{
  "claim_id": "thompson1917-ch02-06",
  "claim_iri": "https://w3id.org/delphi/resource/claim/thompson1917-ch02-06",
  "related_claims": [
    "thompson1917-ch02-07",
    "thompson1917-ch02-10"
  ],
  "project": "thompson-growth-form",
  "thread": "physics",
  "status": "complete",
  "preregistered_at": "2026-10-31T18:21:00Z",
  "hypothesis": "If Thompson's similitude argument holds, an animal in steady lift-supported flight or glide must move at least at v_min = sqrt(2 W / (rho S C_Lmax)), and across animals of roughly similar design the characteristic airspeed scales with wing loading W/S to the power 1/2 (equivalently, under isometry, with linear size to the power 1/2 and with body mass to the power 1/6).",
  "interpretations": [
    {
      "id": "A-speed-law",
      "reading": "Across lift-supported fliers and gliders, characteristic airspeed v scales with wing loading Q = W/S as v ~ Q^0.5 (ch02-06 first half, ch02-10).",
      "provable": false,
      "why": "The exponent follows from the lift equation only if C_L and air density are the same across taxa; whether real animals satisfy that is empirical."
    },
    {
      "id": "B-fish-inside-envelope",
      "reading": "A flying fish in a steady glide moves at or above its own minimum lift-supported speed computed from its measured wing loading and measured maximum lift coefficient.",
      "provable": false,
      "why": "A consistency check of the fish against the model; needs measured W, S, C_Lmax and airspeed."
    },
    {
      "id": "C-power-envelope",
      "reading": "Power required for level flight P_req = W v_min / (L/D)_max exceeds muscle power available P_avail = m_muscle * p_specific for the flying fish at its size (ch02-07 reading: beyond some size muscle-powered flight is impossible).",
      "provable": false,
      "why": "Needs a sourced muscle mass fraction and a sourced mass-specific muscle power; if either is unsourced the verdict is cannot-tell."
    },
    {
      "id": "D-exponents",
      "reading": "Given W ~ L^3, S ~ L^2, constant C_L and rho, then v_min ~ L^0.5 and P_req ~ L^3.5 while P_avail ~ L^3.",
      "provable": true,
      "why": "A mathematical consequence of the stated definitions; goes to the Lean thread via physics/FORMAL-STATEMENTS.md, not tested on data here."
    }
  ],
  "pass_criterion": "Pre-registered. Interpretation A: pool every taxon in physics/glide-data.csv and physics/comparison-data.csv that has a measured body weight W (N), a measured lifting area S (m^2) and a measured steady airspeed v (m/s) from a fetched source (field, video or wind tunnel; simulations excluded; one row per species, the median if several). Ordinary least squares of log10 v on log10 (W/S). SUPPORTS if n >= 5 taxa spanning at least one decade of W/S AND the 95% CI of the slope contains 0.5 AND excludes 0. Interpretation B: INSIDE the envelope if the flying fish's measured airspeed range overlaps [v_min, 3 v_min] with v_min = sqrt(2 W / (rho S C_Lmax)), rho = 1.225 kg m^-3, C_Lmax the measured maximum lift coefficient from a wind-tunnel source, W and S from the same species or genus. Interpretation C: INSIDE if P_avail >= P_req using only sourced values.",
  "fail_criterion": "Pre-registered. Interpretation A: REFUTES if n >= 5 AND the 95% CI of the slope excludes 0.5. INCONCLUSIVE (underpowered) if n < 5, or the CI width exceeds 1.0, or the W/S range spans less than one decade. Interpretation B: OUTSIDE if the entire measured airspeed range lies below v_min (the glide could not be lift-supported) or above 3 v_min; CANNOT TELL if any of W, S, C_Lmax or airspeed lacks a measured value with a fetched source. Interpretation C: OUTSIDE if P_avail < P_req with sourced inputs; CANNOT TELL otherwise. MIXED if interpretations disagree in sign.",
  "planned_datasets": [
    "physics/glide-data.csv (built from fetched sources listed in physics/SEARCHES.md)",
