Waves and the Electromagnetic Spectrum 8 th Grade Physical Science.
WAVES Chapter 23 Physical Science REVIEW OF WAVES.
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Transcript of WAVES Chapter 23 Physical Science REVIEW OF WAVES.
WAVES
Chapter 23
Physical Science
REVIEW OF WAVES
Waves transfer what?
ENERGY!!!!
What are the two main types of waves?
• MECHANICAL WAVES
• ELECTROMAGNETIC WAVES
Which type of wave requires a medium?
MECHANICAL WAVESElectromagnetic waves do NOT
need a medium.
What are 3 examples of Mechanical Waves?
• Water waves
• Sound waves
• Seismic waves
What are some examples ofElectromagnetic Waves?
• Radio waves
• Microwaves
• Infrared light
• Visible light
• Ultraviolet light
• X-rays
• Gamma Rays
What are the colors of Visible Light?
• R O Y G B I V
R O Y G B I V
• RED
• ORANGE
• YELLOW
• GREEN
• BLUE
• INDIGO
• VIOLET
Which color is the HIGHEST energy wave?
• VIOLET
Which color is theLOWEST energy wave?
• RED
What 3 characteristics doAll Waves have?
• Amplitude
• Wavelength
• Frequency
What does the size of the amplitude of a wave tell us?
• HIGH AMPLITUDE = HIGH AMOUNTS OF ENERGY• LOW AMPLITUDE = LOW AMOUNTS OF ENERGY
What unit do we use to measure Wavelengths in?
• Meters
What greek letter do we useto represent a wavelength?
• Lambda
What are the 3 units we can use for Frequency of a wave?
• Waves / second
• Cycles / second
• 1/s = Hertz (Hz)
Name the 2 types of Mechanical waves.
• TRANSVERSE WAVES
• LONGITUDINAL WAVES
Which type of wave form crests and troughs?
• TRANSVERSE
Longitudinal wave do not have crests and troughs,
instead they have what?
• COMPRESSIONS
• RAREFACTIONS
How does the medium movewhen a longitudinal wave moves
through it?
• The medium vibrates horizontally.
Surface Waves move both horizontally and vertically
simultaneously, which produces what kind of movement?
• Circular
Speed of WavesWhat is the wave equation?
• V = f • speed = frequency times wavelength
The speed of a wave is held constant within a medium. So
what effect on the wavelength of a wave would you expect if the
frequency were doubled?• The wavelength would half as much.
When frequency goes up the wavelength must go down.
The density of water is 1 g/ml and the density of syrup is 3 g/ml. Which of the above would you
expect a wave to travel the slowest through?
• A wave would travel the slowest through the SYRUP.
• Waves travel slower through dense mediums.
A slinky is a very elastic object. Explain why this is used to
demonstrate wave motion instead of an object like a tree branch?
• A slinky has HIGH ELASTICITY !
• The higher the elasticity the higher the speed of a wave traveling through it.
Name the 4 ways waves interact.
• Reflection
• Refraction
• Diffraction
• Interference
Explain reflection of a wave.
• Bouncing back of a wave after it strikes a boundary.
Explain Refraction.• The change in path of a
wave when it moves into a medium of a different density.
Explain Diffraction.• The curving of waves around barriers and
ability of waves to spread out in circular pattern after passing through a narrow opening. See picture below.
What are the 2 types of Interference?
• Constructive
• Destructive
Which of the pictures below is an example of
Constructive Interference?
The picture on the left is constructive interference.The picture on the right is destructive interference.
Nodes and Antinodes are parts of what kind of wave?
• Standing Wave
The frequency at which a standing wave occurs is called
what?
• Resonant Frequency
• Sometimes called Natural Frequency.