**Ask a monkey a physics question thread**

[OngBonga]

Still sounds to me like doing the exact same experiment will yield two different results based on whether or not certain parts of that experiment are being observed.

observed = measured

The act of measuring changes the initial conditions. Of course there will yield two different results based on whether or not it was observed. That's not spooky, it's totally intuitive. How do you "meausre" the velocity and location of a particle? Or, more to the point, how do you do this accurately without altering its trajectory and thus changing the conditions? Hint - you can't, see "uncertainty prinicple".

The double slit experiment can be explained by pilot wave theory. I'm not sure what to make of it all, but the basic gist is every particle has an associated wave, and the wave essentially carves out a geomoetric path for the particle to follow. The trajectory of the particle is determined by its initial conditions, at least until we try to measure it, thus changing its trajectory.

[BananaStand]

The act of measuring changes the initial conditions. Of course there will yield two different results based on whether or not it was observed. That's not spooky, it's totally intuitive.

So I can change the temperature outside by walking outdoors with a thermometer? Sorry, I'm not buying it.

The fact that I can change the behavior of matter in a way that defies the rules of physics, merely by exercising my own consciousness, pretty much proves that I am God.

Or at least, a god

[MadMojoMonkey]

So I can change the temperature outside by walking outdoors with a thermometer?

Theoretically, yes... ish.
Your presence is definitely emitting ~75 Watts of heat when you're inactive. It can be as high as ~150 Watts under intense physical exertion, like any time your breathing is elevated for a sustained period.
This is going to trump the small amount of heat being absorbed or emitted by the thermometer as it comes into thermodynamic equilibrium.

Being able to measure and prove the heat a body emits in a well insulated room of any size is standard. In laboratories where temperature control is essential, there is generally a line of 100 W lamps in the room and whenever a researcher enters the lab, they turn off a light, and turn it back on when they leave. This helps maintain the heat being generated in the lab.

Proving this happens in the atmosphere with a thermometer is going to be impossible.

Conservation of Energy still holds that if you're emitting heat into the atmosphere, then the atmosphere is getting warmer. Whether or not you're inside is probably of minimal relevance. The air in your house is cycled with outside air more often than you may think, but it varies widely. It's just that the atmosphere is really big [citation needed] and the cumulative effect your body heat has on global climate is negligible.

Sorry, I'm not buying it.

There goes my retirement!

The fact that I can change the behavior of matter in a way that defies is explained by the rules of physics, merely by exercising my own consciousness, pretty much proves that I am God.

Or at least, a god

FYP, oh mighty god-brother.

[MadMojoMonkey]

observed = measured

In this context, yes.

The act of measuring changes the initial conditions. Of course there will yield two different results based on whether or not it was observed. That's not spooky, it's totally intuitive. How do you "meausre" the velocity and location of a particle? Or, more to the point, how do you do this accurately without altering its trajectory and thus changing the conditions? Hint - you can't, see "uncertainty prinicple".

This is measurement uncertainty and it is a separate problem than quantum uncertainty laid out in the uncertainty principle.

Measurement uncertainty is a common problem. Consider measuring your car's tire's pressure. By attaching the pressure gauge to the tire, you obtain a reading by releasing some of the pressure into the tire pressure gauge. You cannot measure the pressure with that gauge without altering the pressure you're trying to measure.

This applies to quantum particles, too, but it is NOT the uncertainty principle.

The uncertainty principle says that, even with "perfect" measurement devices, you still cannot simultaneously measure the position and momentum of something to arbitrarily high precision. Those properties DON'T SIMULTANEOUSLY EXIST IN THE UNIVERSE for any particle... because particles are waves, and waves have this property.

The double slit experiment can be explained by pilot wave theory. I'm not sure what to make of it all, but the basic gist is every particle has an associated wave, and the wave essentially carves out a geomoetric path for the particle to follow. The trajectory of the particle is determined by its initial conditions, at least until we try to measure it, thus changing its trajectory.

That pilot wave is the imaginary portion to the solutions of Schroedinger's Wave Equation. Particle wave functions are complex-valued. To determine probabilities of observing certain properties of a particle, you square the wave function and integrate over some domain. The squaring eliminates all negative and complex values from the result, making them neatly measurable predictions.

There is no known way to measure a complex-valued wave, and the pilot wave theory is predicated on these imaginary solutions directing the particles' apparently random motions in deterministic ways. It's a comfortable view, but not falsifiable by any known means, so not, strictly speaking, science.