    "physics/comparison-data.csv (bats, flying squirrels, colugos, flies; same provenance rules)"
  ],
  "holdout_rule": "Class Aves is the frozen holdout (holdout/exam.json) and this claim is listed there as a bird-only claim. No bird row is read, fitted or plotted. The kickoff's comparison set named birds; they are excluded here as a deviation and the hub has been asked to confirm.",
  "interpretation": "Thompson's 'linear dimensions' l is replaced by the directly measurable wing loading W/S, which is what his own derivation (momentum balance over the wing area) actually uses; l^0.5 follows only under isometry (W ~ l^3, S ~ l^2). 'Speed' is the steady glide or cruising airspeed, not the launch speed. 'Work of flight' is the mechanical power required for level flight at v_min. Air density is taken as sea-level standard. The flying fish is a glider; interpretation C asks the hypothetical question whether its muscles could power level flight, which is what #43 and the Darwin claim need.",
  "already_seen_before_preregistration": [
    "Makiguchi et al. 2013 (10.3354/ab00494) full text: fork length 25.7-34.0 cm, body mass 178-263 g for 13 Cypselurus heterurus doederleini; estimated leap speed 3.87-5.15 m/s; pitch 20.0 +- 3.3 deg.",
    "Abstracts only: Davenport 1994 (approach ~10 m/s, taxiing up to 50 beats/s), Deng et al. 2019 CFD (C_Lmax 1.05, L/D max 4.7, predicted 45.4 m and 13.2 m; simulation, not used as data), Park and Choi 2010 (L/D max near 0 deg, C_L largest at 30-35 deg; glide performance comparable to some bird wings), Fish 1990 (fin area and span increase with mass).",
    "No wing loading, lifting area or C_Lmax value had been read for any taxon when this file was written; no comparison-taxon value had been read."
  ],
  "datasets": [
    {
      "id": "physics-glide-data-2026-10-31",
      "name": "physics/glide-data.csv",
      "landing_url": "physics/glide-data.csv",
      "doi": null,
      "version": "2026-10-31T18:36:55Z",
      "license": "CC BY 4.0 for the compilation; each value belongs to its source",
      "files": [],
      "role": "flying-fish morphometry and quoted field speeds; sources in physics/sources.json"
    },
    {
      "id": "physics-comparison-data-2026-10-31",
      "name": "physics/comparison-data.csv",
      "landing_url": "physics/comparison-data.csv",
      "doi": null,
      "version": "2026-10-31T18:36:55Z",
      "license": "CC BY 4.0 for the compilation; each value belongs to its source",
      "files": [],
      "role": "non-bird comparison lineages"
    }
  ],
  "method": "analysis.py reads the two CSVs. B: v_min = sqrt(2W/(rho S C_Lmax)) for the Park and Choi L3 specimen (W from its mass, S = A1+A2+A3, C_Lmax 0.78) compared with the second-hand field airspeed range. A: OLS of log10 v on log10 (W/S), gliders and powered fliers separately, with the pre-registered n, decade and CI rules. C: P_req = W v_min/(L/D)_max; no sourced P_avail. Every number is in physics/results.json.",
  "measured": {
    "value": 9.854014478123766,
    "unit": "m/s, minimum lift-supported speed of the Cypselurus hiraii L3 specimen",
    "n": "one specimen for W, S, C_Lmax; family-level airspeed range",
    "uncertainty": "none computable from one specimen; the second specimen (Kawachi, 0.226 kg) gives 14.4 m/s with the same C_Lmax",
    "extra": {
      "airspeed_range_m_s": [
        10.0,
        20.0
      ],
      "wing_loading_L3_N_m2": 46.39029003783103,
      "P_req_W": 1.3272478081976313,
      "A_gliders": {
        "n": 2,
        "slope": null,
        "slope_ci95": null,
        "decades_of_WS": 0.10442492385208069,
        "verdict": "inconclusive",
        "why": "n = 2 < 5; W/S spans 0.10 decades < 1"
      },
      "A_powered": {
        "n": 6,
        "slope": 0.41937638662824034,
        "slope_ci95": [
          0.11155092765614155,
