4. Wave, Pulse Wave and Periodic Wave
• WAVE – a disturbance or variation traveling through a
medium or a vacuum
• Pulse wave – a single traveling unrepeated disturbance
• Periodic Wave – succession of periodic disturbances
5. IMPORTANT
Waves are simply energy carriers. As the wave
travels through a medium, the energy it
carries is transmitted as vibrational energy
from one particle to another. The particles of
the medium do not move or go with wave.
6. WAVE Types:
1. MECHANICAL WAVES – waves that
requires a medium for propagation
Examples: sound waves, water waves
2. ELECTROMAGNETIC WAVES (EM) – waves
that can travel through a medium or
through vacuum
Examples: light, radio waves, gamma rays
7. Group Activity: Human Simulation
Discuss the following questions:
• What is a transverse/longitudinal wave?
• What is frequency? wavelength? amplitude?
Then, simulate your assigned wave using your own
bodies to show the following:
• wave with low frequency and low amplitude
• wave with high frequency and low amplitude
• wave with low frequency and high amplitude
• wave with high frequency and high amplitude
8. Group Activity: Human Simulation
Transverse:
• wave with low frequency
and low amplitude
• wave with high frequency
and low amplitude
• wave with low frequency
and high amplitude
• wave with high frequency
and high amplitude
Longitudinal:
• Wave with low frequency
• Wave with high frequency
• Wave with short
wavelength
• Wave with long wavelength
Then, simulate your assigned wave using
your own bodies to show the following:
9. Types of Mechanical Waves:
a. Transverse Waves – the particles of the
medium vibrates perpendicular to the
direction of the wave motion
b. Longitudinal Waves – the particles of
the medium vibrates parallel to the
direction of the wave motion
c. Surface Waves – combination of
transverse and longitudinal motion
15. WAVE Parameters
a. Compression - region of wave with highest pressure or density;
happens when molecules are forced, or pressed, together.
b. Rarefaction - region of wave with lowest pressure or density;
occurs when molecules are allowed to expand
19. General Properties
REFRACTION
The change in direction and change in wavelength or velocity of
waves (bending) as it passes through different medium or
through the same medium of varying temperatures.
21. General Properties
INTERFERENCE
The meeting or coming together of waves. Interference could
be CONSTRUCTIVE – waves reinforce each other or
DESTRUCTIVE – waves cancel each other. Interference may
also be described as partial or total.
22. WAVE Speed (v)
v = distance traveled by a wave / time taken
v = d / t
v = wavelength / period = λ / T
v = wavelength x frequency = λf
NOTE: EM waves travel through vacuum at 299,
792, 458 m/s or around 300 000 000 m/s
(3 x 108 m/s). This speed is considered to be the
speed of light in a vacuum denoted by the
letter c (c =3x108m/s.)
23. Sample Calculations
1. AM radio signals/waves (EM waves) have average wavelength
of around 370m. What is the frequency of this signal in Hz?
In kHz?
2. A swimmer notices that water wave crests pass his body
every 5s. His estimate of the distance between two crests is
3m. How fast are the waves traveling?
3. Light waves (EM waves) coming from the sun have
frequencies of 6 x 1014 Hz. If it will take this wave 8 minutes
to travel from the sun to the Earth, how far is the sun from
us?
4. A certain radio wave has a wavelength of 300m. What is the
frequency of this wave in Hz? In kHz?