Ask any question you want about Physics

originally posted by: Nochzwei
If you missed it, I had explained earlier , electric sources are not good. Voltage/current self limiting, due to resistance /temp changes.

It doesn't make any sense that you're concerned about temperature changes with electric lights but not with candles. Measuring the effect of temperature on candles is a 7th grade science fair project and I mentioned this before. Lots of chemical reactions proceed more quickly at higher temperatures, such as combustion, so temperature can affect candle brightness.

Does a Candle's Temperature Affect its Burn Rate?

a reply to: ErosA433
So the frequency of the color was measured, and if so any idea of measurement uncertainty/tolerance?

That's an interesting scenario. If the density of the Earth was homogeneous and you made accurate enough measurements you might be able to measure some kind of change. But of course the density of the Earth isn't homogeneous, as it has a dense core.

As you descend you have two opposing factors trying to affect gravitational acceleration in opposite directions, and they may just about cancel each other out:
1. All the material above your head is pulling the opposite direction from the Earth's center which should lower "little g".
2. You're getting closer to the denser core, which should increase "little g", where "little g" = Earth's gravity.

The net effect of those two might cancel out so you might not measure much change in "little g" for the first 1000-2000 km of depth below Earth's surface, but of course we've not gone very deep and I haven't tried to research if precise gravitational measurements have been made underground support this model. It may even depend on the local geology. Even if you could measure a frequency change in the light with a precision instrument, I think it would be hard to see a color difference with human vision, but of course this applies to a 2m height change above the surface also.

You got there before me, i was going to say the same thing...

power supply compensates for different things = not valid
candle properties change, compensating for temperature and extra fuel supplies = the same as above, but is valid....

I dont get the logic there

The wavelength of the laser diode was not monitored, so i cannot say, but that said, we did actually have 3 calibrated heads of wavelengths 375, 405 and 445nm,,, and we did actually take optical measurements sensitive to wavelength, and no detectable wavelength change occurred for optical components (taken with a DSLR) now I wouldn't count this as being a true wavelength measure, the fact that the relative intensities of the signals under the green/red/blue filters kept the same ratios indicates no significant shift of outlying wavelengths. Not accurate though and im not going to suggest i know the wavelength to better than a couple nm

originally posted by: [post=19932395]Arbitrageur

It doesn't make any sense that you're concerned about temperature changes with electric lights but not with candles. Measuring the effect of temperature on candles is a 7th grade science fair project and I mentioned this before. Lots of chemical reactions proceed more quickly at higher temperatures, such as combustion, so temperature can affect candle brightness.


So?

originally posted by: ErosA433
You got there before me, i was going to say the same thing...

power supply compensates for different things = not valid
candle properties change, compensating for temperature and extra fuel supplies = the same as above, but is valid....

I dont get the logic there

Lol if resistance increases a steady voltage source will deliver a lower current. isn't it?

originally posted by: Nochzwei

originally posted by: ErosA433
You got there before me, i was going to say the same thing...

power supply compensates for different things = not valid
candle properties change, compensating for temperature and extra fuel supplies = the same as above, but is valid....

I dont get the logic there

Lol if resistance increases a steady voltage source will deliver a lower current. isn't it?

And what makes you think the resistance on a wire will increase depending on hieght? Because this would be huge nees when building sky scrapers. Now in producing DC current you need to take altitude in account because batteries use air as a dielectric. The thinner the air the less insulating properties it has but even with that its like a pube 3000 ft if I remember. And what does resistance have to do with color change in light. If you calibrate your light source doesn't matter in the least what produces it.

originally posted by: dragonridr

originally posted by: Nochzwei

originally posted by: ErosA433
You got there before me, i was going to say the same thing...

power supply compensates for different things = not valid
candle properties change, compensating for temperature and extra fuel supplies = the same as above, but is valid....

I dont get the logic there

Lol if resistance increases a steady voltage source will deliver a lower current. isn't it?

And what makes you think the resistance on a wire will increase depending on hieght? Because this would be huge nees when building sky scrapers. Now in producing DC current you need to take altitude in account because batteries use air as a dielectric. The thinner the air the less insulating properties it has but even with that its like a pube 3000 ft if I remember. And what does resistance have to do with color change in light. If you calibrate your light source doesn't matter in the least what produces it.

resistance of light emitter or bulb increases with its rise in temp.

a reply to: Nochzwei
Resistance of the filament in an incandescent lamp goes up as a function of temperature, true.
However...
Resistance of a LED goes down as a function of temperature.

a reply to: Nochzwei

you are somewhat ignorant of the fact that a laser diode, is not a simple wire and resister chain connected to a battery.

