An hourglass,or sand timer,is used to measure a set period of time by the flow of sand from one chamber to the other through a narrow gap | |
Lizenzart: | Lizenzpflichtig |
Credit: | Science Photo Library / Science Source |
Bildgröße: | 4121 px × 3076 px |
Modell-Rechte: | nicht erforderlich |
Eigentums-Rechte: | nicht erforderlich |
Restrictions: |
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