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Maslova
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Once I have read that we can’t know a actual position of a particle because to see the particle we need to send photons and when we send photons it colides with the particle and change it’s position. Is this true?
Maslova said:I have read
PeterDonis said:Can you give a specific reference?
Maslova said:it’s in Portuguese
This is the book. Just in PortuguesePeterDonis said:What is the title of the book, or article, or whatever it is? Is there an English translation?
Maslova said:This is the book.
Scientific divulgationPeterDonis said:What kind of book is it? Is it a textbook? A popular science book?
Maslova said:Scientific divulgation
Science popularization, science communicationPeterDonis said:I don't know what "divulgation" means.
Maslova said:Science popularization, science communication
Thanks for the explanation!PeterDonis said:Ok, that was the impression I got from looking the book up on Amazon. Popularizations are generally not good sources for learning the actual science.
In this particular case, the book appears to be describing the uncertainty principle in quantum mechanics. However, the description you give, which I assume is based on what the book says, is not quite correct. The uncertainty principle does not place any limit on how accurately you can measure a particle's position. What it does place a limit on is this: the more accurately you measure the particle's position, the greater the uncertainty in its momentum will be after the measurement.
For example, if you are measuring the position with a photon, the uncertainty in the position measurement is approximately the wavelength of the photon, so to make the position measurement very accurate you will have to use a photon of very short wavelength. But such a photon will have a very large momentum, so when it collides with the particle it will change the particle's momentum by a very large, unknown amount.
Why unknown?PeterDonis said:But such a photon will have a very large momentum, so when it collides with the particle it will change the particle's momentum by a very large, unknown amount.
Demystifier said:Why unknown?
PeterDonis said:Ok, that was the impression I got from looking the book up on Amazon. Popularizations are generally not good sources for learning the actual science.
In this particular case, the book appears to be describing the uncertainty principle in quantum mechanics. However, the description you give, which I assume is based on what the book says, is not quite correct. The uncertainty principle does not place any limit on how accurately you can measure a particle's position. What it does place a limit on is this: the more accurately you measure the particle's position, the greater the uncertainty in its momentum will be after the measurement.
For example, if you are measuring the position with a photon, the uncertainty in the position measurement is approximately the wavelength of the photon, so to make the position measurement very accurate you will have to use a photon of very short wavelength. But such a photon will have a very large momentum, so when it collides with the particle it will change the particle's momentum by a very large, unknown amount.
cosmik debris said:I thought that the uncertainty principle wasn't about measurement but about preparation
The position of a particle refers to its location in space at a given time. It is typically described using a coordinate system, such as Cartesian coordinates, where the particle's position is represented by a set of numerical values.
The position of a particle can be measured using various techniques, depending on the type of particle and the precision required. Some common methods include using rulers or measuring tapes for macroscopic particles, and more advanced techniques such as electron microscopy for microscopic particles.
The uncertainty principle, also known as Heisenberg's uncertainty principle, states that it is impossible to know the exact position and momentum of a particle simultaneously. This means that the more precisely we measure the position of a particle, the less precisely we can know its momentum, and vice versa.
Photons are particles of light that have both wave-like and particle-like properties. They are the fundamental units of electromagnetic radiation and do not have a well-defined position. Instead, their position can only be described in terms of a probability distribution, as they can exist in multiple places at the same time.
The position of a particle can have a significant impact on its behavior, as it determines how the particle will interact with its surroundings. For example, the position of an electron in an atom determines its energy level and can affect its ability to participate in chemical reactions. In the case of photons, their position can determine the direction and intensity of light as they travel through space.