富士山頂では体重計の数字が約0.1％軽く出る/enのソースを表示

<languages/>
{{豆知識
|番号=0015
|本文=Gravity weakens with height. Gravity on the summit of Mt Fuji is about 0.1% weaker than in Tokyo (measured in 1880), so a person who reads 80 kg in Tokyo reads about 80 g lighter at the summit.
|ジャンル=科学・自然
|ファクト度=A
|ファクト度の根拠=Confirmed with values from a primary source (the 1880 measurement paper). Not S because the measurement is old and a modern summit/foot pair of values was not obtained
|ネタ度=A
|ネタ度の根拠=People may have heard you weigh less on a mountain, but the actual number is a surprise
|便利度=該当なし
|便利度の根拠=A fact worth knowing for its own sake
|検証ステータス=根拠あり
|根拠1URL=https://ajsonline.org/api/v1/articles/64061-on-a-determination-of-the-force-of-gravity-at-the-summit-of-fujiyama-japan.pdf
|根拠1要約=Mendenhall, "On a Determination of the Force of Gravity at the Summit of Fujiyama, Japan" (American Journal of Science, 1881). Measured with a pendulum in August 1880: Tokyo 9.7984, summit 9.7886 m/s². The difference is 0.100%, or 80 g for 80 kg (checked by calculation)
|根拠1格付け=一次
|根拠2URL=https://www.jstage.jst.go.jp/article/sokuchi1954/6/1/6_1_12/_article/-char/en
|根拠2要約=Abstract of a paper in the Journal of the Geodetic Society of Japan (1960). A 1957 measurement gave 978.877 Gal at the summit of Mt Fuji, almost the same as the 1880 value (978.86 Gal)
|根拠2格付け=一次
|根拠3URL=https://www.gsi.go.jp/buturisokuchi/grageo_gravity
|根拠3要約=Explanation by the Geospatial Information Authority of Japan. At 1,000 m elevation the fourth digit of the gravity value is about 3 lower than at sea level (about 0.03%)
|根拠3格付け=一次
|補足=Calculating from height alone gives about 0.12% less at 3,776 m, but the mass of the mountain itself pulls downward, so the real difference is smaller. The comparison is with Tokyo, not the foot of the mountain, and includes a small latitude effect (about 0.3°). This applies to spring and electronic scales; a balance shows no difference.
|検証日時=2026-10-29
|検証方式=AI＋人
|本家既出チェック=未掲載
|派生元=体重計の数字は緯度が高いほど大きく出る
}}