What do these images have in common?

They are all WAVES!!! Time for Surfing!!! Why Waves Are Wonderful!!

 Imagine that your family has just returned home from a day at the beach. You had fun playing in the ocean under a hot sun. You put some cold pizza in the microwave for dinner, and you turn on the radio. Just then, the phone rings. It's your friend calling to ask about homework.

Unit 4 The Nature of Waves

 What are the major parts of a standard wave?  What are the different types of wave?  How do waves travel?  How are waves pertinent to my everyday life? Unit Goals

 A TRANSFER OF ENERGY through matter OR empty space  A MEDIUM is any material that a wave travels through. A medium can be a solid, liquid or gas. What Is A Wave?

 As a wave is traveling it is moving everything else in its path (waves working).  Anything floating on the surface of water is being worked by waves.  Example: Boats and ducks bob up and down on a waves shows that waves are transferring energy. Waves and Work

Can anyone describe the energy transfers that are occurring here? Moving Object Medium=Water Waves show transfer of energy from propeller through water

 A MEDIUM is any material that a wave travels through. A medium can be a solid, liquid or gas.  A medium can be a solid, liquid or gas.  The plural ( more than one) of medium is media Medium

 Mechanical  Electromagnetic There are Two Major Categories of Waves

 Need a medium to transfer energy! CANNOT travel through empty space  OCEAN WAVES AND SOUND WAVES ARE EXAMPLES Mechanical Waves

 Do not need a medium, CAN travel through empty space!  Electromagnetic waves (light waves, microwaves, x- rays) can travel through empty space Electromagnetic Waves

 There are three type of waves: -Transverse -Longitudinal -Surface/Water Types of Waves

 Transverse waves- are particles that move in an up –and- down motion. The particles in a transverse wave move across or perpendicular  The highest point on a transverse wave is called a Crest  The lowest point on a transverse wave is called a Trough Transverse Wave

 Longitudinal waves- particles of the medium vibrate back and forth along the path the wave moves.  Compression- the part of the longitudinal wave where the particles are crowded together  Rarefactions- where the particles are spread apart Longitudinal Waves

 Use your JUMP ROPE! To demonstrate a transverse wave: – Work with a partner – One of you move your end of the Rope back and forth (left and right, like a snake crawling), perpendicular to its stretched length. – The other student must hold his or her end of the Rope still – A series of transverse waves will be generated and will travel through a medium (Rope) Time to Practice!

Longitudinal Waves

 A sound wave is a longitudinal wave.  Sound waves travel by compressions and rarefactions of air particles Longitudinal Waves

 Use your Slinky to demonstrate a longitudinal wave: – Work with a partner – Stretch it out along the table – One of you grasp and draw several coils of a stretched Slinky toward yourself – Release the coils – The other student must hold his or her end of the Slinky still – A longitudinal wave pulse will be generated and travel down the length of the Slinky (Medium) Time to Practice!

 Combination waves- when a transverse wave and a longitudinal wave combine to form a surface wave.  Surface waves look like transverse waves, but the particles of the medium move in circles rather than up and down. Surface and Combination Waves

Properties of Waves

A. Rest Position: The center of a wave; point where particles stay without disturbance

1) AMPLITUDE 2) WAVELENGTH 3) FREQUENCY 4) SPEED THERE ARE 4 BASIC PROPERTIES OF WAVES!

Amplitude: The farthest distance the particles of a wave’s medium vibrate from their rest position; BIGGER=more energy

Wavelength: The length of the wave; crest to crest or trough to trough; compression to compression; rarefaction to rarefaction; smaller=more energy

Frequency: The number of waves produced in a given amount of time

1)In you engineering notebook 2) On the top half of the page, use some yarn to make a transverse wave. Neatly label the crest and the trough! 3) On the bottom half of the page, make a longitudinal wave. Neatly label the compression and the rarefactions Lets Make a Model!

 Speed at which a wave travels  Wavelength x frequency = wave speed Wave Speed

 Wavelength – 10 cmFrequency – 20 Hz  Wavelength – 2 cmFrequency 4000 Hz  A wave has a wavelength of 5 cm. Its frequency is 700 Hz. What is its wave speed? Let’s Try!

Let’s Review!!!!

 Crest to Crest  Trough to Trough  Make a LARGE wavelength!  Make a small wavelength!  Which had more energy???? Wavelength

 Small amplitude and big wavelength  HUGE amplitude and small wavelength  Which would sound louder?  Bigger amplitude – more energy!! Amplitude

Amplitude and Wavelength to our EARS

 Number of waves produced in a given amount of time  Measured in HERTZ (waves/second)  Higher frequency = more energy  PITCH related to frequency!  Higher pitch – higher frequency – more energy! Frequency

Draw a transverse wave with 5 full waves. Identify: *Amplitude *Wavelength *Crest *Trough Exit Ticket – On ENB Rest Position