1. Waves

2. Wave Energy
Wave-any disturbance that transfers energy from one place to another without transferring matter
transfer energy AWAY from the source of the energy
Medium – material through which wave energy is transferred
waves travel fastest through solids because molecules are closer together

3. Mechanical Waves
Mechanical Waves – a wave that can travel only through matter. (They need a medium-(solid, liquids, or gasses)
Types of Mechanical Waves:
Sound Waves- (longitudinal waves)
Water Waves- (orbital waves)
Seismic Waves-( longitudinal and transverse)

4. Mechanical Waves - Transverse
Transverse Waves:
the disturbance is perpendicular to the direction the wave travels
move in an up-and-down motion
top of the wave is called the crest and the base of the wave is called the trough

5. Mechanical Waves - Longitudinal
Longitudinal Waves
the disturbance moves parallel to the direction the wave travels
move in a back-and-forth motion
where particles are crowded together is called the compression, where they are farther apart is called the rarefaction

6. Mechanical Waves – Orbital
Orbital Waves-(Surface waves)
combination of a transverse wave and a longitudinal wave
ocean waves are an example of surface waves
the water moves up and down while the wave energy moves forward
objects in an ocean wave bob up and down in a circular motion

7. WRITING RESPONSE
What do waves transfer from place to place? What kind of materials can mechanical waves move through?

9. Electromagnetic (EM) Waves
Electromagnetic Waves (EM) – can travel through empty space and through matter; does NOT need a medium
All electromagnetic waves are transverse
ex. light waves, x-rays, ultraviolet waves, microwaves, radio waves
The type of EM waves given off by an object depends mainly on the temperature of the object
Ex: humans give off infrared rays

10. PROPERTIES OF WAVES

11. Amplitude – the height of a wave, from resting position to crest
the larger the amplitude, the more energy the wave has
Wavelength – distance from any point on a wave to an identical point on the next wave
the shorter the wavelength, the more energy the wave has

12. shorter wavelength = more energy
higher amplitude = more energy

13. Wave Speed – the speed at which a wave travels
Frequency – the number of waves produced in a given amount of time; measured in hertz (Hz)
1 Hz = 1 wave per second
frequency and wavelength are inversely related, which means as one decreases the other increases (and vice versa)
Wave Speed – the speed at which a wave travels
to calculate: wave speed (s) = frequency (f) x wavelength (λ)
s = f x λ

14. higher frequency = shorter wavelength = more energy

15. Wave Speed Calculations
1) Determine the wave speed of a wave that has a wavelength of 5 m and a frequency of 4 Hz.
s = f x λ = 4 Hz x 5m = 20 m/s
2) What is the speed of a wave that has a wavelength of 2 m and a frequency of 6 Hz?
3) What is the frequency of a wave if the wave has a speed of 12 cm/s and a wavelength of 3 cm?

16. Wave Speed Calculations
2) What is the speed of a wave that has a wavelength of 2 m and a frequency of 6 Hz?
s = f x λ
s= 6 Hz x 2m
s= 12 m/s
3) What is the frequency of a wave if the wave has a speed of 12 cm/s and a wavelength of 3 cm?
12 cm/s= f x 3cm
f= 4 Hz

17. WRITING RESPONSE
When comparing a category 3 hurricane and a category 5 hurricane, which hurricane will create water waves with the most amplitude? Why?

18. WRITING RESPONSE
When comparing a category 3 hurricane and a category 5 hurricane, which hurricane will create water waves with the most amplitude? Why?
A category 5 hurricane will create water waves with the most amplitude because it carries more energy

19. WAVE INTERACTIONS

20. Wave Interactions
Absorption – the transfer of energy by a wave to the medium through which it travels
ex. air absorbs sound, dark objects absorb light
Transmission – the passage of light through an object, like a window

21. Reflection – the bouncing of a wave off a surface
ex. sound wave reflection is called an echo
Normal – line perpendicular to the surface
Angle of Incidence – angle between the incoming wave and the normal
Law of Reflection - when a wave is reflected from a surface, the angle of the reflection is equal to the angle of incidence

23. Wave Interactions
Refraction – the change in direction of a wave that occurs as the wave changes speed when moving from one medium to another
ex. light waves are refracted when they pass from air to rain drops, and a rainbow is formed

24. Wave Interactions
Diffraction – the change in direction of a wave when it travels by the edge of an object or through an opening
ex. music around a corner

25. Wave Interactions
Interference – occurs when waves that overlap combine, forming a new wave
Constructive Interference – when two crests or two troughs combine, therefore combining the energy, and making a larger crest or trough
Destructive Interference – when the crest of one wave meets the trough of another wave, resulting in no wave at all
Standing Wave – two waves of the same wavelength overlap and the wave seems to be standing still

26. WRITNG RESPONSE
How do waves change as they pass from one medium to another? Compare and contrast reflection, refraction, and diffraction.

27. WRITNG RESPONSE
How do waves change as they pass from one medium to another?
Waves bend or change direction because their speed changes as they pass through one medium to another
Compare and contrast reflection, refraction, and diffraction.
Reflection, refraction, and diffraction are all ways waves interact with matter. Reflection occurs when a wave strikes a surface and bounces off. Refraction occurs when a wave changes direction as it passes from one medium to another. Diffraction occurs when waves change direction as they pass by the edge of an object or through an opening.