声能:声音不会在真空中传播。我们把一个电铃放在一个封闭的钟里,然后把它放空。1925年的匿名插图。私人收藏。(Sound energy: sound does not spread in a vacuum. We put an electric bell in a closed bell and then we empty it. Anonymous illustration from 1925. Private collection.)匿名匿名 |
€ 98.15
Enthält 0% MwSt.
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日期不详 · Engraving
· 图片ID: 915769
Private Collection / Bridgeman Images |
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