Question

why the bells are made by metals insted of wood

Answer 1

Metals are sonorous. That means metals make a ringing sound when we strike them where as non metals like wood are not sonorous. They don't make ringing sound when we strike. Hence bells are made up of metals

Answer 2

Generally metals are sonorous that means they make soinfld after hitting them. Substances like wood lack this property. So, bells are made up of metals rather than wood.