S2.7.2 For the adult
Sound travels
How does a sound get from one place to another?
What this chapter teaches
Sound travels by passing a vibration through air, water or solids, so it cannot cross empty space. In air it goes about 340 metres each second.
Three questions to ask
There is no one right wording. Listen for the idea.
- How does the sound of a drum get from the drum to your ear?
- Why do you see lightning before you hear thunder?
- What do you think you would hear in empty space, and why?
After the chapter, the learner can
- Explain that sound travels through air, water and solids
- Compare a tap heard through air and through a table
- Explain that sound cannot travel through empty space
What they copy into their notebook
Sound travels by passing a vibration through air, water and solids. It cannot cross empty space. In air it goes about 340 metres each second. A table can carry a tap better than air.