          0.7272018456003391
        ],
        "decades_of_WS": 0.9310983931969457,
        "verdict": "inconclusive",
        "why": "W/S spans 0.93 decades < 1"
      }
    }
  },
  "verdict": "inconclusive",
  "confidence": 0.5,
  "caveats": [
    "Thompson's muscle-power-as-l^3 premise is itself an assumption (constant mass-specific power); modern work treats it as size-dependent. Recorded in physics/FORMAL-STATEMENTS.md as an assumption, not tested here.",
    "W, S and C_Lmax are from 0.04-0.06 kg stuffed specimens of one species; the airspeed range is a second-hand field figure for larger flying fish of several genera. The pre-registration allowed same species or genus; the field figure is at family level, so this verdict rests on an assumption the pre-registration did not foresee and is reported with that weakness.",
    "Interpretation A powered set: wing loadings for the three hoverflies come from a compilation whose own mass and area columns disagree with its wing-loading column by a factor of 5 to 8; bat speeds are wind-tunnel test speeds, not cruising speeds.",
    "Interpretation A glider set has two taxa with both W/S and speed (flying fish, northern flying squirrel); the colugo has a speed but no sourced wing loading.",
    "Class Aves is the frozen holdout: no bird enters any fit, table or figure."
  ],
  "agent": {
    "kind": "claude-code-session",
    "model": "claude-fable-5-1",
    "run": "scienceclaw-58 physics thread",
    "date": "2026-10-31"
  },
  "amendments": [
    {
      "at": "2026-10-31T18:26:00Z",
      "before_any_fit": true,
      "requested_by": "hub (Main) after reading the pre-registration",
      "changes": [
        "Exocoetidae is explicitly in the interpretation-A set: its rows come from physics/glide-data.csv; the comparison lineages come from physics/comparison-data.csv.",
        "Gliders (Exocoetidae, Pteromyini, Cynocephalidae) and powered fliers (Chiroptera, Diptera) are two physical regimes. The interpretation-A regression is run separately for each group, and each group needs n >= 5 taxa spanning one decade of W/S for a verdict; a pooled fit is reported only as a secondary descriptive number and decides nothing.",
        "Thompson's claim is stated for a bird in powered level flight; applying v_min to a glider assumes only the lift balance W = 0.5 rho v^2 S C_L, which holds for any steady lift-supported flight. That is the sense in which it applies to gliders."
      ],
      "values_read_between_preregistration_and_amendment": [
        "Park and Choi 2010 Table 1 (five Cypselurus hiraii specimens: SL 199-209 mm, mass 0.04-0.06 kg, pectoral area 5498-7069 mm2, pelvic 1603-1837 mm2, body planform 4258-4640 mm2, span 233-261 mm, AR 9.0-10.7) and Table 2 (C_Lmax 0.78 at 35 deg, L/D max 4.37 at 0 deg, reference area A1+A2+A3); field flight speed 10-20 m/s quoted there from Hertel 1966, Fish 1990, Davenport 1994.",
        "Bahlman et al. 2013: Glaucomys sabrinus reference mass 92.7 g, published wing loading 59 N/m2 (Stafford et al.), average glide velocity 7.2 m/s over 18 m glides, launch 5.4 m/s; mammalian glider wing loadings 38-143 N/m2.",
        "Byrnes et al. 2008: Galeopterus variegatus 0.75-1.4 kg (mean 1.1 kg), asymptotic horizontal glide velocity 9.91-10.2 m/s (mean 10.1) for glides over 20 m, landing 3.99 m/s, take-off 0.61-8.2 m/s (mean 3.70).",
        "Davenport 1992 and 2003 abstracts: allometric exponents for Exocoetus obtusirostris (mass b=2.981, lateral fin area b=1.834, wing loading b=1.236 on standard length); no absolute values read.",
        "No bat or fly value had been read when this amendment was written."
      ]
    }
  ],
  "completed_at": "2026-10-31T18:36:55Z",
  "verdict_by_interpretation": {
    "A_gliders": "inconclusive",
    "A_powered": "inconclusive",
    "B": "inside",
    "C": "cannot-tell"
  }
}