The Binding Curve

Plate 46 speaks for itself: “Climb to the peak.”

The Physics

The binding energy per nucleon rises from light nuclei to a peak near iron and nickel, then slowly falls. Fusing light nuclei or splitting heavy ones moves toward the peak and releases energy.

B = (Z·m(¹H) + N·m_n − M) c²

• B: total binding energy, J (quoted in MeV)
• Z: proton number, dimensionless
• N: neutron number, dimensionless
• m(¹H): hydrogen-1 atomic mass, kg
• m_n: neutron mass, kg
• M: atomic mass of the nuclide, kg
• c: speed of light, m s⁻¹

⁶²Ni highest: 8.7945 MeV per nucleon; ⁵⁶Fe 8.7903. Light fuse, heavy split: energy out.

Sources

• M. Wang et al., AME2020, Chinese Phys. C 45, 030003 (2021).
• M. P. Fewell, Am. J. Phys. 63, 653 (1995).

On the poster

Plate 046, “The Binding Curve”: the pixel-art plate with its slogan “Climb to the peak.”, the key equation and the facts panel shown above. Pixelated Physics. Physics. Personified.