INTRODUCTION
A vibration
(A ‘ middle point). A pendulum is an isolated object and helps us understand
what a vibration is.
Consider the picture above: What happens to the particles in the material of
the drum when someone beats a drum?
There are three types of waves:
MECHANICAL
WAVES
ELECTROMAGNETIC
WAVES
MATTER WAVES
A mechanical wave is
. A
is a
material that allows for the transmission of energy through
vibrations. The vibration of a particle is caused by the
. The net motion of a particle
is the displacement of a particle over a certain time
interval.
What Factors influence the ability of a medium to transfer waves?
PARTICLE BEHAVIOUR IN DIFFERENT MEDIA
Type of Media
Solid Media
Fluid Media
(Liquid)
Fluid Media (Gas)
Characteristics
- Particles in a solid medium held together by
________________________________________
- Particles are limited in their motion (vibrations)
even when disturbed
- Most solid media are _________, so they return to
their original shape after they are disturbed.
- Waves in solids travel _____________________
- Particles in a liquid medium are still in contact, but
not as much as in solids
- Liquids transmit _____________ very effectively
- Particles in a gas are much farther apart than solids
and liquids
- Gases exhibit _______________________
(straight-line motion of molecules)
- Gases are _______________ at transmitting
vibrations
There are 2 Types of Mechanical Waves:
TRANSVERSE WAVES

Examples:
LONGITUDINAL WAVES

Examples:
SURFACE WAVES

Refer to Complex Waves Below
LONGITUDINAL WAVES
Longitudinal waves exhibit regions in which the particles are either closer of farther apart. A
is a longitudinal wave region where the medium’s particles are
. In compressions, the pressure of the particles is
. A
is a longitudinal wave region where the medium’s particles are
. In rarefactions,
the pressure of the particles is
.
is a form of energy that is detectable to sensory organs (such as the ear). This
transfer of energy occurs only in
waves. Our brain interprets these wave
motions (with compressions and rarefactions) as sound.
COMPLEX WAVE MOTION

Certain situations involve the transmission of energy
through a
of waves, both transverse
and longitudinal.

Water waves appear to generally be transverse in
appearance. However, water waves are a large result of wind.
The wind assists in producing a
for water molecules allowing them to exhibit both types of
motion.
WEBLINKS for
MECHANICAL WAVES
HOMEWORK:
http://library.thinkquest.org/10796/ch8/ch8.htm
http://www.acs.psu.edu/drussell/demos/waves/wavemotion.html
Read Pages 378-380 and Complete Questions #1, 3-5 on Page 380
Read Pages 381-384 and Complete Questions # 1-3, 5-7 on Page 384