| Title | |
|---|---|
 ,  ,  |
Optical Bench |
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Optical discs |
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Optical disk after Hartle |
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Orrery |
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Oscilloscope |
 ,  ,  ,  |
Ozone generator by Werner Von Siemens |
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Pair of bulbs after Violle |
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Pair of candlesticks |
 ,  ,  |
Paper cards with optical illusions |
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Papin's digester |