It is possible to achieve a very accurate pulse to pulse or DC offset that does not change systematically more than 1-5% per pulse.

And your logic is once again flawed... we said that temperature will affect these things and yet you deny its importance when considering a candle. Laser Diodes include cooling and temperature monitoring. I would say with a high degree of confidence that once a laser head has been operational for a short period and the equipment is at thermal equilibrium, and variation of the output is going to be insignificant in comparison to that of a candle. Not only this but by your theory if time dilation is to work as you think causing a frequency shift, then you can simply perform this experiment by pointing the laser and detecting it at different heights...

Not only that but typically these devices include temperature monitoring and control as part of the package. In our case we used the device in almost identical environments with almost identical temperatures.

Let me lay it out for you

LEDs
1) you are against electrical devices because, you believe by changing height, it will change the power requirements and power supplies are built to compensate any such changes
2) Temperature stability changes the properties of the LED, and as the device warms, it will have different properties, and some will be none trivially altered by the effects of point 1, feedback if you will.
3) If you wanted to test your theory with an LED you should simply measure the current or the temperature and see if it runs hotter when up higher...? Thus determine the different experimental effects... wait this is starting to sound like ACTUAL experimental science, something which is in huge contrast to your candle routine.

Candles
1) We are against candles for exactly the same reasons, you believe by changing height something fundamentally changes, time dialation etc, which means the candle burns brighter... you like candles because you do not believe the are affected by the two points named above in the LED section
2) The candle is a combustion device, it works by creating heat... and it is known temperature is a driver of the brightness of the flame
3) Local oxygen concentration (which will change) can change the brightness of the flame.
4) consumption of the wick is not constant and the fuel feed to the combustion point is highly variable depending upon geometry.
5) All of these are hard/impossible to quantify


So you dont like LEDs because you can actually quantify them and you do like candles because you cannot actually quantify them.... see where i am going?

originally posted by: Nochzwei
resistance of light emitter or bulb increases with its rise in temp.

No, see Pirvonen's reply.

The question you haven't answered is:
Why are you concerned about thermal effects with electric lights but not with candles?

Atmospheric temperatures are not homogeneous, and sometimes you get a layer of cooler air close to the ground, either indoors or out. Temperature versus height in my house varies depending on time of day. When my attic is hot the ceiling is giving off heat, but when the attic is cold the floor is giving off more heat then the ceiling.

Outdoors if you have any breeze or wind blowing, that's a result of temperature not being uniform and also makes it even more difficult to gauge light output from the candle as it adds a variable.

originally posted by: Pirvonen
a reply to: Nochzwei
Resistance of the filament in an incandescent lamp goes up as a function of temperature, true.
However...
Resistance of a LED goes down as a function of temperature.

Correct on both points. This pdf shows the relationship of LED resistance versus temperature if anybody wants to see a more detailed characterization of the relationship.

So while both electric lights and candles can vary with temperature, there are ways to apply tighter controls to electric circuits with voltage or current regulators so electric lights can operate stably once warmed up to operating temperature. However candles have no voltage or current regulators, so they are more at the mercy of temperature variation, and in the case of "The Ark" video they are also subject to varying breeze conditions.

Not that I like candles but have easy access to them compared to leds and current measuring devices. besides the changes in an led output may not be easily perceptible to the human eye, whereas changes in flame of a candle is perceptible to human eyes. yes candle that burns brighter is hotter, so what? its the after effect of time dilation.
now if you want to perform a simple but precise expt, as suggested earlier, take a sunlight spectrum on the rooftop and at ground level and report which one comes out blue shifted , but you do need a spectrometer.
a reply to: ErosA433

originally posted by: Nochzwei
Not that I like candles but have easy access to them compared to leds and current measuring devices. besides the changes in an led output may not be easily perceptible to the human eye, whereas changes in flame of a candle is perceptible to human eyes. yes candle that burns brighter is hotter, so what? its the after effect of time dilation.

