All Activity

This stream auto-updates     

  1. Past hour
  2. Which is more accurate when calculuating current/voltage/resistance?

    You say things like this which is simply wrong, because an off the peg cheap multimeter will generally give better precision ( nominally a part in 2000) than most analytical chemistry (Typically a few parts in 100). and which is true, but irrelevant because it muddles sensitivity with precision. So, it's not a matter of my understanding what you say. I wonder why you say things that are wrong or irrelevant. I certainly don't feel I'm doing any harm by pointing out what you are doing. My point is that you can't (usually) model, calculate or simulate what will happen as accurately as you can measure it. So the answer to the OP's question (the one they posted, rather than the one you imagined) is that measurement is more accurate. I think this sums it up pretty well
  3. Which is more accurate when calculuating current/voltage/resistance?

    Yes. The difference is that I understand what you are saying, but you don't seem to (want to?) understand what I am saying.
  4. What is your MBTI?

    Myers-Briggs Type Indicator. I did one test online and I got INFP. What is yours?
  5. What is your MBTI?

    Myers-Briggs Type Indicator. I did one test online and I got INFP. What is yours?
  6. Which is more accurate when calculuating current/voltage/resistance?

    Get what? I still get that being able to measure something at 1% is not the same as measuring it to 1%. Well, actually, they will. If, I breathe on it I will add water, but not chromium. That will reduce the chromium content. The change will be tiny- a few milligrams of moisture on a few tens of grams of metal will change the % chromium by a few parts in ten thousand. That's a much smaller change than I can measure the % chromium to in the first place. But I can measure the water content of the steel to that precision- I just weigh it, dry it, and weigh it again. Better yet, I can heat it in a stream of dry air and pass that air over a sorbent which traps the moisture (given up by the metal). And, since the mass of the trap can be small, I can measure the change in moisture quite easily- even if the original metal block is a kilo. I can measure moisture on a kilo of metal to a few parts per billion. But I still can't measure it to much better than 3 digits. Do you understand that difference?
  7. capillary pump

    Trees can do it. Up to a maximum height of 115 metres. The way that they manage it, I believe, is by evaporating the water in the leaves, reducing the pressure in the tubes, so the liquid is forced up by root pressure. Obviously, the water evaporates at the top so it wouldn't be usable. I don't know how the roots create enough pressure to push water to the top of a Coastal Redwood, or Australian Mountain Ash at over 100m tall. Maybe energy manufactured in the leaves is used to create the root pressure, so it might not be possible to copy the process.
  8. Today
  9. Most components have known manufacturer resistance values which can be used to calculate but there is always an associated tolerance. Sometimes much at 20%. Then there are variables like temperature and electrical insulation integrity which would need to be measured and corrected for prior to making the calculations. The only reason I have ever done such calculations is for troubleshooting purposes to see if a malfunctioning circuit had appreciably more or less resistance than it should. Even then I would only do that for circuit where individual components could not be removed or closed (isolated) for measurement and also where measuring Amperage wasn't an option. In my experience calculations are a must for designing circuits, obviously, but for maintenance or troubleshooting I would nearly always prefer to put a meter on it.
  10. Which is more accurate when calculuating current/voltage/resistance?

    You still don't get it do you? Consider some real world electronic circuit (ie one that performs some function). Now measure the voltage at one of the points in the circuit with your fancy voltmeter - you can only measure one at a time with one meter. Now look at the circuit. Breathe on it Stand it in the sunlight Put in in the fridge. Allow the battery terminals to corrode and/or use a half exhausted battery. Each of these and many more will affect your reading. None of these things will affect your piece of chrome steel or your measurement of chromium content. The point is that you want the same situation for the actual operation of whatever the job the circuit does, even though the voltages are different.
  11. Literary advisor?

    Thanks for the feedback Quiet! That is OK with me. Just remember to PM me when the novel is released, I'll try to get hold of a copy
  12. Did Christianity start with a real human Jesus?

    Why do you think they were peasants and fishers? So then there was scripture about Jesus, yet the Gospels were written at least 4 decades later This also goes in against your idea that they were illiterate. Those letters don't mean anything. The Gospels are probably based on the first Gospel, it's very normal they have a likewise plot. Which source? Did Paul mention Nazareth? How do you know this :" Ehrman was not criticised by any academic scholars in the field. Only by fundamentalist Christians " ? If the gospels used scripture of Paul... Why do you think Gospelwriters did not use Paul's scripture?
  13. Did Christianity start with a real human Jesus?

    There you go again with your "majority view". It's meaningless. And it's very often self perpetuating. After all, who is teaching the new crop of historians? People who hold the "majority view". It's a bit like the Christian religion itself. It's self replicating down the ages. And climate research IS a good example of a self perpetuating consensus. Nobody in their right mind would go into climate research, if they didn't already believe in MMGW. They would just be signing up to a lifetime of being shunned, and unemployable. Unless they were prepared to keep their mouth shut and live a lie. Climate research is now for believers only, and that's pretty close to bible history too. It's nice to see one or two dissenters, but they need to be pretty special people to make a go of it.
  14. Presidential Alert system

    I have been curious what the impetus for this was. If it is something long digesting or something Trump asked for.
  15. Which is more accurate when calculuating current/voltage/resistance?

