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WAVE 
Physics Power Points 
CHARACTERISTICS 
Physics I 
Mr. Young 
www.pedagogics.ca
What is a wave?
What is a wave? 
a pattern of disturbances (oscillations, 
vibrations) caused by the movement of 
energy through matter or...
What is a wave? 
a pattern of disturbances (oscillations, 
vibrations) caused by the movement of 
energy through matter or...
What is a wave? 
a pattern of disturbances (oscillations, 
vibrations) caused by the movement of 
energy through matter or...
Waves can be classified according to their nature. 
Mechanical waves 
Electromagnetic waves
Waves can be classified according to their nature. 
Mechanical waves 
require a medium (matter) to travel through 
Sound w...
Waves can be classified according to their nature. 
Mechanical waves 
require a medium (matter) to travel through 
Sound w...
Waves can be classified by direction of vibration 
Transverse waves 
Longitudinal waves
A wave where the medium particles vibrate at 
right angles to the direction of energy 
transfer is called a transverse wav...
Waves can be classified by direction of vibration 
Tranverse waves 
direction of energy transfer 
direction of vibration 
...
Sound is an example of longitudinal wave 
A tuning fork causes 
surrounding air molecules 
to vibrate back and forth. 
Dir...
Waves can be classified by direction of vibration 
Transverse waves 
direction of energy transfer 
direction of vibration ...
Wave pulses travel through a medium and 
therefore transfer energy. 
Particles in the medium are moved back and 
forth by ...
Observing Waves Activity
crest 
trough
crest 
trough 
wave front
crest 
trough 
wave front 
ray
crest 
wave 
front 
trough 
ray
Adjusting Frequency 
Water droplets hitting the surface create 
disturbances (ripples) which move outward 
from the source...
What happens when frequency is increased? 
The rate of water droplets falling increases 
 creates more 
disturbances per ...
On a plot:
More drops per 
second, more waves 
per second, waves 
are closer together.
What happens when 
the amplitude of the 
source (drops) is 
increased? 
This would be caused 
by the drops hitting 
the wa...
Increasing the height or size of the falling 
water droplet is a BIGGER disturbance. 
What changes? 
The height of the rip...
A cork placed in the dish will bob up and 
down as the waves passed by. 
The relative position of the cork does not 
chang...
You can think of the cork as representing a 
molecule of water (the medium) 
So, the relative position of water molecules ...
KEY CONCEPT 
Waves transfer ENERGY not matter!
Describing Waves 
Waves are created by vibrating objects 
ONE vibration = ONE cycle = ONE oscillation 
(all describe one c...
PERIOD: the time required for one vibration. 
Measured in seconds. The symbol for period is T. 
푻 = 
풕풊풎풆 (풔) 
풏풖풎풃풆풓 풐풇 풗...
WAVELENGTH: How far the wave energy travels 
in one complete vibration. 
This is the distance traveled in an amount of 
ti...
Wavelength is measured as the distance 
between identical points on two successive 
waves.
AMPLITUDE: a measure of the maximum 
distance the particles in the medium are 
displaced from their resting position as th...
AMPLITUDE: a measure of the maximum 
distance the particles in the medium are 
displaced from their resting position as th...
Activity 2 – Examining Wave Motion in a 
Slinky Spring
A continuous wave is produced when a 
series of pulses are generated by a 
vibrating source. 
One shake produces a 
single...
Longitudinal pulses can be produced by 
holding spring coils together at one end and 
then releasing. 
A continuous wave c...
Longitudinal pulses can be produced by 
holding spring coils together at one end and 
then releasing. 
A continuous wave c...
Using Graphs to Describe Waves
Displacement – Position Graphs 
A displacement – position plot shows the 
different position of a particles in the medium ...
1.5 
1 
0.5 
0 
-0.5 
-1 
-1.5 
position 
displacement 
The graph shows the displacement of the rope 
at an instant in tim...
1.5 
1 
0.5 
0 
-0.5 
-1 
-1.5 
position 
displacement 
In transverse waves, the maximum and 
minimum displacements are ca...
Longitudinal waves are a bit tricky to understand 
because the direction of vibration is not 
perpendicular to the directi...
1.5 
1 
0.5 
0 
-0.5 
-1 
-1.5 
position 
displacement 
In longitudinal waves, the maximum and 
minimum displacements are ...
Displacement-Time Graphs 
A displacement – time plot shows how the 
position of a particle in the medium changes 
as it vi...
Amplitude can be measured on the y-axis. 
1.5 
1 
0.5 
0 
-0.5 
-1 
-1.5 
time 
displacement 
Period can be measured on th...
Wave Speed 
The speed of a wave is determined by the 
properties of the medium it travels through. 