This "my candles are a better test than hundreds of precision experiments using calibrated test equipment" nonsense is getting old. I'm glad you have easy access to candles but a clock is what measures time so if you want to make a conclusion about time dilation you need some kind of clock. A frequency counter measuring the shift of a monochromatic light source might work if the time dilation was large enough, but the experiments being proposed have only small time dilation effects so the Pound rebka experiment used used gamma rays with higher frequency than visible light where it's easier to detect small differences in frequency. In a height difference of 22.6 meters the expected and observed gravitational redshift was only 4.92 x 10^-15.

now if you want to perform a simple but precise expt, as suggested earlier, take a sunlight spectrum on the rooftop and at ground level and report which one comes out blue shifted , but you do need a spectrometer.

Again the predicted redshift/blueshift effect will be very small, and too small to observe with an ordinary spectrometer unless you were an exceptionally clever experimentalist with some neat trick to observe such a small change on visible light, but your preference for using candles as measurement devices in experiments doesn't paint you as a clever experimentalist.

Did you do this experiment and what kind of shift did you observe? How you're going to see a redshift of 4.92 x 10^-15 over 22 meters with visible light from the sun going through a spectrometer is a mystery. That's a very tiny redshift.

The sun is about 333,000 times more massive than Earth, and even the sun's gravitational redshift was difficult to measure with visible light, and wasn't done until 2012 as far as I know:

Detection of Gravitational Redshift on the Solar Disk by Using Iodine-Cell Technique

originally posted by: Nochzwei
[You got it backwards. GR is wrong. But they will not teach you this in the universities. So I don't blame you really

Who said I went to a university? Do you know that there are PHD thesis papers and such that come out all the time with all sort of alternate theories to standard theories in physics?

GR isn't "wrong" because it describes accurately things about the real world. It describes Newtonian gravity and it goes further to make finer detail corrections that classical gravity cannot account for.
So it is correct. Even if it turns out that the geometrical interpretation of gravity isn't a literal truth.

What do you feel is wrong with it?
The washing machine experiment expresses no anti-gravity so you can't use that.
If you want to use a candle to show anti-gravity this is what a candle would do outside of the Earth's gravity.

www.theatlantic.com...


Still, if someone claimed to cancel the gravity acting on a candle (completely cancel) why wouldn't it be able to float weightless?
Also, like Arbitrageur said the Earth does not bend light enough to notice. Do you even know what GR predicts?
Gravitational lensing happens with much heavier objects that are in between the light source and the telescope.

originally posted by: Nochzwei
ques: Since gravity on the moon is much less, Will any of our nuclear device explode on the moon, if tried?

They blew up several nukes in space. Nothing is different except the explosion makes a circular fireball.
It's fissionable material surrounded by explosives which create a fission explosion that is forced into another chamber with some elements where fusion happens briefly.

The process doesn't change with any type of time dilation because locally you can't tell there is time dilation. Everything is normal from the perspective, everything else will seem to be faster/slower.

originally posted by: Arbitrageur

originally posted by: Nochzwei
Not that I like candles but have easy access to them compared to leds and current measuring devices. besides the changes in an led output may not be easily perceptible to the human eye, whereas changes in flame of a candle is perceptible to human eyes. yes candle that burns brighter is hotter, so what? its the after effect of time dilation.

This "my candles are a better test than hundreds of precision experiments using calibrated test equipment" nonsense is getting old. I'm glad you have easy access to candles but a clock is what measures time so if you want to make a conclusion about time dilation you need some kind of clock. A frequency counter measuring the shift of a monochromatic light source might work if the time dilation was large enough, but the experiments being proposed have only small time dilation effects so the Pound rebka experiment used used gamma rays with higher frequency than visible light where it's easier to detect small differences in frequency. In a height difference of 22.6 meters the expected and observed gravitational redshift was only 4.92 x 10^-15.

now if you want to perform a simple but precise expt, as suggested earlier, take a sunlight spectrum on the rooftop and at ground level and report which one comes out blue shifted , but you do need a spectrometer.

Again the predicted redshift/blueshift effect will be very small, and too small to observe with an ordinary spectrometer unless you were an exceptionally clever experimentalist with some neat trick to observe such a small change on visible light, but your preference for using candles as measurement devices in experiments doesn't paint you as a clever experimentalist.

Did you do this experiment and what kind of shift did you observe? How you're going to see a redshift of 4.92 x 10^-15 over 22 meters with visible light from the sun going through a spectrometer is a mystery. That's a very tiny redshift.

