Jump to content

John Cuthber

Resident Experts
  • Posts

  • Joined

  • Last visited

  • Days Won


Everything posted by John Cuthber

  1. Well, I guess you could go with finely powdered tungsten in starch/water. Why do you want to know?
  2. Thanks for the link but you are the third person to point out the problem with that theory.
  3. Er, is it clear that chickens experience emotions? Chickens are pretty near brainless anyway. The problem is that if we created an animal, say a chicken, that was completely brainless it wouldn't know how to feed itself. As soon as we give it enough brains to peck grain, someone will say "It is doing that because it feels hunger- it must be consious". The problem, from my point of view, is that many people anthropomorphise animal behaviour and presume that (here's a nice emotive example) because an injured dog barks and whines, it must feel pain. A long time ago when I was at school someone made a computerised robot that trundled round the floor- it had sensors that detected when it hit something and it backed off and turned. I also had a computer and it had a speech synthesis chip connected to it. We connected the 2 computers together- now, when it hit something it said "Ouch!" and backed away. It said ouch but did it really feel pain? Dogs spend enough time humping their owners' legs to prove that they certainly don't know they are dogs, I question whether they have a sense of self. If a dog doesn't have an understanding that it is an individual then how can it think "I am in pain"- there isn't an "I" to think that. OK, I realise that not everyone will agree about dogs not being self aware. There's room for experiment and debate on that question. Chimps certainly do have a sense of self; I can't see anyone saying there's room in a cockroach brain for that sort of abstract thinking. I have no problem with eating animals that don't know they are alive and cannot understand death. As a matter of principle I think farm animals should be well cared for- not because they are sentient, but because we are, We have a choice in the matter and it demeans us not to look after our prospective dinners.
  4. With the belt moving backwards fast enough there would be more frictional force pulling the plane back (by its wheels) than thrust from the engines. It wouldn't move forwards so it wouldn't generate any lift. However, as I said earlier, with the belt runing that fast it would drag enough air past the wings to generate lift anyway.
  5. "And there have been fusion reactors for decades." There is at least some evidence that one particular fusion reactor has been running for at least something like 4.5 billion years. It's about 93 million miles away. BTW, the site linked in the original post now gives a reasonable idea of fusion.
  6. Dividing a line segment into any number of parts is simple enough. Trisecting an angle isn't.
  7. If this experiment had worked and produced fusion as they said it did then the neutron flux released by the reaction would have killed them. They are still alive therefore they didn't do cold fusion. Is there anything more to say on this once we have established that it simply never worked?
  8. Interesting idea. I think thatif you maded SiCl bonds they would hydrolyse as soon as you took the stuff into suspension in water. It would be interesting to reduce a gold salt in the presence of some nanoparticulate silica and see if the Au "plated" out onto the surface. I think that converting the "SiOH" to "SiSH" might help. Not sure about that but peopele seem to use thiols for putting monolayers onto gold electrodes (and I'm not sure how you would do it anyway).
  9. Well, the man made ones are horribly expensive and they are radioactive (but so are some natural elements).
  10. "Actually Honey contains no sugar (may be a little, i am not sure)" That's a matter of definition. Honey contains about 1% sucrose (ordinary cane or beet sugar) but, if you accept that glucose and fructose are sugars (and I think most people would), then it's about 75% "sugar". I don't think grain crops atract bees, but the other flowering crops are often sprayed and the chemicals get into the honey. Since the quantities of these residues are low in the fruits etc that are being grown it's not unreasonable to hope that the levels of residual pesticides in the honey are also low.
  11. It's probably worth adding that the carbon rods are still there in perfect working order after the battery is flat so if you know someone who uses these batteries the carbons are free. BTW, my point was not that pure water is particularly useful as a conductor but that what was put forward as a "fact" simply wasn't true. I doubt that he was using ultrapure water and ensuring that the air didn't add CO2 to it so I don't think talking about 50MV is relevant. It also fails to account for the area of the electrodes as well as their separation. Even then there would still be the fact the the insulation of the water would break down at that sort of voltage (or anything close to it).
  12. That's not absorbtion or emision. That's internal transfer and happens later.
