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| bio | website | |
|---|---|---|
| location | Netherlands | |
| age | 39 | |
| visits | member for | 2 years, 6 months |
| seen | Apr 21 at 23:23 | |
| stats | profile views | 58 |
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Apr 19 |
comment |
Is speed of electrons in atoms a constant during explosions? After an explosion, of course all kinds of particles will be flying away from the centre of the explosion, including electrons. That's obviously a change in their speeds. But your question probably hinges on the speed vector versus the absolute speeds. |
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Apr 19 |
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How do forces work For electro-magnetic forces, we can say "photons", but is that really a better explanation than "force fields"? At least "photons" correctly imply quantization, but I don't think that was your objection against the term "force fields". |
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Mar 15 |
answered | Why is visible light used in Optical fibers (instead of other EM waves)? |
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Mar 12 |
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How do we perceive colors outside our gamut? @PhilH: You're still assuming that any brain input could have been created by light of a specific color. That's not true. Simplified: if the R sensitivity at G wavelengths is still 0.1 relative, a brain input of R=0, G=1 cannot be created by pure green light but only by first saturating the red cones and then watching a pure green light. That would be "greener than green" as mentioned in the answer above. |
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Mar 12 |
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How do we perceive colors outside our gamut? @PhilH: The R/G/B receptor response curves are not orthogonal, which means that some extreme responses can only be caused by saturating some cones. I.e. here it seems the blue cones are saturated, and then the green surroundings don't trigger them at all. |
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Jan 5 |
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Is there something special in the visible part of electromagnetic spectrum? @dmckee: That still is a tiny part of the EM spectrum. From VLF to gamma is 14 orders of magnitude; the biologically observable part is about one order. To summarize: from heat to molecular destruction. |
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Dec 7 |
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What matter in the original atom bomb is converted to energy? I'm a bit hesitant about your first sentence. Obviously you can't vanish mass when that would violate conservation laws, e.g. you can't make an electron vanish because its charge must be conserved. But particle-antiparticle pairs are just one way to balance conserved properties. |
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Nov 10 |
awarded | Yearling |
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Oct 11 |
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Why don't electrons crash into the nuclei they “orbit”? @Zeynel: he both says that "particles are quanta" and "quanta are not particles". The wave/particle duality is well-established and dates back to 1924. Only in fringe theories are they considered distinct. |
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Oct 10 |
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Why don't electrons crash into the nuclei they “orbit”? @Zeynel: He makes a mess of terms. See the 1st URL you posted: .../7-particles-are-quanta. |
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Oct 9 |
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Why don't electrons crash into the nuclei they “orbit”? @Zeynel: I don't agree with (2). As you see, he talks about fields. Fields are quantized, and the unit is a quantum. A field is not a wave, just like it's not a particle. The quantum has properties, such as electric charge. |
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Oct 7 |
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Why don't electrons crash into the nuclei they “orbit”? @Zeynel: The two terms are interchangable. Sometimes you observe particles. Remember the clicking sound of a Geiger counter? Each click is an the detection of a particle. I'm calling them "particle" here because it's a quantum of energy, so particle math is easier. But at the same time it's a wave. |
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Jul 31 |
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Can gravity be absent? If you look globally, any universe with mass will have non-zero gravity somewhere. Locally, the question is indeed more interesting. Within that cavity, for example, is there anything you can tell about the gravity outside the cavity from the (lack of a) field inside? |
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Jul 31 |
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Can gravity be absent? What about the middle point between two identical objects? There would be no net gravity field there, and I am wondering if that situation (no net gravity) can be physically distinguished from the situation where there is no gravity at all. |
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Jul 19 |
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Does gravity slow the expansion of the universe? @AlfredCentauri: That's the question here! I don't have a background in astrophysics, so I can't give a good answer. |
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Jul 17 |
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How can you measure battery output to see if the wattage is accurate? This assumes ΔV is constant over time, which isn't precisely true. (It depends mostly on battery chemistry) |
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Jul 17 |
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Does gravity slow the expansion of the universe? @AlfredCentauri: Does that really matter? "If spacetime isn't curved , would the universe expand faster?" is essentially the same question. |
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Jul 13 |
answered | Why does the note played by a flute not change in this case when the air column is interrupted? |
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Jul 7 |
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Physics of Fireworks @dmckee: I'd agree with those comments; for a regular fire that's probably the case. But fireworks use selected metals (e.g. Potassium, Lithium, Calcium) to achieve the desired colors, and those ionize far easier. See also chemicalforums.com/index.php?topic=3553.msg15479#msg15479 |
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Jul 5 |
answered | Physics of Fireworks |
