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Everything posted by Sensei

  1. 12.32 grams of metal is sum of masses of zinc that didn't react plus silver that was made from silver nitrate.
  2. Practice is better than theory I have produced plenty of Al2O3 . 3H2O At the beginning of production they can look like long ultra thin fibers floating in water. You can see couple photos here: It needs to be heated (or leaved until water vaporize) to have pure Al2O3 One is floating on water (for year or so), because bubbles have hydrogen and oxygen gases.
  3. Rasen58, do you feel confused by mine post? I am really sorry for that..
  4. At least author will learn how to calculate number of particles and mass of single particle or molecule. Aluminum has 13 protons in nucleus and 13 electrons. http://en.wikipedia.org/wiki/Aluminium Boron has 5 protons in nucleus and 5 electrons. http://en.wikipedia.org/wiki/Boron It's obvious that when number of protons is equal to number of electrons they cancel their charges and we have neutral element.
  5. 1 mol (6.022141*10^23 particles or molecules) of Chlorine has ~35.5 grams (stable isotopes with 35u ~75% and 37u ~25% abundance). So 3.9 g / 35.5 g = 0.11 * 6.022141e+23 = ~6.6*10^22 particles. 6.6*10^22 particles / 3 Chlorine in each molecule of MCl3 = ~2.2*10^22 molecules of MCl3 1 g / 2.2*10^22 = ~4.545*10^-23 g per particle of M Divide it by 1 u = ~1.66*10^-24 g 4.534*10^-23 g / 1.66*10^-24 g = ~27u Aluminum has ~27u mass. Aluminum has charge +13 in nucleus (and 2+8+3 electrons = -13 charge) Boron has +5 in nucleus (and 2+3 electrons = -5 charge) http://en.wikipedia.org/wiki/Boron Either of them has 3 valence electrons.
  6. If you will be doing science for real in future, I suggest to getting Full HD camera with tripod. The more frames per second, the better. It's device that will keep camera in the same position and angle for a long time. Then copy movie from camera to computer, and load it to movie editing software such as VirtualDub (it's free). You can then precisely find time of some physical event counting frames between start and end of event. It's much more precise than using stopper. Times you can enter to OpenOffice SpreadSheet application (it's free). And generate chart. After that you will see what I said in #3 post. That cycles of spinning back and forth clockwise/counter-clockwise are shorter and shorter, the longer experiment is running. According to Internet some of them costs $1-$1.5 for piece. They are also used by fishing people, so you should find them in fishing shop. http://en.wikipedia.org/wiki/Fishing_swivel http://www.fishingwarehouseshop.co.uk/product_info.php/products_id/5661 It's for 2.61 ukp = $4.4 (10 pieces in package) so single one $0.44
  7. Fishing line is usually made of plastic. If you don't know something, enter it in google, and you will have answer. http://en.wikipedia.org/wiki/Fishing_line In USA people (small amount. Personally I don't know anybody fishing) are fishing mostly for fun, not for food (except Alaska). It's such entertainment. Most of them are later releasing fish.
  8. I guess so this question is not full? What devices or things we can use during testing.. ? If I will rub magnet on needle, needle will become magnet (one rub in one direction is enough for mine needles). Then you can carefully place needle on water in glass, and it'll be pointing north-south direction, or point to the nearest strongest magnet. If I will rub iron on needle, nothing will happen. Needle won't change to magnet. Another test with f.e. aluminum pipe with enough hole placed vertically. Iron will pass through pipe at pretty normal speed and time. Magnet will be passing through pipe significantly longer (20 times longer in mine test). I have 2 meters long aluminum pipe with diameter 12 mm and 10mm diameter of hole, 1mm thickness of metal. Strong neodymium magnet (8mm diameter, 3mm height) will pass through it in 12-13 seconds. That's 20 times longer than other items than magnet. When I stacked 3 such magnets, time increased to 19 seconds. Items made of aluminum or iron with similar size to magnet are passing through it in 0.63 seconds approximately (too fast to count precisely using stopper, so used d=1/2*a*t^2 equation t=sqrt(2*2/9.81)=0.63 s)
  9. Repeating multiple times the same experiment is essential. Just yesterday I received shocking results that were quite senseless. And after repeating experiment, I found where error in measuring apparatus happened. Does water always was from the same source? Is it water from waterpipe? They can have additional small amount of Chlorine in gas form Cl2 + H2O -> HClO + HCl or others NaOCl, Ca(OCl)2, CaClOCl, or Chloramine. If water was not perfectly clear, after heating it, there could be additional reactions between Chlorine and other molecules present in dirty water, or container. Water was heated in plastic, metal or glass cup? I suppose so aunt was waiting until water has at least room temperature before giving it to plant? That's quite essential question. Temperature of water that we can stand putting hand inside, plant might not tolerate.
