Transcript TOPIC: Waves AIM: What is a wave?

TOPIC: Energy
AIM: Describe the characteristics of
waves.
Do Now: Review Question #1 on 2nd page
of KE and PE reading notes
HW: CL Energy due Tuesday, Energy Exam
on Wednesday
If both of these balls are traveling down a bowling
lane at the SAME speed, which one would
have more kinetic energy? Support your answer.
Ball A.
It has a greater
mass.
1. Define
the term
wave.
• Traveling disturbance that
carries energy from one
place to another
• REPEATING disturbance
2. Describe • VIBRATIONS
the cause
• Any movement that
of waves.
follows the same path
repeatedly
Slinky waves can be made by
vibrating the coil back & forth in
either a horizontal or a vertical
direction.
3. Define a • The movement of energy
wave
from a vibrating source.
using the
terms
energy
and
vibrating.
A pebble tossed into the water will create a circular
disturbance which travels outwards in all directions. The
pebble transfers some of its energy to nearby water
molecules causing them to move. These water molecules
transfer this energy to molecules around them.Energy is
traveling in the form of a wave on the surface of the
water.
A tuning fork forces air particles
to vibrate creating sound.
4. Identify • MEDIUM
the
matter
waves
pass
through.
5. Identify a. Ocean Waves
the
WATER
medium
for the
following
waves:
b. Sound waves
AIR
6. Describe the
main difference
between
mechanical and
electromagnetic
waves.
• Mechanical waves
require a medium
– Ex: Sound waves
– Sound can’t be heard in
outer space
– Why???
• Bc outer space is a
vacuum
• Electromagnetic
waves does not
require a medium
The sound produced by the bell
cannot be heard since sound can’t
travel through a vacuum. It is a
mechanical wave.
•
Region
where
no
matter
Vacuum
exists
• Example: outer space
7. Identify the 3
characteristics
that all waves
have.
• Amplitude
• Wavelength
• Frequency
Normal resting
position
Crest
Trough
•Crest – high points
•Trough – lowest
points
Amplitude
•Amplitude – height
–Distance from
crest/trough to rest
–High amp = a lot of
energy
A
B
Which waves have a high amplitude?
Wavelength
• Wavelength – distance bw 2
crests or 2 troughs
A
B
Which waves have a shorter wavelength?
• Frequency:
• # of complete waves per unit of
time
A
B
Which waves have a higher frequency?
A
B
Which waves have a shorter wavelength?
11. How are • Transverse
waves
• Longitudinal
classified?
Can you see the difference between these
two waves? Hint…look at the movement
of the particles (medium).
12. Describe • Motion of particles is at
the motion RIGHT ANGLE to the
of the
direction of the wave.
medium in
a
transverse
wave.
Direction of
particles
Direction of wave
(PERPENDICULAR)
13. Identify • Wave on a rope
examples
• Light and other
of
electromagnetic
waves
transverse
• Ocean waves
waves.
14. Describe • Particles of medium
the motion
move PARALLEL to the
of the
direction of the wave
medium in a
longitudinal • Compressional waves
wave.
15. Describe • Series of compressions
what a
and rarefactions
longitudinal
wave
consists of.
Direction of
particles (left &
right)
Direction of wave
(BACK AND FORTH)
16. Describe
the
difference
between a
rarefaction
and a
compression.
• Rarefaction: space in medium where there are
fewer particles
• Compression: space in medium where particles
are crowded together
rarefaction
A
B
compression
B
A
C
D
E
F
17. Identify • Sound waves
an example
of a
longitudinal
wave.
Forces in Earth’s crust can cause regions of the crust to
shift, bend, or even break. The breaking crust vibrates,
creating seismic waves that carry energy outward. Seismic
waves are a combination of compressional and transverse
waves. They can travel through Earth and along Earth’s
surface. The more the crust moves during an earthquake,
the more energy is released.
Let’s summarize…
1.What is a wave?
2.Identify the cause of waves.
3.Describe a medium.
4.Identify an example of a medium.
5.Describe a vacuum.
6.Explain the difference between mechanical and
electromagnetic waves.
7.Explain the difference between transverse and
longitudinal waves.
8.Identify an example of a mechanical wave,
electromagnetic wave, transverse wave and
longitudinal wave.
Any substance through which a
wave can travel is called a
1.solid
2.vacuum
3.medium
4.liquid
Waves transfer
1.energy
2.matter
3.particles
4.heat
Which of the following is the best
example of a wave?
1.A stone rolling downhill
2.A vehicle moving on a bumpy
road
3.A string vibrating on a guitar
4.A grasshopper jumping up and
down
Which of the following statements applies to
longitudinal waves?
1.The motion of the medium is random.
2.The motion of the medium is in a circular
pattern.
3.The motion of the medium is parallel to the
motion of the wave.
4.The motion of the medium is perpendicular
to the motion of the wave.
Sound reaches our ears because
sound makes particles
1.heat up.
2.slow down.
3.cool down.
4.vibrate.
The distance between the Earth and the moon
was determined by measuring the time it took for
light waves from the Earth to travel to the moon
and back. Why was it not possible to use sound
waves for this experiment?
1.Sound waves must move through a substance.
2.Sound waves change frequency on the return
to earth.
3.Sound waves move too slowly for this
technique to be accurate.
4.Sound waves move more slowly in the Earth’s
atmosphere than in space.
A large spring is stretched horizontally between 2
people. One person wiggles the spring up and
down at one end. The up-and-down vibration then
moves along the spring on to the other person.
Which of the following type of wave is created in
the spring?
1.pressure wave
2.longitudinal wave
3.transverse wave
4.nonmechanical wave