Sound travels through the air.
声音是通过空气传播的。
In the air, sound travels about 340 meters every second.
在空气中，声音每秒大约跑340米。
That is faster than a racing car.
这比赛车还要快。
But light is much, much faster.
但是光要快得多得多。
That is why we see lightning before we hear thunder.
所以我们总是先看到闪电，再听到雷声。
Sound travels fastest in solids.
声音在固体里传得最快。
Sound cannot travel in empty space.
声音在太空里传不出去。
Space is silent.
太空是寂静无声的。
