Calculating the Density of a Neutron

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Discussion Overview

The discussion revolves around the calculation of the density of a neutron, focusing on the method used to derive this density from the neutron's mass and volume. Participants explore the implications of modeling the neutron as a sphere and the relevance of its radius in the calculation.

Discussion Character

  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant calculates the density of a neutron to be approximately 3.19887549*10^57 kg/m^3 using the formula Density = mass/volume, with the neutron modeled as a sphere.
  • Another participant confirms the method is correct but questions the source of the radius used in the calculation.
  • A different participant references Heisenberg's uncertainty principle, suggesting that knowing one variable of a subatomic particle introduces uncertainty in another, which may impact the relevance of the density calculation.
  • Some participants argue that the neutron's radius is unknown and that treating it as a point particle renders the density calculation meaningless, emphasizing the importance of its mass instead.
  • There is a correction regarding the mass of the neutron, with a participant asserting that the value used is incorrect and suggesting that the neutron has a measured radius, though its boundary is not sharp.
  • Another participant points out that the radius of 10^-10 m is more representative of an atom rather than a neutron, suggesting that a more appropriate scale for a neutron's radius is around 10^-15 m.

Areas of Agreement / Disagreement

Participants express disagreement regarding the neutron's radius and the validity of using density as a meaningful property. There is no consensus on the correct radius or the relevance of density in the context of subatomic particles.

Contextual Notes

The discussion highlights uncertainties regarding the neutron's radius and the implications of treating it as a point particle. The calculations depend on specific assumptions about the neutron's properties, which are not universally agreed upon.

FeDeX_LaTeX
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Hi, I did some calculations and I worked out the density of 1 neutron to be about 3.19887549*10^57 kg/m^3. However, I want to know if the method I used is correct.

Density = mass/volume, correct?

If this is true, then

Density = [mass of neutron]/[volume of neutron]

I found the volume of a neutron by modelling it as a sphere, with volume (4/3)pi*r^3. The calculation I ended up doing was;

(1.67492729*(10^27))/(4/3 * pi*((10^-10)/2)^3) = 3.19887549*10^57 kg/m^3

Where the 1.67492729 is the mass of a neutron (source: wikipedia).

Is my working correct?

Cheers
 
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The method is correct, but where did you get r?
 
mathman said:
The method is correct, but where did you get r?

It really doesn't matter, since Warner Heisenberg already showed us that when the quantity of one non-commuting variable is known in the subatomic particle, the other variable of that particle becomes uncertain (Heisenberg's uncertainty principle).
 
I personally think the neutron's radius is unknown yet
And since we always regard neutron as a point,its density is useless
We need only its mass
 
netheril96 said:
I personally think the neutron's radius is unknown yet
And since we always regard neutron as a point,its density is useless
We need only its mass

Agreed. I'd also like to add that we need know also the neutron's energy (in electron-volts, of course), as well as its spin.
 
FeDeX_LaTeX said:
1.67492729*(10^27)

1.67492729 x 10^27 is most certainly not the mass of the neutron. Check again,.

netheril96 said:
And since we always regard neutron as a point

No we don't. The neutron has a measured radius. Of course, it's boundary is not sharp, but you could say that about many things that have a published radius: a gold atom, the planet Jupiter, the asteroid belt.
 
10^-10 is more like the radius of an atom (where the electron likes to hang out). It's not the radius of the Neutron...but I suppose you could use that as an upper bound. (Nuclei are more on the order of 10^-15m in radius)
 

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