Waves, Sound, and Physical Optics

They are disturbances that require a medium to travel.

They are oscillating electric and magnetic fields propagating through space.

They are longitudinal waves caused by pressure variations.

They are stationary waves that do not transfer energy.

Sound waves

Water waves

Electromagnetic waves

Seismic waves

Stars emit mechanical waves that travel through space.

Electromagnetic waves can propagate through the vacuum of space.

The Earth's atmosphere acts as a medium for light to travel.

Stars are close enough that light doesn't need a medium to travel.

Red

Green

Blue

Violet

Red, green, blue

Blue, green, red

Green, blue, red

Red, blue, green

Electromagnetic waves require a medium, while mechanical waves do not.

Electromagnetic waves are longitudinal, while mechanical waves are transverse.

Electromagnetic waves can travel through a vacuum, while mechanical waves cannot.

Electromagnetic waves travel slower than mechanical waves.

They are all parallel to each other.

The electric and magnetic fields are parallel, but perpendicular to the direction of propagation.

The electric and magnetic fields are perpendicular to each other and to the direction of propagation.

The electric field is perpendicular to the magnetic field, but parallel to the direction of propagation.

+z direction

-x direction

+y direction

-y direction

Radio waves, because they easily penetrate soft tissue.

Microwaves, because they have a high thermal effect.

X-rays, because they are highly energetic and can be absorbed by dense materials like bone.

Infrared, because they can detect heat signatures.

Microwaves, visible light, X-rays

X-rays, visible light, microwaves

Visible light, microwaves, X-rays

X-rays, microwaves, visible light