A nucleus has: Radius R=R0A1∕3, where R0≈1.2×10−15m Each nucleon (proton or neutron) has a mass mn≈1.67×10−27kg Step 2: Estimate the number of nucleons per unit volume For nuclear matter, the volume per nucleon is roughly the volume of a sphere of radius R0 : Vper nucleon ≈
4
3
πR03 Vper nucleon ≈
4
3
π(1.2×10−15)3≈7.2×10−45m3 Hence, number density of nucleons: n=
1
Vper nucleon
≈
1
7.2×10−45
≈1.4×1044m−3 Step 3: Compute the mass density ρ=n×mn=(1.4×1044)(1.67×10−27)≈2.3×1017kgm−3 Density of nuclear matter ∼1017kgm−3
