Waves Unit 9 - Light & Sound
Lesson 1: Questions What are the similarities and differences between transverse and longitudinal waves? How is a wave s amplitude related to its energy? How are frequency and wavelength related?
Vocabulary Wave Medium Transverse Wave Crest Trough Longitudinal/Compressional Wave Compression Rarefaction Amplitude Wavelength Frequency
Waves Wave - a repeating motion that carries energy through space or a medium
Waves Medium - a material through which waves transfer energy
Waves Medium - a material through which waves transfer energy Can be a solid, liquid, gas, or combination The medium does not travel with the wave Not all waves need a medium! mechanical waves need a medium Light waves do not need a medium
Types of Waves Transverse Wave - the medium moves at a right angle or perpendicular to the direction the wave is traveling Ex: Light waves Medium Direction Direction of Energy
Structure of a Transverse Wave Crest - the highest point of a wave Trough - the lowest point of a wave Crest Crest Crest Rest Position Trough Trough Trough
Types of Waves Longitudinal/Compressional Wave - the medium vibrates in the same direction as the wave is traveling Ex. Sound waves Direction of Energy Medium Direction
Types of Waves Wave - a repeating motion that carries energy through space or a medium
Structure of a Compressional Wave Compression - crowded area of the wave Rarefaction - less crowded area of the wave Compression Rarefaction
Amplitude Amplitude - the distance from the rest position of the wave to a crest or trough Amplitude Rest Position Amplitude
Amplitude Amplitude - the distance from the rest position of the wave to a crest or trough Amplitude describes the energy or intensity of a wave HIGH amplitude = HIGH energy light wave = BRIGHT LOW amplitude = LOW energy light wave = DIM
Amplitude Amplitude - the distance from the rest position of the wave to a crest or trough Amplitude describes the energy or intensity of a wave HIGH amplitude = HIGH energy sound wave = LOUD LOW amplitude = LOW energy sound wave = SOFT
Wavelength Wavelength (λ) - the distance between two identical parts of a wave Measured crest to crest Measured trough to trough Crest Wavelength Crest Wavelength Trough Trough
Wavelength Wavelength (λ) - the distance between two identical parts of a wave Measured compression to compression Measured rarefaction to rarefaction Wavelength Wavelength
Frequency Frequency - the number of waves passing a point per second Units: Hertz (Hz) Describes the color/type of light HIGH frequency = Ex. UV Light Waves LOW frequency = Ex. Radio Waves
Frequency Frequency - the number of waves (# of vibrations) passing a point per second Units: Hertz (Hz) Describes the pitch of a sound HIGH frequency = HIGH PITCH sound LOW frequency = LOW PITCH sound
Frequency LIGHT SOUND High frequency = Short wavelength Wavelength Wavelength Low frequency = Long wavelength Wavelength Wavelength
What are the Units for Frequency? 1 Hertz means 1 Wave per Second
How does a wave travel? Through a medium,which is a substance or material that carries the wave. Ex: Liquid, Solid, Gas *The denser the material the faster sound will travel
What is an Electromagnetic Wave? The waves that are formed from electric and magnetic fields vibrating. They can travel through air, liquid, solids and the vacuum of outer space. *Does not NEED a medium!
What is the Electromagnetic Spectrum? The name given to a group of energy waves that are mostly invisible and can travel through empty space. Brain Pop on Electromagnetic Spectrum Video