9/14 p. 18 Waves Introduction Notes IQ: Put a check mark by things that you think involve wave action: Sun’s rays Musical instruments Earthquake Radios Water

Waves A wave is any disturbance that transmits/moves energy through matter or space through vibrations. A wave is energy, not matter being moved from one place to another.

Waves You can sometimes see a wave start. The energy moves out in all directions from the source.

The waves on the pond move toward the shore, but the water & the fishing lure floating on the surface don’t move w/the wave

Waves We draw waves to represent energy. If you vibrate a string, you demonstrate a wave. A vibration is a back and forth movement of an object. videovideo

The material a wave travels through is called a medium. Ex. Water (liquid) Air (gas) Ground (Solid)

Mechanical vs. Electromagnetic Waves that NEED a medium to travel are called Mechanical waves. Ex. Sound, ocean waves. Could be transverse or longitudinal. Waves that can travel without a medium are Electromagnetic waves. Ex. light, x-rays, microwaves. Always transverse.

EM Waves Require no medium to travel Can go through space. Light/EM waves How do we know EM/light waves can go through space? (answer on pg ) Mechanical Waves Require a medium to travel Can only go through a solid, liquid, or gas. Sound, slinky seismic & water are all examples Knowing this, what’s wrong/incorrect w/most SciFi movies, such as Aliens?! (answer on pg )

Types of Waves 1.Transverse Waves: particles move with an up and down motion, perpendicular to the direction of the wave. Ex. light waves. Video This is drawn like this:

Parts of a Transverse Wave A = Crest: highest pt. of wave B = Trough lowest point of wave D = 1 full wave = 1 wavelength C = Amplitude: height of wave C A B D

Parts of a T Wave

Types of Waves 2. Longitudinal waves/compressional waves: Particles move back and forth, (parallel) in the same direction as the wave’s energy. Ex. sound waves.

Parts of a Longitudinal Wave Compression: particles are pushed close together. Rarefaction: particles are spread apart. VideoVideo

Water waves Water waves have transverse and longitudinal characteristics. Energy is transferred, but the particles stay essentially in the same place

OQ: True or false: Waves transfer energy from one place to another and not particles.

Waves A _________ is any disturbance that transmits/moves _________through _______ or ________ through vibrations. A wave is energy, ______________. being _________ from one place to another.

Waves You can sometimes see a wave start. The energy ________ out in all ___________ from the _________.

Waves We draw waves to represent energy. If you vibrate a string, you demonstrate a wave. A wave/___________is a ______ and ________ movement of an object.

The _________ a wave travels ______ is called a ________. Ex. Water (_______) Air (_____) Ground (______)

Mechanical vs. Electromagnetic Waves that _______ a ______ to travel are called ____________waves. Ex. ________, ocean waves. Could be transverse or longitudinal. Waves that can travel without a medium are ______________ waves. Ex. ______, x-rays, microwaves. Always transverse.

EM Waves Require ________ to travel Can go through ________ Light/EM waves How do we know EM/light waves can go through space? (answer on pg ) Mechanical Waves _______ a medium to travel Can only go through a solid, liquid, or gas. ______, slinky, seismic & water are all examples Knowing this, what’s wrong/incorrect w/most SciFi movies, such as Aliens?! (answer on pg )

Types of Waves 1._____________Waves: particles move with an up and down motion, ___________ to the _________ of the ______. Ex. light waves. This is drawn like this:

Parts of a Transverse Wave A =____________ : highest pt. of wave B = ________ lowest point of wave D = 1 ______ __________ = 1 ____________ C = ________: height of wave C A B D

Parts of a T Wave

Types of Waves 2. ________________ waves/compressional waves: Particles move ______ and _________, (___________) in the same direction as the wave’s energy. Ex. __________ waves.

Parts of a Longitudinal Wave _____________: particles are pushed __________ ___________ _______________: particles are _______ ______. Copy diagram:

OQ: True or false: Waves transfer energy from one place to another and not particles.

9/15 p. 20 Wave Properties Notes IQ: Which wave has a larger amplitude? How can you tell?

Wave Properties Amplitude- The distance from the rest position to the top of a crest, or from the rest position to the bottom of a trough. Measure amplitude of the following wave: Wavelength- The length of one whole crest and one whole trough= 1 full wave Measure amplitude and wavelength of Following wave.

Frequency- The number of full waves passing through a point in one second. SI Unit is hertz. Ex. 10 waves per second = 10 hertz What is the frequency if 100 waves pass through a point in 20s?