Properties include:
Wave Speed 
The speed of a wave is determined by the 
properties of the medium it travels through. 
Properties include: 
•...
Recall: 
The definition of period 
The definition of wavelength
Recall: 
The definition of period 
the time it takes to complete one 
vibration/oscillation/cycle 
The definition of wavel...
So: 
wavelength 
wave speed= 
period
So: 
wavelength 
wave speed= 
?period
wavelength 
wave speed= 
period 
Try this: 
Use frequency instead of period and derive the 
wave speed equation. Write the...
Practice: 
1. Find the speed of a wave in a metal spring if 
a pulse travels 7.5 m in 3.0 s. 
2. What is the frequency of ...
Unit 4 2014  ppt    wave characteristics
Unit 4 2014  ppt    wave characteristics
Unit 4 2014  ppt    wave characteristics
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Unit 4 2014 ppt wave characteristics

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Unit 4 2014 ppt wave characteristics

  1. 1. WAVE Physics Power Points CHARACTERISTICS Physics I Mr. Young www.pedagogics.ca
  2. 2. What is a wave?
  3. 3. What is a wave? a pattern of disturbances (oscillations, vibrations) caused by the movement of energy through matter or space
  4. 4. What is a wave? a pattern of disturbances (oscillations, vibrations) caused by the movement of energy through matter or space
  5. 5. What is a wave? a pattern of disturbances (oscillations, vibrations) caused by the movement of energy through matter or space
  6. 6. Waves can be classified according to their nature. Mechanical waves Electromagnetic waves
  7. 7. Waves can be classified according to their nature. Mechanical waves require a medium (matter) to travel through Sound waves, water waves, ripples in strings or springs are all examples of mechanical waves. Electromagnetic waves
  8. 8. Waves can be classified according to their nature. Mechanical waves require a medium (matter) to travel through Sound waves, water waves, ripples in strings or springs are all examples of mechanical waves. Electromagnetic waves do not require a medium (matter) to travel through – they can travel through space (a vacuum) Radio waves, visible light, x rays
  9. 9. Waves can be classified by direction of vibration Transverse waves Longitudinal waves
  10. 10. A wave where the medium particles vibrate at right angles to the direction of energy transfer is called a transverse wave. Look carefully at the motion of ONE of the particles in this transverse wave!
  11. 11. Waves can be classified by direction of vibration Tranverse waves direction of energy transfer direction of vibration Longitudinal waves
  12. 12. Sound is an example of longitudinal wave A tuning fork causes surrounding air molecules to vibrate back and forth. Direction of sound travel Look carefully at the motion of ONE of the particles in this longitudinal wave!
  13. 13. Waves can be classified by direction of vibration Transverse waves direction of energy transfer direction of vibration Longitudinal waves direction of vibration direction of energy transfer
  14. 14. Wave pulses travel through a medium and therefore transfer energy. Particles in the medium are moved back and forth by each pulse but are not transferred from one place to another. direction of energy transfer Vibration of metal atoms in the spring (the medium) BIG IDEA! WAVES TRANSFER ENERGY NOT MATTER!
  15. 15. Observing Waves Activity
  16. 16. crest trough
  17. 17. crest trough wave front
  18. 18. crest trough wave front ray
  19. 19. crest wave front trough ray
  20. 20. Adjusting Frequency Water droplets hitting the surface create disturbances (ripples) which move outward from the source.
  21. 21. What happens when frequency is increased? The rate of water droplets falling increases  creates more disturbances per unit time. Each disturbance has less time to travel before the next is created – so ripples are closer together
  22. 22. On a plot:
  23. 23. More drops per second, more waves per second, waves are closer together.
  24. 24. What happens when the amplitude of the source (drops) is increased? This would be caused by the drops hitting the water with more force.
  25. 25. Increasing the height or size of the falling water droplet is a BIGGER disturbance. What changes? The height of the ripples increases. What stays the same? The distance between the wavefronts
  26. 26. A cork placed in the dish will bob up and down as the waves passed by. The relative position of the cork does not change.
  27. 27. You can think of the cork as representing a molecule of water (the medium) So, the relative position of water molecules does not change (only motion is up and down)
  28. 28. KEY CONCEPT Waves transfer ENERGY not matter!
