Determining Electron's Momentum and Position Simultaneously

  • Context: High School 
  • Thread starter Thread starter lisathomas
  • Start date Start date
  • Tags Tags
    Electron
Click For Summary

Discussion Overview

The discussion revolves around the challenge of determining an electron's momentum and position simultaneously, exploring concepts from quantum mechanics and analogies used in teaching. The scope includes conceptual understanding and the application of quantum principles in educational contexts.

Discussion Character

  • Conceptual clarification, Exploratory

Main Points Raised

  • One participant shares an analogy using a ceiling fan to explain the uncertainty principle, suggesting that while one can observe speed or position, one cannot measure both simultaneously for electrons.
  • Another participant counters that electrons do not follow classical trajectories and that quantum mechanics requires a different understanding based on states and state vectors, indicating that the ceiling fan analogy is not applicable.
  • A later reply expresses appreciation for the explanation provided, indicating a positive reception to the clarification offered.
  • Another participant reflects on the value of curiosity in teaching, suggesting that such inquiries are beneficial in educational settings.

Areas of Agreement / Disagreement

Participants do not reach a consensus, as there is a disagreement regarding the applicability of classical analogies to quantum mechanics. Some participants appreciate the initial analogy while others challenge its validity.

Contextual Notes

The discussion highlights the limitations of classical analogies in explaining quantum phenomena, as well as the need for a deeper understanding of quantum mechanics that diverges from classical intuitions.

Who May Find This Useful

This discussion may be useful for educators seeking to understand the complexities of teaching quantum mechanics concepts and for those interested in the philosophical implications of measurement in quantum physics.

lisathomas
Messages
3
Reaction score
2
TL;DR
Is it possible to retrospectively determine the position and speed of an electron at the same moment?
Hi. I am a high school science teacher (A&P, Chem, and Environ Bio & Eco) so my understanding is limited on subatomic particles...please forgive me if this is a really stupid idea.

I teach my chem students about electrons, orbitals, electrons' "address" using the four quantum numbers, 1s2 -1/2 spin. I use the example of an airplane's propellers or a fan's blades to explain that we can know how fast they are traveling or their exact position but not both at the same time. I was watching my fan in my bedroom this morning turning around and around and I would pick a blade and watch it then allow it to blur in with the rest as I watched all the blades turn at a slow speed. Then, I began to blink my eyes rapidly which allowed me to take "moment pictures" which allowed me to see the placement of each blade and the speed of my eyes opening and closing with the change in position of the blades allowed me to "measure" the speed. Is there some way we could do that in a lab with electrons?
 
Last edited by a moderator:
Physics news on Phys.org
An atom is a bound energy state of its constituent particles. The electrons do not have classical trajectories, in terms of position as a function of time; or, momentum as a function of time.

QM involves an entirely different description of nature, based on states and state vectors, as opposed to classical trajectories. The ceiling fan analogy doesn't apply, I'm sorry to say.
 
Reply
  • Like
Likes   Reactions: Delta Prime and lisathomas
Wow! Thank you for the clear explanation.
 
Reply
  • Like
Likes   Reactions: berkeman and weirdoguy
Wish when I was in school I had a teacher curious enough to post this
 
Reply
  • Like
Likes   Reactions: ersmith and lisathomas
Oh, thank you! That is so kind.
 

Similar threads

High School I have question regarding quantum physics (localizing an electron)
  • · Replies 6 ·
Replies
6
Views
2K
High School Life of free electrons in space
  • · Replies 2 ·
Replies
2
Views
4K
Undergrad Expectation value of the momentum for an electron in a box
  • · Replies 3 ·
Replies
3
Views
1K
Undergrad About the position of electrons (uncertainty)
  • · Replies 6 ·
Replies
6
Views
4K
High School Are electrons in atoms always in eigenstates?
  • · Replies 6 ·
Replies
6
Views
2K
Graduate Are Quantum Mechanics and a rotating fan comparable?
  • · Replies 11 ·
Replies
11
Views
2K
High School Can the Motion of an Electron in Quantum Mechanics Be Reversed?
  • · Replies 29 ·
Replies
29
Views
3K
Undergrad Quantum Mechanics as a Probabilistic forecast of reality
  • · Replies 21 ·
Replies
21
Views
2K
High School Understanding Electron Spins: A High Schooler's Guide”
  • · Replies 11 ·
Replies
11
Views
1K
High School How does the electric field of an electron compare to its probability wave?
  • · Replies 5 ·
Replies
5
Views
2K