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About druS

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  1. Same as studiot. Note that most domestic solar panels don't deal with partial shading at all. It de-rates many systems so that the whole panel may as well be in the shade. There are commercial systems that have dealt with this issue but I doubt they are easily available for domestic. Height itself makes no difference. Angle to the sun obviously does.
  2. Overlapping orbitals of electrons

    Guys, I thought I should revisit my thanks here. You give a perspective that simply doesn't come from a uni subject on basic chemistry. Hey, you offered me a quantum physics "rabbit hole" to chase. And I appreciate it. In time, in time. Right now an issue I had in Chemistry has evaporated. Go to to say thanks, no honest really thanks, for that.
  3. Overlapping orbitals of electrons

    Cheers Swansont
  4. Overlapping orbitals of electrons

    Thanks guys, as usual dropping questions here leads to interesting discussions I had not considered. Note that (at this stage) my studies are chemistry, not quantum - though without doubt this is starting with "sub atomics" and in particular the actions of the electron. [clearly moving toward chemical bonding.] This said - swansont, if Pauli exclusion relates to energy and spin (can I leave out orbital angular momentum for now?), the the 1s and 2s orbitals (for example) can never be other than excluded as they are different energy levels to start with? This would cover the matter for all orbitals that appear to share space/volume. In terms of "position is not a quantum state" my visualisation gets caught again - what happens when molecules - or make it simpler, two monoatomic elements meet. More specific, noble gases so we are not dealing with bonding complications. The electrons simply don't notice the orbital space of the other when they "rub shoulders"? studiot I must be reading those diagrammes incorrectly - Fig 9 seems to me to clearly show the 1s and 2s orbitals overlapped. Or that their is a probability of the 2s orbital with an electron positioned (that word again) in the 1s orbital probability.
  5. Guys, I'm having trouble with another really basic concept so I hope you can sort me out. Let's just look at the spherical orbitals. In the usual diagrams the 1s orbital completely is inside the 2s orbital. But Pauli excludes this. Is the 2s orbital actually a sphere with a (1s size) hole inside of it? This overlap can be carried through to the 2p etc orbitals. In a massive atom that inner sanctum of 1s volume, against Pauli, could get very busy. Cheers
  6. The effect of additional neutrons

    Now that is interesting though have to say beyond my current knowledge ability. So we create a new nucleus by forceably removing a neutron proton [self edit]. Presumable the "un-required" electron simply matches?
  7. The effect of additional neutrons

    Thanks guys - apologies at not responding earlier - we've had some family health matters that changed my focus for a bit. Int ereseted in the comment that a nucleus being a soup of quarks - sounding like an modern update on the plum pudding model of the atom. (Ok, not really but interesting anyway.) Are their any thoughts on "why"? Why does carbon do C12 and C14, for instance?
  8. I'm trying to fathom what is happening when an atom has additional (or fewer!) neutrons than the number of protons - different atomic isotopes. Generally I understand that chemical properties are set by the quantity of protons/electrons and the relationship or "closeness" that the electron orbit has to the valence electrons. (Happy to have my clumsy language corrected). Why does/can a nucleus adopt additional or fewer protons - at all? Then it seems to make a little sense that the more massive nucleus might have "space" for additional protons - why does it happen with hydrogen? What are the differences in chemical properties for different isotopes and why? I understand as an overview, there are no practically discernable differences in chemical properties, albeit there is radioactivity in the larger isotopes. In detail however, that isn't the answer is it? In Hydrogen, between 1H, 2H and 3H there is an incredible proportional difference in atomic mass of 200% or 300%. I have read that reaction times can be different. Anything else?
  9. Humidity and Health

    OK, Studiot, as usual is completely right, a bit of heat will go a long way in these circumstances. At near freezing, I'd suggest opening the window will do naught. BUT, if there is a human inside breathing, you have a little humidifier in the system in these conditions. Mate I haven't experienced this much personally, one though a trip where I crossed the arctic circle in winter, and that same trip further south in very cold conditions. Sleeping in a car north of the acrtic circle in winter my breath was easily creating enough humidity that I had freezing on the windows inside the car. Opening the windows solved the issue. OK down to say -5 but if it's getting colder live with the frost. Try a little heater, but at near freezing it doesnt need much breathing to create high humidity. Nor does it need a lot of heat to solve it.
  10. Well no, and I would have assumed in celebs that it wasn't natural. Of course there is racial harmony and mixing these days, but that would be a different issue wouldn't it>
  11. So previously known/proven? Still they seem have shown this through the genome which is amazing. Black skin blue eyes would look odd today!
  12. Humidity and Health

