4. 150 years ago majority of people could not even read and write... One of the greatest improvements in Positivism in half of XIX century was building primary schools for everybody, even the poorest peasants in villages. Illiterate persons can't share their story with us, so we know how Egyptians, Romans, middle age people etc. lived only from stories written by rich nobility..
  5. You can't use vacuum. Imagine you have closed box half with air, half with water. If you will pump out whole air, it will cause water to have lower pressure and it will be still filling whole box, just with smaller density, lower pressure.. So why not fill it since beginning with pure water, without leaving any room for air? On youtube there is video in which scientists are pumping out whole air from closed room where is glass of water on table. After a couple seconds water in glass is starting boiling just because air is not pressing it anymore enough (it's changing state to gas). But if you are really bothering with arcs of electricity in air (why?), then use pure oxygen instead of air.. Electric arc will be making ozone in the worst scenario. Electric arcs are used by welders all the time.. Are you using silver for both electrodes? Lead probably would create some lead oxide http://en.wikipedia.org/wiki/Lead%28II%29_oxide Using AC instead of DC is making harder to find out what is going on, as 1/100 of second electrode is producing Hydrogen, 1/100 of second it's producing Oxygen. So they and result oxides are mixing together..
  6. You can see it on your own eyes by building diffusion cloud chamber and placing magnetic/electric field around it. If you're not familiar with them watch f.e. this video http://www.youtube.com/watch?v=Efgy1bV2aQo On youtube there is plenty tutorials how to build them though. I have build couple. It's $20 investment, if you have access to dry ice.
  7. You don't need any arguments to function to have not infinite recursion... int count = 100000; // global void f1( void ) { if( count > 0 ) { count--; f1(); } } When function is calling other function return address is stored on cpu stack. It has finite size. On Windows stack has default 1 MB size per thread. When stack is filled, application is crashing and is shut down automatically by operating system. So, there is really no problem in modern times. In the beginning of computers, it could be problem to detect whether program is halted or is simply crunching data, without task manager, GUI etc. which allows us now to check what is going on with our application.
  8. That can be childish easy to do, and working on any platform, any language- just add some code to regular startup module It's attached to every compiled executable at beginning, and after initializing things is calling main() function.
  9. Detector = polarization filter (in the simplest version of test). Also this article might interest you http://en.wikipedia.org/wiki/Quantum_eraser_experiment
  10. Collect bubbles of gas in test tube, similar way as we do it during electrolysis. Then when it will be full, fire it. If it'll explode, collected gas is hydrogen. If fire will be much stronger, then it's oxygen gas.
  11. If you want to produce just Hydrogen from water, you don't need to worry too much about material from which there are made electrodes. It's important only when you want to produce pure Oxygen or both. f.e. when you will use aluminum plates or wires, on negative electrode there will be created 8 times more volume of Hydrogen than Oxygen on positive electrode f.e. 25 cm^3 H (single test tube) and 3.125 cm^3 O. After a while you will see that aluminum is disintegrating and water is full of white suspenion. It's Al2O3. While using different materials for electrodes you will create different oxides. See post #9 and #11 in http://www.scienceforums.net/topic/79096-what-are-units-in-chemistry/ I have provided there more informations.
  12. Object in cosmic space once accelerated to 11 mps will continue going with that speed as long as particles from cosmic rays won't slow it down (or it won't be attracted by some massive object). Collisions with them or with photons from Sun or other stars will have effect in long term. But in short term, it's like discussing about changing path of 800 kg asteroid by cosmic rays and photons (negligible). 11 mps is half of speed of Earth around Sun (30 km/s).. Maybe you're thinking about accelerating 11 km/s^2 for 20 years instead? 20 light years is distance = 20 * 365.25 * 24 * 3600 * c = ~1.89*10^14 km not time.
  13. Temperature of particle is connected to its velocity. Hot particle is fast moving, cold particle is slow moving. Once hot=fast moving particle is colliding with slow=cold moving particle, it's giving part or all of its kinetic energy. It's never returning it back to source. Device such as engine has chamber to which there is injected fuel which is mixed with air (or pure oxygen), and burn together forming some kind of fast moving oxides. They're colliding with chamber giving it part of its kinetic energy, and heating chamber (unwanted effect). And moving f.e. piston (wanted by us effect). Such explosions happen dozen times per second. Engines are usually made of heavy durable metal to be able to stand these explosions. Metals are good at absorbing heat, temperature is nicely spread across whole engine. Air molecules after colliding with running hot engine from outside, are accelerated, and engine is cooled down, and it's lost forever energy. Remaining energy is emitted as photons at various frequency ranges depending on temperature. If temperature of metal is too high, it's starting emitting visible light (it's used in light bulbs), and in the worst scenario is changing to fluid. Engines could be surrounded by Peltier cells to produce additional electricity.
  14. Who said he had water in the first place in the cup? He could have some substance that after a while (or after heating) is crystallizing.. Street magicians are using one of them all the time, to show they are changing "water" (some undefined liquid) to "ice"..
