5. Are seismic waves (waves throughout the Earth's crusty mechanical waves? How about sound? Light (electromagnetic waves)? In each case , if the wave is a mechanical wave, identify the medium.

Yes, seismic waves are mechanical waves. They propagate through the Earth's crust, mantle, and core by causing particles within these layers to vibrate. The **medium** for seismic waves is the Earth itself (rock, magma, etc.).<br /><br />Sound is also a mechanical wave. It requires a medium to travel through, as it propagates by causing vibrations in the particles of the medium. The medium for sound can be various substances like air, water, solids, etc.<br /><br />Light, however, is *not* a mechanical wave. Light is an electromagnetic wave. Electromagnetic waves, unlike mechanical waves, do *not* require a medium to propagate. They can travel through the vacuum of space. Therefore, there is no medium for light waves.<br />