Position of elementary particles

In summary, your teacher is talking about the uncertainty principle. This principle says that for a subatomic particle, the location and momentum uncertainties are always greater than a constant. This means that we can't predict the position of a particle with certainty.
  • #1
Helicobacter
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My teacher told me that elementary particles don't have position. Well, I don't understand this; it's like an oxymoron to me. Anyone with a easy-to-understand explanation?
 
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  • #2
What your teacher is talking about is something called the uncertainy principle. What that says is that for a subatomic particle (uncertainy of location X uncertainy of momentum) >= constant. In other words, you can't know the exact location or momentum of a particle. And as the uncertainy of momentum goes down, the uncertainy of location goes up and visa versa.

This means that we can't peg a subatomic particle at exactly one location. There is a limit of uncertainy that can't be passed. Sure they have position, but the position is smeared.
 
  • #3
Actually, we need to be careful with this. Your teacher is describing the uncertainty principle, which is often misunderstood. The reason why I say this is because many elementary particles, such as an electron, CAN have a definite position. When an electron hits a screen, it makes a DOT, and you have already determined that the electron had that position.

The uncertainty principle indicates our ability to PREDICT the relevant measurement under identical conditions. It doesn't say that a particle doesn't have a "position". It does. It is just how well we can tell the position measurement would turn out if we happen to know its momentum before hand.

Zz.
 
  • #4
Helicobacter said:
My teacher told me that elementary particles don't have position. Well, I don't understand this

Your teacher told you that the particles in QM (every particle, not only elementary) are fields and therefore in general have infinitely many positions. As interested_learner and ZapperZ explain to you, in the specific physical situation it may be just a single point in space(position). Today experimenters may show to you the detailed picture of the single electron/photon with any precision you will require.

Dany.
 
Last edited:

1. What are elementary particles?

Elementary particles are the smallest known units of matter that cannot be broken down into smaller pieces. They are the building blocks of all matter in the universe.

2. What is the position of elementary particles?

The position of elementary particles refers to their location in space at a given time. This position can be described using coordinates in a specific reference frame.

3. How is the position of elementary particles measured?

The position of elementary particles is measured using various experimental techniques such as particle accelerators, detectors, and imaging technologies. These techniques allow scientists to observe and track the movement of particles in space.

4. Can the position of elementary particles change?

Yes, the position of elementary particles can change over time due to interactions with other particles or forces. The uncertainty principle in quantum mechanics states that the precise position and momentum of a particle cannot be known simultaneously, so the position of elementary particles can only be described probabilistically.

5. Why is the position of elementary particles important in physics?

The position of elementary particles is important because it provides crucial information about the behavior and interactions of particles, which can help us understand the fundamental laws of physics. It also plays a crucial role in many technological applications, such as in particle accelerators and medical imaging devices.

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