  10. In western countries, you pretty much have to double that age to be considered mature. After studies. After getting job. After starting living on your own, in rented or your own apartment. Maturity is state of mind. Not strictly correlated to age. Don't you think so that you should first truly learn about science, to answer somebody else questions.. ? What value has answer from somebody who barely know stuff in area he is trying to answer?
  11. Not quite. Any alpha decaying isotope is source of Helium-4. Alpha particle is Helium-4 nucleus. http://en.wikipedia.org/wiki/Alpha_particle
  12. It's kinda like saying that you will know positions, momentum, energies and charges of the all particles in entire universe.. Influence of charged particle that's at short distance can be to some level of precision measured. If electrons are f.e. at one capacitor plate, and absence of them on another plate, we can calculate what is charge on them and what is voltage between them. But if we take electron that's f.e. billion light years from here, it's influence is billion (or billion^2) times less powerful (any inverse-square law equation doesn't have limits for 'r' parameter, either in Newton's equation, nor in Coulomb's law). Physicists ignore it as regular practice. It's influence is negligible, ultra small, but higher than 0.
  13. Indeed. But human made devices never fly with v>30,000 m/s (or so). That's 0.1% of c. Voyager-1 has v=17,000 m/s relative to Sun.
  14. Rajnish Kaushik, read about Gold Foil Experiment http://en.wikipedia.org/wiki/Geiger%E2%80%93Marsden_experiment
  15. 15+6 =21 21!=51090942171709440000 5! = 120 6! = 720 5!+6!=840 51090942171709440000/840=60822550204416000 No fraction, so it's natural number. ps. I see you wrote "5", instead of "15". Which was later reedited and fixed to "15".
  16. If you will try dividing any number by 0 on computer in f.e. C/C++ language, you will get NaN result (Not A Number). http://en.wikipedia.org/wiki/NaN Some computer languages might even throw exception (halting of application, crashing of application). (.NET Framework C#/Embedded C++ is example of such language if I recall correctly) Therefor depending on context we can use f.e. if( value == 0 ) { // treating 0 as very very small. Division input by very small gives very big result (except 0/0). if( input > 0 ) { result = INFINITY; } else if( input < 0 ) { result = -INFINITY; } else if( input == 0 ) { result = 0; } } else { result = input / value; } Any dividing by variable might cause result to be NaN and serious problems in other parts of algorithms later (in the worst scenario lost of data, and crashing of application), if you don't catch it! You have to think about it writing ANY computer program which is dividing.
  17. But you're doing slightly different algorithm than me in post #4. Any example value that is causing it? I scanned the all first 1,000,000 numbers using two different algorithms and found 78,498 primes. Exactly the number we should get.
  18. It's the simplest possible code for range between 2 and 4 billions primes. You could degrade range to 2...65536 by replacing "unsigned long long" by "int". And degrading speed by removing sqrt() line. But I see no sense in this action. bool IsPrime1( int value ) { if( value < 2 ) return( false ); for( int i = 2; i < value; i++ ) { if( ( value % i ) == 0 ) { return( false ); } } return( true ); }
  19. If we will be writing code for you, you won't learn anything.. The simplest prime search code (copy'n'pasted from mine own application): bool IsPrime1( unsigned long long value ) { if( value < 2 ) return( false ); unsigned long long max = (unsigned long long) sqrt( (double) value ); for( unsigned long long i = 2; i <= max; i++ ) { if( ( value % i ) == 0 ) { return( false ); } } return( true ); } It will work with primes smaller than 4,294,967,296
  20. You are in one place dividing by variable. If it'll be 0, you will end up with error as well. You have to check whether it's equal 0.0 to prevent that. If sqrt() from negative is really needed you can try using following function instead: double negative_sqrt( double value ) { if( value >= 0 ) return( sqrt( value ) ); return( -sqrt( -value ) ); } It will make sure that you're not taking square from negative, and preserving sign of value. f.e. negative_sqrt( -100 ) will return -10 But it's not general purpose equivalent. It depends on context in which you might need sqrt(). -10 * -10 = +100 after all.
  21. The more important is lack of GR at quantum level..
  22. Take sqrt() only from positive numbers.. So use fabs()/abs() or equivalent code, to get rid of negatives... BTW, y[] is defined as float, so complex class sqrt() is never executed, only regular one.
  23. sqrt() the most likely is returning NaN (Not A Number) for negative input. The same happens with regular hand calculators (E letter appears etc.) http://en.wikipedia.org/wiki/NaN It's mentioned on wiki page "There are three kinds of operations that can return NaN: [...] The square root of a negative number."
  24. value ^ power is not working in C/C++ the way as in math. It's bitwise xor operator.. http://en.wikipedia.org/wiki/Operators_in_C_and_C%2B%2B
  25. It's better described on Electronvolt wiki page, than I can express it.. http://en.wikipedia.org/wiki/Electronvolt eV is simply alternative unit of energy, instead of Joules. eV/c^2 is alternative unit of mass.
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