Quantum Physics tells us that ..., is this true?

Question

Quantum Physics tells us that the very act of observing something changes it, is this true or pop science nonsense?

Answer 1

Your statement is true, however I have to disagree with some of the answers posted before. Some of them mistakenly claim that it is due to the Heisenberg's Uncertainty Principle when it is not. The uncertainty principle is a consequence of the wave-like nature of particles, and has nothing to do with a measurement. Actually, the effect mentioned in your questions was discovered during experiments, while the uncertainty principle comes out of the mathematical framework of quantum mechanics.
The answer has more to do with the collapse of the wave function, which is not explained by any theory and has to be included by hand using brute force.
In any case, quantum mechanics is complicated because it forces you to believe in things that seem counterintuitive, and you do not need to get into it to find out the answer to your question.

Answer 2

With quantum physics we're referring to sub atomic particles. It is true that if we observe a particle there is a change that occurs. It's called the heisenberg uncertainty principle.

Basically it states that if we observe a particle's position in a moment in time we lose all information about it's original velocity. And if we observe it's velocity we will lose all information about where it happens to be at a specific moment in time.

We see objects by energy striking the object and bouncing back to us, and being interpreted by our brain or a sensor or a computer as to what we're seeing. This can be from light, or even sound, like with sonar or simply viewing an object in a lit environment.

With observing a particle like an electron we have to shoot an electron at it to observe it at a specific point in time, but in doing so it's like a pool game.

You have a pool ball moving around the table and you can only see it if you hit it with the cueball. You shoot the cueball and hit it, it's deflected off of it's original path and while you can see where it was when you struck it, you don't know where it was going toward.

Similarly when you know where it's going, you will not be able to observe it's position in a specific moment in time.

Quantum physics has many strange and bizarre rules and phenonema that occur, but they have actually been demonstrated to be true. Quantum tunneling and "spooky action at a distance" are another couple of things that have been proven and still seem very wierd...

Answer 3

What you are probably thinking of is called the Copenhagen Interpretation of quantum mechanics. In the C.I., objects don't have well defined properties until after you make a measurement. The act of measurement forces the particle to "take a stand" and "pick" its properties. Many people have had difficulty believing this interpretation since its based in a more subjective kind of philosophy. (in subjective philosophy, the mind and ideas are more "real"...in objective philosophy, the external world exists as we observe it) As for the Heisenberg Uncertainty Principle, what it says is that we can't know both the position and momentum of a particle with exact precision. You can still measure and know both the position and momentum, but the measurement process necessarily produces a small amount of uncertainty in the values you obtain. The more accurately you know one value, the less accurately you know the other.

Answer 4

Quantum physics is the most accurate and most supported (by experimental evidence) of the modern theories of science. It is not "pop science nonsense". Quantum mechanics deals with very small entities such as submicroscopic particles like the elementary particles of matter (The electron, proton, neutron etc,). These are altered in either position or momentum by the very act of observing them. Also it is true that these quantum particles exist as an infinite number of "smeared out"superpositions which collapse into one entity with a probabilistic position and momentum on observation..

The havoc wreaked on common sense by quantum mechanics leads many scientists to regard its accurate predictions as spooky at best. For a mathematical mind it is real; to a mind needing concrete things to believe in it is dumbfounding. A couple references for the mathematically minded are: Jeremy Bernstein et. al.;"Modern Physics": Prentice Hall, Upper Saddle River NJ,07458, 2000 and Roland Omne's; "Understanding Quantum Mechanics"; Princeton Univ Press, Princeton NJ 08540, 1999

(Grammatically edited after 4 hours.)

Answer 5

You've got some good answers here, but I'll add that the Uncertainty Principle applies to all objects, not just microscopic ones. The effect is unbelievably miniscule for macroscopic objects, and yet there are physics experiments in which it is important. The LIGO experiment must account for the Heisenberg uncertainty in the positions of two 20 kilogram bowling balls.

Answer 6

Its true on the subatomic level. To measure the position or velocity of a particle, you interact with it, thus changing it in some way (remember to see something means that light has to bounce off of it).

Keep in mind that quantum mechanics only applies to the subatomic level so that many of the observed facts may seem unbelievable if you base it on what you observe in the macroscopic (every day) world.

Answer 7

It's known as Heisenbergs uncertainty principle - and yes, it's true.

On the molecular level, when you want to look at something, you need to use powerful machines, such as an electron microscope. In using this, you bombard the particle with electrons, which thus effect it.

The principle actually states that you can never know both the position and the velocity at the same time. You can only know one or the other.

Remember though this is at the atomic level.

Answer 8

Yes it is true. It is called ‘Heisenberg’s Uncertainty Principle’.
Most people would know that we use light to see objects. This light, when it falls on very small objects - like an electron - gives it more energy, sets it into vibration and thus changes its location.
But if it falls on big objects like you and I the energy we receive from it is so small that we are delocalized by about 1/exp (30) meters, which compared to the motion that we see in real life, is practically non-existent.
So it may be of some use to Einstein, but for laymen like us it is what it is –

Nonsense.

Answer 9

It's not pop science, it is true, the mathematics (much too complex to try to explain here) tells us so. But no-one really understands *why* it is so. Many theories have been put forward, but none are universally agreed.

If you are up to some advanced mathematics, there are many sources available on the net - you could try looking up Bell's Theorem, for example, or Schoedinger's cat - but none are easy to understand, unless you are at undergrad level or above. If you *are* at that level, they are clear, and irrefutable.
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Answer 10

on the subatomic level you can never know both the position and momentum of the body at the same time(consequently you will not be able to know the velocity and position at the same time).
hence the answer to your question is yes,but on a very small object,such as an atom or sub-atomic particles.