Period: The amount of time it takes one wave to pass through a point. Inversely related to f. T=1/f Unit sec.

Speed- The distance travelled by a wave in a given amount of time, depends ONLY upon the medium. Ex. 100 meters in one second = 100 m/s. Speed= dist./time What is the speed of a wave that travels 50 m in 5 secs?

Wave Speed The Wave Speedpeed ttravels – ie: distance a crest or compression goes in a certain amount of time Depends on the medium the wave’s traveling through – Due to density variations – > dense = faster sound slower light – < dense = faster light slower sound Calculating wave speed: Wave speed (v) Wavelength (Λ) Frequency (f) v = Λ X f Unit = meters/sec (m/s)

Wave speed (v) Wavelength (Λ) Frequency ( f ) Speed= ____ x f Wavelength = ____ / f Frequency = v / _____ What is the frequency of a wave that is 2 m long and going at 10 m/s?

Frequency Large wavelength = low frequency Medium wavelength = medium frequency Small wavelength = high frequency

Frequency Don’t confuse the frequency with the speed of a wave. Here’s an analogy:

Frequency If you were looking down on a freeway... And all of the vehicles were going exactly 60 miles per hour (the same speed)...

Frequency Small cars going 60 miles per hour

Frequency Bigger cars going 60 miles per hour

Frequency Really big vehicles going 60 miles per hour

Frequency Speed = 60 miles per hour Small cars = high frequency (6) Bus = low frequency (1)

Frequency Light speed = 186,000 miles per second Blue light waves = higher frequency Red light waves = lower frequency

OQ: True or false? A wave with less frequency can be travelling faster than a wave with higher frequency.

Wave Properties _______________- The _____________ from the _______position to the ______ of a ________, or from the rest position to the ______ of a trough. ______________- The length of one ________ ______ and one ________ _______= 1 full wave

_______________- The number of full _________ passing through a point in one __________. SI Unit is __________ Ex. 10 waves per second = 10 hertz What is the frequency if 100 waves pass through a point in 20s?

___________: The amount of ________ it takes one wave to ________ through a point. Inversely related to f. T=1/f Unit sec.

__________- The _________ travelled by a wave in a given amount of ________, __________ONLY upon the __________. Ex. 100 meters in one second = 100 m/s. Speed= ______/_______ What is the speed of a wave that travels 50 m in 5 secs?

Wave Speed The Wave Speedpeed ttravels – ie: distance a crest or compression goes in a certain amount of time Depends on the medium the wave’s traveling through – Due to density variations – > dense = faster sound slower light – < dense = faster light slower sound Calculating wave speed: Wave speed (v) Wavelength (Λ) Frequency (f) v = Λ X f Unit = meters/sec (m/s)

Wave speed (v) Wavelength (Λ) Frequency ( f ) Speed= ____ x f Wavelength = ____ / f Frequency = v / _____ What is the frequency of a wave that is 2 m long and going at 10 m/s?

Frequency _________ wavelength = _______ frequency Medium wavelength = medium frequency ________ wavelength = ________ frequency

Frequency Don’t confuse the frequency with the speed of a wave. Here’s an analogy:

Frequency If you were looking down on a freeway... And all of the vehicles were going exactly 60 miles per hour (the same speed)...

Frequency Small cars going 60 miles per hour

Frequency Bigger cars going 60 miles per hour

Frequency Really big vehicles going 60 miles per hour

Frequency Speed = 60 miles per hour Small cars = high frequency (6) Bus = low frequency (1)

Frequency Light speed = 186,000 miles per second Blue light waves = higher frequency Red light waves = lower frequency

9/16 p.24Bill Nye Waves IQ: Which of the following is the best representation of what probably happens to a sound wave travelling through the same medium over time if no more energy is added?

OQ: What is the speed of a wave that travels 50m in 100s?

9/16Waves Mini labs What is the frequency of the following wave if it happened over 2s? Calculate the speed of the wave using v= 20 m

Wave machine demo (start at 1:19) Wave machine demo

OQ: What was the source of energy for the waves you made today? What is the medium? a.The slinky b.The table c.Your hand d.The air

IQ: Yellow half sheet

OQ: Which of the following could NOT be used as evidence to prove that the medium itself does not move during the transfer of energy through a wave? (more than one answer possible) A.As a wave travels down a rope, the particles of the rope don’t get transferred down. B.Longer waves travel farther from their source than shorter waves. C. A piece of string tied to a slinky would not leave its place if a wave is created in the slinky. D. The soil does not get carried from 1 place to another during an earthquake.