SortStack #1778 — 2031-04-22

By weight · Order from lightest to heaviest.

1. A compact disc 15 g

   A CD's spiral data track is less than a micrometer wide and would stretch about five kilometers if unwound.

2. An average adult domestic cat 4.2 kg

   Cats purr at frequencies between 25 and 150 Hz — a range some studies suggest can promote bone and tissue healing.

3. An adult North American beaver 20 kg

   The largest beaver dam ever found, in Alberta, Canada, stretches about 850 meters and is visible from space.

4. An upright piano 220 kg

   Inside is a cast-iron plate holding strings at a combined tension of roughly 18 tonnes of pull.

5. A Holstein dairy cow 680 kg

   A productive dairy cow gives about 30 liters of milk a day — and burps enough methane to matter in climate accounting.

6. The Empire State Building 331K t

   Built in just 410 days during the Depression, it sat so empty at first that New Yorkers dubbed it the 'Empty State Building'.

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