  15. We can distill water to get pure H2O without minerals and other unwanted substances. But after pumping to the ground even pure H2O there is chance (close to 100%) that it'll be contaminated inside of Earth. During travel back to sea level molecules that was flushed by water/vapor will start gathering on installation.
  16. http://en.wikipedia.org/wiki/Geothermal_gradient Temperature increases ~25 C for each 1 km of depth average on Earth. Which gives 4 km average to reach 100 C. We need 100 C to heat water to become vapor. But it's not constant! Different locations will have different depths at which we will find enough temperature. Drilling 2-3 km well cost ~2 million dollars (at least for gas and oil), hydraulic fracturing is 0.5-1 mln usd. If you are thinking about it seriously you should start from making cheap drilling..
  17. NaCl dissolved in H2O is in reality ions Na+ and Cl-. They are spread evenly across of whole water, so we can say that distances between ions are pretty much equal (none part of water has higher concentration). From quantum physics point of view Sodium is giving away its electron (because it wants to have 2,8 electrons in shells, instead of 2,8,1), and Chlorine is taking electron (because it wants to have 2,8,8 electrons, instead of 2,8,7).
  18. Theory must be consistent with experimental data, not reverse. If you will send blue light and red light from lasers, they will reach detector at the same moment. So regardless of photon energy, frequency and wavelength, they must have the same velocity. Other example - if you have 3 km long fiber wire, and you will send data at frequency f0 and f1, you will receive data at the same moment 10 microseconds later. If their velocity would be different data would be desynchronized.
  19. Galileo had no idea about vacuum. He lived in 1564-1642. The first gas was discovered in 1766 (Hydrogen), 1772 (Nitrogen), 1773 (Oxygen), 1774 (Chlorine). The main question: I guess so repeatable every time..
  20. Mine code is for loop 5 times, not 3. And text displayed to user is different. fSum instead of aSum as name.
  21. To create just Hydrogen and Oxygen you need to use right material for electrodes. http://en.wikipedia.org/wiki/Electrolysis_of_water On picture on the right there are used pencils. That's no joke. Graphite is very good for this kind of job. But it's hard to find really pure one in the shops (at least here).. I went to the shop with multimeter and checked the all they gave me to make sure they're passing current (~75% did not work). If you will use metal such as f.e. Aluminum on one electrode there will be created Hydrogen with normal volume, but on second one much less than expected volume of Oxygen (1/8 volume of that of Hydrogen) - the rest of Oxygen will join with Aluminum and produce Al2O3 (I have couple liters of it at home exactly from electrolysis..) part/all of Aluminum electrode will literally disappear. One hour of electrolysis with 230 VDC (using silicon bridge rectifier KBPC-610 6A/1000V that cost 0.5$) is enough for wiping out entire electrode made of 0.5mm Aluminum plate. With such setup you can create 25 ml (single test tube) of Hydrogen in 91 seconds, and nearly 1 Liter in 1 hour. Different metals will produce different substances. You will see it immediately as f.e. some colorful substances in water making it opaque for a while. After leaving them alone f.e. for night or longer they will sink to bottom of container. For instance steel electrodes are producing red-yellow water, and absolute no Oxygen in test tube, so entire Oxygen is reacting with Iron.. And again - this can be used to measure masses of either Oxygen and metals. Measure mass of metal electrode prior electrolysis and after electrolysis (when part of it literally disappeared - it's now dissolved in water). After getting rid of water from container, there will remain just metal oxide, and you can measure its mass..
  22. Two waves.... ? I have 2 usd cheap laser at hand that has 5 mW max output, and wavelength 650 nm. 1 W = 1 J/s so 5 mW = 5 mJ/s = 0.005 J/s Photon with wavelength 650 nm has: E=h*c/650 nm = 6.62607*10^-34 * 299792458 / 650 *10^-9 = ~3.056*10^-19 J energy... Assuming (unreal) that there is no lost and all energy is converted to photons with such wavelength, this mine tiny laser will produce 0.005 J / 3.056*10^-19 J = 16,360,879,214,888,979 photons emitted per 1 second of work.. That's 16,360,879 per nano second. When such tremendous quantity of photons will collide with atoms in wall we see dot. From the all directions we look at it. Photons are reflected in the all directions
  23. Ep = m*a*h Distances traveled by object with acceleration a is: h=1/2*a*t^2 so m * a * 1/2*a*t^2 = 1/2*m*a^2*t^2 kg * m^2/s^4 * s^2 = kg * m^2/s^2 = kg * (m/s)^2 And we are receiving other equation back. Ek= 1/2 *m * v^2
  24. Then your teacher is incompetent.. Because it's in flagrant conflict with this "(Hint: use pass by reference)"... In ANSI C, you have to replace references by pointers. #include <stdio.h> void getNumSum( float *aSum ) { float data = 0.0; printf("Please input a float number: "); scanf("%f", &data ); *aSum += data; } void main() { float aSum = 0.0; for( int i = 0; i < 5; i++ ) { getNumSum( &aSum ); printf( "Sum %f\n", aSum ); } }
  25. References are in cpp, not in old c. Rename file and should be fine.
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