  13. There are many different definitions of spam. At least in this case it is well written and properly targeted- we are a group who might want to hear about the GM debate. Also, to be strictly fair, just because he's paid by monsanto doesn't mean that it's advertising- very few of us are going to go out and by GM tomato seeds as a result of his posting. To me it seems patronising to ignore the opinions of the farmers concerned just because we heard of them from a (possibly) biassed source.
  14. The simple answer is that you could probably get away with it. Most people commit crimes for a reason and that fact makes things much easier for the police. They just start by working out who wanted the victim dead. If you killed an unknown stranger for no real reason then, unless they were lucky (and, BTW, has anyone noticed that on CSI they are always lucky and the perpetrator always leaves a single hair behind? He's never shedding like a mangy cat) the police wouldn't know where to start. This idea was used as the basis for a murder story "strangers on a train" http://en.wikipedia.org/wiki/Strangers_on_a_Train where 2 people agree to commit murder for the other one. neither has a motive for the killing he undertakes. It turns out not to be that simple. On the other hand, in my experience, it's much easier to get away with murder if it looks like an accident or a suicide. If the police don't think there's a murder they don't look too hard at who might have committed it. (And I was joking about "in my experience")
  15. I did that experiment when I was at school. We used rock wool, the stuff used for insulating roofs and such. Alumina would probably work too. This page might help you http://en.wikipedia.org/wiki/Mineral_wool
  16. Initially, NaOH at the cathode and chlorine at the anode. the NaOH diffuses across and then reacts with the Cl2 to give NaClO. This can also get oxidised to NaClO3 etc. Of course, all this presumes that your electrodes are inert. Overall you get quite a mixture, but no sodium. You can make sodium by electrolysisng molten NaOH but I don't recommend doing that at home and the yield isn't very impressive because the stuff tends to catch fire as soon as you make it.
  17. I'd rather not go to KFC if you don't mind.
  18. In the case of Mg(ClO4)2 it might lead to the destruction of the H2Se, the equipment and significant bits of the lab and experimenter. Silica gel or CaSO4 might work, but there would probably be some absorbtion which would be more than a little troublesome when you came to reuse the drying agent.
  19. I can't help thinking that, if his question had been adequately answered, he wouldn't have sought clarification. On the other hand, with the way the question is posed, I think it's from homework or an exam so I guess he will get an answer. The simple answer (rather than invoking 2 photon processes and metastable states) is that an IR photon doesn't have much energy and so cannot excite the molecule up to a highly excited state from which visible light could be emitted. BYW, if " absorbtion and re-emission comsumes a little bit of energy," where does it go?
  20. NaO doesn't exist- it would need the Na to be in a 2+ oxidation state. (Na2O2 does exist, but that's another matter) Na2O exists, but it reacts with water to form 2 molecules of NaOH. NaOH reacts with H2SO4. To be honest, I'm not sure what the sulphur containing product(s) of oxidising thiosulphate with peroxide are. Did you do this reaction directly? It's just that people usually use iodide/ iodine for this sort of reaction.
  21. "ordinary water doesn`t conduct electricity doesn`t conduct electricity very well, in fact pure water doesn`t conduct at all." Oh yes it does. The H+ and OH- generated by self ionisation mean that it has a lagre but finite resistivity. This depends on temerpature but near room temp it's about 20MOhm cm The rate of production of H2 and O2 depends solely on the current. Once you have a high enough voltage to decompose the water, raising the voltage just reduces efficiency and generates waste heat. On the other hand, to get more current you need to raise the voltage or get bigger electrodes, put them closer together and make sure the material between them is a good conductor (like dilute acid rather than water).
  22. In a compound the constituents are generally present in fixed ratios, for example in salt NaCl there are exactly as many Na as ther are Cl. For a mixture like white gold the components can be present in (more or less) any proportions. Also, in compounds (even those where the ratios are not constant- the so called nonstoichiometric materials) the components generally have defined places in the lattice or molecule.
  23. Chemsiddiqui, Asbestos is banned in quite a lot of the world so I doubt that you need it. the rockwool stuff used as insulation may well do the job. When you wrote "hi, we were at the laboratory last week trying to do some of the chemistry experiments in the college? but we could not do it beacuse we did not know what exactly was mineral fibre and ceramic fibre. " what were you hoping to do? We might be able to help better if we understood better.
  24. I rather doubt the pins were ever pure gold. It's so soft the pins would buckle rather than plug in. (Though I agree it would have been better if Tater had read the thread).
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.