593 reputation
210
bio website dropletsforming.blogspot.com
location England, United Kingdom
age 31
visits member for 3 years, 7 months
seen 2 days ago

Jul
10
comment Classic home experiments for an 8-year-old child
Exactly. That's one of the things that I feel makes for a good learning experiment; there is space for multiple hypotheses, and people usually get it wrong the first time. I remember being sure it would miss, partly because it seemed impossible to hit it every time. Ping. Clatter. Gasp!
Jul
9
comment Classic home experiments for an 8-year-old child
Yes. The narrative is intended to point out that the gun is pointed directly at Kiki. The usual intuition mistake is to assume that bullets do not fall like any other projectile, or to ignore it. The set-up with the monkey letting go as the gun fires is supplying a separation of the motion vector. Clearly for a real gun to function correctly, its targets must compensate for the motion of the bullet.
Jul
9
comment Would a craft travelling increasingly close to the speed of light appear to be decelerating?
True, and this is the basis of many 'paradox' explanation articles. The question, however, was how it would appear to an observer, not to the traveller. To the observer watching someone accelerate near c, it is still an acceleration. Just because you move at some speed relative to me, it does not change my experience of time.
Jul
4
comment Does serving food on a hot plate really keep it warm longer?
Extract from the lab diary: "Trial 1, Apparatus: Roast chicken dinner (plate at 21.3deg), dining table, knife and fork..."
Jul
1
comment Effective mass of a particle
It can also be anisotropic (for example in Silicon)
Apr
9
comment Force between two charged particles
To clarify, do you have 2 charges (q0 and q1) both on the y axis, separated by distance d1?
Apr
8
comment multibody problem and determinism
I'm not confusing them, they are the same thing. We see from the double slit experiment that making the result deterministic changes the very probabilities of the evolution of the system. I'm probably not explaining it very well. Many worlds just says that the mechanism of multiple states evolving simultaneously is deterministic; i.e. the universe bifurcates at every instant. But it does not give an answer on how or why recombination happens. Yet some prefer it because it takes one of the question marks away (at the cost of adding an infinitely bifurcating universe).
Apr
8
comment multibody problem and determinism
I would say it is generally accepted. As we can only falsify non-determinism (i.e. we cannot prove that something has no cause, only that none has been found), there will always be some who dislike the idea of something unseen deciding whether the cat lives or not. However, unless you are in the field of many-worlds theories and so on, it is immaterial what you believe; the equations give you the non-determinism you will have to deal with. The most broadly accepted interpretation (Copenhagen) is that we do not know what happens in the midst of an interaction, only that it follows our equations
Apr
8
comment Does interference take place only in waves parallel to each other?
@rahulgarg12342: Hmm. The first is meant to show how the path difference varies over the plane, and the second is supposed to show how that results in reinforcement or dampening of the resulting waves, including where the dead zones are. If you understand that, how would you describe it? If not, how far do you follow it? Cheers!
Apr
8
comment Does interference take place only in waves parallel to each other?
@rahulgarg12342: Is the edited answer understandable? When you say 'interference', do you mean destructive (cancelling out) effects or constructive (reinforcing) effects? Interference really covers both, it just means a pattern resulting from two waves interacting.
Apr
8
comment Does interference take place only in waves parallel to each other?
@ParthVader: I had gone down a bit of a rabbit hole, but hopefully the edited answer is a better fit.
Apr
7
comment Does interference take place only in waves parallel to each other?
I've added something hopefully clearer at the top, might get a chance to illustrate it a bit later.
Apr
7
comment Does interference take place only in waves parallel to each other?
I'm saying that as you slide one wave next to the other, you increase the phase difference and go smoothly from making the wave bigger to making it smaller and eventually zero. Moving it further it becomes bigger again, in a cycle.
Mar
12
comment How do we perceive colors outside our gamut?
I see what you're saying now, I didn't get any of that from the answer. Also interesting might be perception of blue without perceiving red, as red cones have a blue peak as well; this could be what we call violet.
Mar
12
comment What is the limit to how many satellites can orbit the earth?
The GEO satellites are running around the equator, and so are some of the other satellites. Most non-GEO satellites, however, have a different inclination, because the geostationary bit is the main reason to put a satellite above the equator. At low orbital altitudes, the satellite is visible for a smaller area of the Earth's surface, so to reach the majority of users in the northern hemisphere (North America, Europe) they have to have a higher inclination to be any use. These satellites are then less useful for much of their orbit.
Mar
12
comment How do we perceive colors outside our gamut?
@MSalters: Ok, I can believe that there is more to it than independent cone saturation, but regardless of why they are firing or not firing, the signals come from your existing cones, so the brain interprets them as colours just as if there was a light of that colour. My point is that after-images just produce other colours from the same gamut.
Mar
11
comment Why the quantum entanglement doesn't break quantum cryptography
@PeterShor: Looks like an answer to me.
Mar
11
comment How many quarks in a proton?
This answer seems reasonable, but perhaps clarify that the infinite quarks are merely probabilistic and temporary. The three stable quarks are the only ones with any importance outside the hadron.
Mar
11
comment Differential Forms and Densities
Integrating over a volume of a charge density will give you a charge. To get mass you would need the density itself (rather than the charge density). So unless you know some relation between charge and mass, e.g. that only electrons inhabit the space and thus go charge density->electron density->mass density, you don't have the right information. Is it a different kind of density you are expecting?
Mar
11
comment How do we perceive colors outside our gamut?
I believe afterimages are simply a result of saturation of the cones, and the resulting lag in their response to intensity changes. The colours you see in an afterimage are still just some combination of red, green and blue, so although it looks strange, it is probably reproducible.