    As far as I can tell, I have to congratulate you on either your mind reading, or your time travel, since the OP has yet to explain what those needs are. However, to kick the issue back to the topic. There wouldn't have been a debate if you hadn't muddled up sensitivity with precision... Yes; we do, but it's got nothing to do with the topic. However, once you introduced it I felt it was sensible to point out why you were mistaken in thinking that "Chemists often work in parts million" in some way invalidated my point. Fundamentally, somewhere along the line, someone has to do the measurement. You can often rely on the manufacturer to do that well enough. If you don't like the E24 series, you can pay more, and get better precision.
  16. Presidential Alert system

    If one person in 10 switches the TV on "to see what's happening" that will be a big power spike. If it knocks the power grid out (even locally) and that causes something important to fail (traffic lights would be an obvious possibility) then Trump's vanity project will kill people. Are there any Trump supporters here who would like to comment on why they think he' doing a good job?
  17. Moving clocks.....

    I still don't see how this leads us to a clock the measures time not time difference. There are many quantities in Science that we (only) measure by difference, including distance. Surely this must be so as there is no absolute axis of time or distance. This is fundamentally different from say temperature where for instance the freezing point of water is a particular point on the scale and no other in whatever units you choose to measure. Another such 'absolute' would be the number of neutrons (or protons or electons) in a given isotope. Or perhaps Avogardo's Number.
  18. Moving clocks.....

    And I'm saying that you aren't using them to "tell time" in those experiments. You are comparing two clocks, not reading the results of one clock. And there are relativity experiments where you don't "zero" the time since you do a frequency comparison rather than a phase comparison.
  19. Natural response of RC and RL Circuits?

    You have to understand what the transistors do in the circuit. Here, they are acting lie switches. The three connections to the transistors are as follows; At the top we have the collector, at the bottom is the emitter and out the side is the base. Basic operating principle is this: If a small current flows between emitter and base, then a larger current will flow between emitter and collector. Current will not flow between emitter and base unless the base-emitter voltage is above a certain threshold call the bias voltage. So let's assume that Q1 is presently conducting. At this point, C1 has been charged to a positive voltage at the plus sign. With Q1 conducting, this end is pulled to zero, which pulls the other end negative, which in turn drives the voltage at the base of Q1 negative and below cut off. Q2 does not conduct. This means that C2 will now now start to charge Through R4. Meanwhile, C1 is discharging, which causes the voltage at the base of Q2 to go more positive. Eventually it reaches the point where Q2 starts conducting. This drives the positive end of C2 to zero and the base of Q1 negative, shutting off Q1. C1 now begins to charge through R1 while C2 discharges. Eventually C2 discharges enough to turn Q1 back on and we are back to where we started. The speed at which the capacitors go through their cycles depends on the the time constants of C1-R2 and C2-R3. (its possible to use different time constants so that one LED remains on for a larger percentage of a whole cycle than the other does.)
  20. Truth About Corners

    I can tell you where they most probably would be, but luckily exactly. We can now think of schizophrenia as a disease of the mind from time spent in theorizing the subject matter, that has grown wrongly. A subliminal theory arises, and if not thought correctly, which is genetically in some cases, it causes waste product to develop of unnoticed truth. I am always lost in spiralling rhythm, therefore, there is a neutral rhythmic which I am not noticing and forethought is noticing it...
  21. Truth About Corners

    You have a theory? I had no idea. Great. Can you tell me where I left my car keys? (And please don’t say, “in the corner”)
  22. Truth About Corners

    What's good about this theory is that it opens a vestige of knowledge in human psychology, more problems than ever before are now more easily solved.
  23. Natural response of RC and RL Circuits?

    Yup that's it. And yup there are many types these days. What about the other components? That book (by Tooley) I mentioned back along uses these and offers practical advice like I gave with the caps. You will need this for the LEDS and transistors. Do you know anything about the ones on the diagram?
  24. Explanatory power

    So what does that essay title means to you ? I would say it should distinguish between what Science can and cannot explain and say why. But check with your tutor/lecturer that you and she agree what you are going to write about, it is a very loosly defined title.
  25. Natural response of RC and RL Circuits?

    Yeah I think it is solderless board and you can just use wires to insert into them. They are really cheap on Ebay.
  26. Moving clocks.....

    I don't know I was asleep at that time (date). Which is why I asked why experimenters have to zero their clocks if their clocks tell 'the time'.
  27. Explanatory power

    Good day ; Yes I mean to post it; Context: philosophy of science home work Philosophy of science, 1 credit, Each student should independently write an essay on philosophy of science. pick your question and respond on it in relation to the literature. The essay should be 500-1000 words
  1. Load more activity