    The effect of air flow: If your campervan is indeed 80%RH, and outside is say, 40% - opening the windows will certainly help. But it is not because airflow is impacting humidity, is because you are replacing the humid air with drier air. The human body moderates temperature by radiation and as it gets hotter by evaporation - sweat. If we have a hot humid environment, the air does not have much capacity to take up a lot of moisture. The boundary layer (for want of a better term) close to the skin becomes saturated. In this case, air movement will help, because new air is dryer than the old boundary air (even if it is humid). So evaporation is more effective. If it is a dry heat then air movement wont do anything - for practical purposes. If it is cool and humid it also wont pick up a lot of moisture because the max vapour pressure of moisture is low - even if it is cold and dry it doesnt have the capacity to pick up much moisture. A heater will work if the source of the humidity is simply the internal air. If you have an independent moisture source, say something got wet - the heater wont do much. Think about hiring a small dehumidifier. It's like a small air-conditioner but has a set point below the due point to extract moisture. They can be quite effective. Maybe run it for a week then return it.
  13. The Baddest Bridge Near You

    Sydney Harbour Bridge. No doubt there are plenty of claims for "longest span" and the like, wiki says it was the Harbour Bridge until 2012. Prototype built in Newcastle UK (I think), the final version was inspired by Hells Gate in New York. Completely dominates Sydney harbour and is an annual focus each New Year's Eve.
  14. Humidity and Health

    Ifit If the partial pressure of water vapor in air approaches 100% (ie we approach 100% RH) water will drop out of the air. The easiest way to force this is by cooling. If it is -3 the water drops out as ice. Snow or hoar frost or ice crystals etc. If it is above 0 it is dew, or rain, or mist, etc. The device used to work out air temperature/moisture vapor/condensation etc is the psychrometric chart. They are not hard to find on the net, and it is reasonably self evident how to use the thing. As a note, if it is cold and humid, we tend to describe it as "clammy". Hot and humid as "muggy". I'm not sure of the health issues you are looking for, and it's not an area I have any more info than the uninformed. Humidity and de-humidification is something I might be able to help with. Sometimes it's done with dessicant crystals, ie direct absorption, but the traditional method is to over cool the air well below dew point where the moisture condenses and drops out as condensation, dew if you prefer (so there is a lessor absolute quantity of water vapor in the air, even though it is 100% RH) then re-heat it. With less water vapor, the RH has reduced. It's pretty energy inefficient. Oh, the effect of wind movement is a different thing again, but generally impacts perception rather than the actual "humidity". I can run through that if that is what you are looking for.
  15. Vibrational Frequency CO2 Global Warming

    Studiot Hope you are still happy to talk on an old thread. Let me try to pull together what I think I have picked up so far. A molecule's reaction to EM depends on it's structure, shape and bonding. CO2 is a linear molecule so it's vibrations are waggling and stretching. These motions make it unresponsive to the visible spectrum but responsive to IR. Non-linear molecules don't react to IR (but do react to visible light?) - which covers water. I would however have thought that nitrogen and oxygen were also linear? Specifically to CO2 there are three frequencies - am I reading that graph correctly? Asymmetric being something close to 3900-3400; symmetric 2400 and bending 900? Can those frequencies be related to the vibration modes called waggling and stretching? I follow part only on the resonance discussion - the aerial analogy doesn't help me as my understanding of an aerial is as rudimentary as molecular vibration. Though I note the discussion that the increased energy is not related to electron states - without following this too closely, it would then relate to movement between parts of the molecule - ie the bonding. Anyway, hope you have your red pen ready. [ps to the many other posters here, I am not ignoring your content which has also been very interesting. Fire away at will! I am just going to avoid flights of fancy such as arguing about waves in the in absence of a medium, etc. Studiot has laid out a path that connects with me is all.] EDIT: in the chem tube pictorial of CO2 vibration, the graph indicates several specific levels that I take to be energy levels ie VB = 0; v = 1; v = 3; Dissociation. I had thought this to be like electron energy levels, in steps, but clearly NOT electrons. Do the vibrations come in energy steps also? And does dissocation mean what it says? I would have that would require extraordinary energy but the step doesn't look huge.