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    Nucleation Calculator

    Copper undercooled by 200 K forms stable nuclei above a critical radius of 1.27854 nm, a cluster of several hundred atoms.

    Solid–liquid copper about 0.177 J/m².

    Copper 1.88 × 10⁹ J/m³.

    Critical radius r* =

    1.27854255319149 nm

    Full answer, then cut to fewer decimals (not rounded):

    • 1.27854255319149 nm
    • 1.2785425531914 nm
    • 1.278542553191 nm
    • 1.27854255319 nm
    • 1.2785425531 nm
    • 1.278542553 nm
    • 1.27854255 nm
    • 1.2785425 nm
    • 1.278542 nm
    • 1.27854 nm
    • 1.2785 nm
    • 1.278 nm
    • 1.27 nm
    • 1.2 nm
    Driving force ΔG_v = ΔH_f ΔT/T_m
    276877761.4 J/m³
    Homogeneous barrier ΔG*
    1.21197106 × 10⁻¹⁸ J
    Barrier in eV
    7.56452837 eV
    Heterogeneous factor S(θ) = (2 + cos θ)(1 − cos θ)²/4
    0.15625
    Heterogeneous barrier ΔG*S(θ)
    1.893704782 × 10⁻¹⁹ J
    Step-by-step solution
    1. ΔG_v = ΔH_f ΔT ÷ T_m = 1880000000 × 200 ÷ 1358 = 276877761.4 J/m³
    2. r* = 2γ ÷ ΔG_v = 1.278542553 nm
    3. ΔG* = 16πγ³ ÷ (3ΔG_v²) = (1.21197106 × 10⁻¹⁸) J

    Nucleation Formula

    r* = 2γ/ΔG_v, ΔG* = 16πγ³/(3ΔG_v²)

    ΔG_v = ΔH_f ΔT / T_m; heterogeneous S(θ) = (2 + cos θ)(1 − cos θ)²/4

    Worked Example

    Copper solidifying with 200 K of undercooling:

    1. ΔG_v = ΔH_f ΔT ÷ T_m = 1880000000 × 200 ÷ 1358 = 276877761.4 J/m³
    2. r* = 2γ ÷ ΔG_v = 1.278542553 nm
    3. ΔG* = 16πγ³ ÷ (3ΔG_v²) = (1.21197106 × 10⁻¹⁸) J

    Homogeneous barrier ΔG*: 1.21197106 × 10⁻¹⁸ J · Barrier in eV: 7.56452837 eV · Heterogeneous factor S(θ) = (2 + cos θ)(1 − cos θ)²/4: 0.15625 · Heterogeneous barrier ΔG*S(θ): 1.893704782 × 10⁻¹⁹ J

    GATE tip

    r* ∝ 1/ΔT and ΔG* ∝ 1/ΔT². Doubling the undercooling halves the critical radius and quarters the barrier, so nucleation rates rise steeply.

    More Physical Metallurgy Calculators

    All GATE Metallurgical Engineering calculators →

    Frequently asked questions

    Why is undercooling needed?

    At the melting point the volume driving force is zero, so the surface energy cost makes every nucleus unstable; ΔG_v grows with ΔT, shrinking r* and ΔG*.

    Why does heterogeneous nucleation dominate?

    A wetting surface (mould wall, inoculant) reduces the barrier by S(θ); at θ = 60° the barrier is only 16 % of the homogeneous value.

    Sources

    Last reviewed: . Factors are stored exactly and computed with 50-digit decimal arithmetic. See how we verify conversion factors.

    Cite this page

    APA

    Scientific Converters. (2026, October 15). Nucleation Calculator. Retrieved October 25, 2026, from https://scientificconverters.com/calculators/nucleation-calculator/

    IEEE

    Scientific Converters, "Nucleation Calculator," scientificconverters.com. Accessed: Oct. 25, 2026. [Online]. Available: https://scientificconverters.com/calculators/nucleation-calculator/

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