The sun is about 333,000 times more massive than Earth, and even the sun's gravitational redshift was difficult to measure with visible light, and wasn't done until 2012 as far as I know:

Detection of Gravitational Redshift on the Solar Disk by Using Iodine-Cell Technique

my theory is to use em wave as a yardstick to measure time. Radioactive sources are hard to come by, so em wave is the next best thing. clocks are not good, as in time dilation the ceasium atom/and or the associated electronics will put out a higher freq. and hence the clock will erroneously show faster time. well this is only common sense, isn't it?
Pound rebka expt is a load of bunk to keep gr dogma alive. Instead my proposal of sunlight spectrum is better for 22.6 m of height difference.
Clever experimentalist? Do you not understand English? Candles are being used because of easy access only for lack of access to precise instruments and sources.

a reply to: Nochzwei

Please give me a prediction of the blue shift of the sunlight dependant upon height. I can then tell you if any measurement even possible.

1) 2 meters
2) 2.1 km

I suspect... none observational but since you are the one of understanding here Nochzwei, please give predictions.


Experimentalist yes, but you deflect... first we might possibly have convinced you of the flaw of using a candle, and now you just propose a different measurement (which has already been done over a greater distance than 22 meters with other equipment)...

ask iss astronauts to take one and you take one at ground level and compare and report. If I had the necessary instruments or a radioactive source and counter, I would be able to calibrate ambient time vs mans clock time and give you a quantitative prediction. till then we are stuck with qualitative results only. hope that helps
a reply to: ErosA433

originally posted by: Nochzwei
ask iss astronauts to take one and you take one at ground level and compare and report. If I had the necessary instruments or a radioactive source and counter, I would be able to calibrate ambient time vs mans clock time and give you a quantitative prediction. till then we are stuck with qualitative results only. hope that helps
a reply to: ErosA433

www.nature.com...

Put it all in a post if you can, rather than just a link, without your twist or take on it..
a reply to: dragonridr

originally posted by: Nochzwei
in time dilation the ceasium atom/and or the associated electronics will put out a higher freq. and hence the clock will erroneously show faster time. well this is only common sense, isn't it?

It's a double negative.

You say time dilation=faster time
You say relativity has it backwards

But time dilation means time is slower by definition, not faster, so since you have that backwards and you think relativity is backwards maybe you're in agreement with relativity after all.

It's hard to make sense out of contradictory statements like "time dilation is faster time". It's basically nonsense, not common sense.

But yes as time slows down, frequency increases which is why the pound-rebka experiment did what it did. However you seem hopelessly confused between time and frequency going in opposite directions, and talk about time dilation correlating to faster time when frequency increases, but it's the opposite of that; time is slower as frequency increases in gravitational blue-shifting. You just misunderstand basic concepts and basic definitions of terminology like "time dilation".

originally posted by: Nochzwei
Put it all in a post if you can, rather than just a link, without your twist or take on it..
a reply to: dragonridr

I hardly see the point in explaining it since it's one of the hundreds of careful experiments and observations confirming the predictions of general relativity, and you will just point to two uncalibrated candles as evidence those hundreds of calibrated experiments are wrong. The Pound Rebka experiment was explained and all you said was "it's bunk"; you didn't state specifically how they should have performed the experiment differently.

Yes and the point i personally was trying to make is that if a distance of 2 meters is observable, then it would be common knowledge that aircrafts flying much higher than 2 meters would have to take into account the fact that all their radio and infra red equipment would simply not work or be recieved at a different wavelength than expected on the ground. It would be so common in fact it would be an every day observation that you would not request us playing with some candles, as it would be accepted.

I am also not making things up, all the measurements we did using these laser sources was to calibrate a Dark Matter experiment located 2km underground. I can honestly say that nothing happens to the colour or brightness of my cap lamp when i check it on surface (battery powered) and then go underground and walk through the drift. Things don't magically appear bluer or redder by human observation, nor do they gain or loose brightness.

Yet you are asking us to prove an experiment that you have very contradictory reasons for working compared to what we humans observe on a day to day basis. Furthermore, I do not have in my possession a good enough spectroscope or monochromator for what you wish to check but, once again, a spectroscope or monochromator would be meaningless if the effects are as enormous as you suggest