赤道で金を買って北極で売っても儲からない/enのソースを表示

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{{豆知識
|番号=0020
|本文=The idea that you can profit by buying gold where gravity is weak, at the equator, and selling it where gravity is strong, at the North Pole, does not work.
|なぜ=Trade is by mass, and scales used in trade are verified and adjusted to the gravity where they are used, so reweighing shows no difference.
|ジャンル=お金・制度
|ファクト度=C
|ファクト度の根拠=Rating of the claim that it makes a profit. The regulation of trade scales and their adjustment to the place of use are confirmed by primary sources (local government, the law, a weights-and-measures office), but the "profit from gold" idea itself is sourced only from a forum (tertiary)
|ネタ度=S
|ネタ度の根拠=The tempting idea of profiting from gravity, and the catch
|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=反証あり
|根拠1URL=https://www.city.takamatsu.kagawa.jp/kurashi/kurashi/sodan/shohi_seikatsu/kensa.files/hakari_kounyu.pdf
|根拠1要約=Notice from Takamatsu City. Scales used for trade (selling food by weight, buying precious metals) or certification are regulated by the Measurement Act
|根拠1格付け=一次
|根拠2URL=https://laws.e-gov.go.jp/api/2/law_data/404AC0000000051?response_format=json&law_full_text_format=json
|根拠2要約=Measurement Act (e-Gov law database). Article 16: a specified measuring instrument without a verification mark may not be used, or held for use, for measurement in trade or certification
|根拠2格付け=一次
|根拠3URL=https://www.tokyo.med.or.jp/wp-content/uploads/application/pdf/20251202-keiryouhou.pdf
|根拠3要約=Notice from the Tokyo weights-and-measures office. Scales have a designated area of use and may be used if the local gravitational acceleration is within the marked range
|根拠3格付け=一次
|根拠4URL=https://www.physicsforums.com/threads/weights-at-different-altitudes.713737/
|根拠4要約=Physics forum (2013). To the question whether you could make money buying gold at one altitude and selling it at another, the answer is that with a balance the counterweights get lighter by the same amount, so there is no difference
|根拠4格付け=三次
|補足=If you carried a spring scale with you, you would see a difference of about 0.5% between the equator and the North Pole (#0012). But scales used in trade are adjusted to local gravity ([[Special:MyLanguage/取引に使うはかりには使ってよい場所が書いてある|#0018]]), and an unadjusted scale may not be used in trade. Shipping the gold would cost far more anyway.
|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
}}