<P> Electromagnetic radiation can be transmitted through an optical medium , such as optical fiber , or through twisted pair wires , coaxial cable , or dielectric - slab waveguides . It may also pass through any physical material that is transparent to the specific wavelength , such as water , air , glass , or concrete . Sound is , by definition , the vibration of matter , so it requires a physical medium for transmission , as do other kinds of mechanical waves and heat energy . Historically , science incorporated various aether theories to explain the transmission medium . However , it is now known that electromagnetic waves do not require a physical transmission medium , and so can travel through the `` vacuum '' of free space . Regions of the insulative vacuum can become conductive for electrical conduction through the presence of free electrons , holes , or ions . </P>
<P> Electromagnetic radiation can be transmitted through an optical medium , such as optical fiber , or through twisted pair wires , coaxial cable , or dielectric - slab waveguides . It may also pass through any physical material that is transparent to the specific wavelength , such as water , air , glass , or concrete . Sound is , by definition , the vibration of matter , so it requires a physical medium for transmission , as do other kinds of mechanical waves and heat energy . Historically , science incorporated various aether theories to explain the transmission medium . However , it is now known that electromagnetic waves do not require a physical transmission medium , and so can travel through the `` vacuum '' of free space . Regions of the insulative vacuum can become conductive for electrical conduction through the presence of free electrons , holes , or ions . </P>
which type of wave requires a medium for transmission
which type of wave requires a medium for transmission
Sound mechanical waves heat energy
Sound mechanical waves heat energy