Waves

Waves
S8P4a: Identify the
characteristics of
electromagnetic and
mechanical waves.
EQ: Why can’t you hear sound
in space?
What is a wave?
• A disturbance or energy that travels
through a medium or empty space from
one location to another location
– A medium is any form of matter which
carries the waves
• The energy moves from one location
to another not the matter.
• There are two categories of waves:
Electromagnetic and Mechanical
Electromagnetic Waves
• Wave which is capable of transmitting its
energy through a vacuum (empty space).
Doesn’t need matter to transmit its
energy.
• Comes mainly from the sun
• EX: UV, infrared, visible light,
microwaves, x-rays, gamma rays, and
radio waves
• Most electromagnetic waves are
transverse
Transverse
• Vibrates perpendicular (at right angles) to
the wave travel
– Most electromagnetic waves are transverse
Animation courtesy of Dr. Dan Russell, Kettering University
Transverse
• Are Composed of
– Crests- The highest point of a wave
and
– Troughs- The lowest point of a wave
Mechanical Waves
• Are not capable of transmitting its energy
through a vacuum (empty space).
• Need or require a medium (matter) in
order to transport their energy from one
location to another
• EX: Sound waves, seismic waves, and
water waves
• Most mechanical waves are
compressional/longitudinal
Longitudinal/Compressional
• Vibrates parallel to (in the same direction of
wave travel ) the other end of the medium
without the actual movement of matter
--- Most mechanical waves are
longitudinal/compressional
Animation courtesy of Dr. Dan Russell, Kettering University
Longitudinal/Compressional
• Are composed of
– Compressions, where the parts of the
medium (coils of the Slinky) are closer
together than normal
and
– Rarefactions, where the parts of the
medium are farther apart than normal
Animation courtesy of Dr. Dan Russell, Kettering University
Water Waves
• A combination of longitudinal &
transverse
Animation courtesy of Dr. Dan Russell, Kettering University