  29. 29. Describing Waves Waves are created by vibrating objects ONE vibration = ONE cycle = ONE oscillation (all describe one complete back and forth motion) FREQUENCY: the number of vibrations each second. Measured in s-1 (or Hertz). The symbol for frequency is f. A frequency of 12 Hz means that there are 12 complete waves generated each second! 풇 = 풏풖풎풃풆풓 풐풇 풗풊풃풓풂풕풊풐풏풔 풕풊풎풆 (풔)
  30. 30. PERIOD: the time required for one vibration. Measured in seconds. The symbol for period is T. 푻 = 풕풊풎풆 (풔) 풏풖풎풃풆풓 풐풇 풗풊풃풓풂풕풊풐풏풔 푻 = ퟏ 풇 풇 = ퟏ 푻
  31. 31. WAVELENGTH: How far the wave energy travels in one complete vibration. This is the distance traveled in an amount of time equal to the period of the wave. The symbol for wavelength is the Greek letter lambda (l).
  32. 32. Wavelength is measured as the distance between identical points on two successive waves.
  33. 33. AMPLITUDE: a measure of the maximum distance the particles in the medium are displaced from their resting position as the wave passes. Direction of Energy transfer transverse vibration longitudinal vibration It is easier to visualize these characteristics by looking at plots
  34. 34. AMPLITUDE: a measure of the maximum distance the particles in the medium are displaced from their resting position as the wave passes. Direction of Energy transfer transverse vibration longitudinal vibration It is easier to visualize these characteristics by looking at plots
  35. 35. Activity 2 – Examining Wave Motion in a Slinky Spring
  36. 36. A continuous wave is produced when a series of pulses are generated by a vibrating source. One shake produces a single vibration (a wave pulse). If the end of the spring is shaken back and forth, a continuous series of pulses is produced. This is a standing wave pattern.
  37. 37. Longitudinal pulses can be produced by holding spring coils together at one end and then releasing. A continuous wave can be produced by sliding the end of the spring back and forth towards your partner (holding the fixed end)
  38. 38. Longitudinal pulses can be produced by holding spring coils together at one end and then releasing. A continuous wave can be produced by sliding the end of the spring back and forth towards your partner (holding the fixed end)
  39. 39. Using Graphs to Describe Waves
  40. 40. Displacement – Position Graphs A displacement – position plot shows the different position of a particles in the medium at a given time for a section of the wave. Consider a rope that is being vibrated at one end. If we took a snapshot with a camera it might look like this.
  41. 41. 1.5 1 0.5 0 -0.5 -1 -1.5 position displacement The graph shows the displacement of the rope at an instant in time.
  42. 42. 1.5 1 0.5 0 -0.5 -1 -1.5 position displacement In transverse waves, the maximum and minimum displacements are called crests and troughs respectively. The distance between two successive crests OR troughs would be the wavelength crest l trough
  43. 43. Longitudinal waves are a bit tricky to understand because the direction of vibration is not perpendicular to the direction of wave travel. Consider the following images compression rarefaction l
  44. 44. 1.5 1 0.5 0 -0.5 -1 -1.5 position displacement In longitudinal waves, the maximum and minimum displacements are called compressions and rarefactions respectively. The distance between centers of two successive compressions OR rarefactions would be the wavelength center of compression l center of rarefaction
  45. 45. Displacement-Time Graphs A displacement – time plot shows how the position of a particle in the medium changes as it vibrates back and forth. Transverse and longitudinal waves look the same on this type of plot. The only difference is the direction of the particle displacement. 1.5 1 0.5 0 -0.5 -1 -1.5 time displacement
  46. 46. Amplitude can be measured on the y-axis. 1.5 1 0.5 0 -0.5 -1 -1.5 time displacement Period can be measured on the x-axis. The period would be the time for one complete wave.
  47. 47. Wave Speed The speed of a wave is determined by the properties of the medium it travels through. Properties include:
  48. 48. Wave Speed The speed of a wave is determined by the properties of the medium it travels through. Properties include: • type of material • elasticity • tension • density (solid, liquid or gas) • temperature Speed is calculated using the following equation. distance speed= time
  49. 49. Recall: The definition of period The definition of wavelength
  50. 50. Recall: The definition of period the time it takes to complete one vibration/oscillation/cycle The definition of wavelength the distance a wave travels in a complete vibration/oscillation/cycle
  51. 51. So: wavelength wave speed= period
  52. 52. So: wavelength wave speed= ?period
  53. 53. wavelength wave speed= period Try this: Use frequency instead of period and derive the wave speed equation. Write the equation using appropriate symbols.
  54. 54. Practice: 1. Find the speed of a wave in a metal spring if a pulse travels 7.5 m in 3.0 s. 2. What is the frequency of this wave if the distance between two successive wave crests is 0.25 m? 3. Challenge: A fisherman passes the time by counting waves passing under his boat. He notices that his boat rises and falls 8 times in 65 seconds. He counts 6 wave crests between his boat and a buoy located 54 m away. What is the speed of the water waves?

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