He found that the length of time it takes a sound's echo to decay is determined by the absorption of the sound's original energy by surrounding material.
他发现，声音回声衰减的时间长短取决于周围物质对声音原始能量的吸收。
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The orderly nature of our solar system leads most astronomers to conclude that the planets formed at essentially the same time and from the same material as the Sun.
That gives them more time to absorb lectures via podcast or video, and frees teachers to spend class time coaching students in how to apply the material rather than simply absorb it.