1. Waves in our world Part 1- Longitudinal and Transverse Waves and communication

2. What is this topic all about??? The World Communicates The Nature of Waves Properties of Sound Waves Reflection & Refraction Digital Communication & Data Storage Electromagnetic Waves General Types of Waves mechanical EM waves Transverse longitudinal Wave Measurements wavelength amplitude frequency period Wave Equation v = ƒ Graphing Waves Nature of Sound Waves Velocity Frequency & Pitch Amplitude & Loudness Principle of Superposition The Electromagnetic Spectrum Production & Detection of EMR Dangers of EMR Inverse Square Law EMR in Communication Refraction Snell’s Law Total internal reflection & critical angle Law of Reflection Reflection in communication Light & Mirrors

3. Waves in our World 1) A wave is a means of transferring energy and information from one point to another. http://alex.state.al.us/lesson_ view.php?id=24112

4. Waves in our World There is no transfer of matter between the two points. (means energy moves from one point to another. The particles in the wave do not move from one point to another).

5. Waves in our World 2) There are two types of waves: Transverse waves Longitudinal waves

6. Waves in our World 2) There are two types of waves: Transverse waves Longitudinal waves

7. Waves in our World How are Longitudinal waves different from transverse waves? 1) Longitudinal wave: is a wave whose particles oscillate in the same direction as the wave 2) Transverse wave: A wave whose particles oscillate perpendicular to the direction that the wave travels. travels.

8. 1) Longitudinal waves Longitudinal waves are waves where the vibrations of the particles are along the direction in which the wave travels. example: sound waves, ultrasound wave direction vibrations LONGITUDINAL WAVE longitudinal wave in slinky https://www.youtube.com/watch?v=y7qS6SyyrFU Waves in our World

9. 2) Transverse waves Transverse waves are waves where the direction of vibrations is at 90° to the direction in which the wave travels. example: water waves wave direction vibrations TRANSVERSE WAVE

10. 1. The wave model can be used to explain how current technologies transfer information describe waves as a transfer of energy disturbance that may occur in one, two or three dimensions, depending on the nature of the wave and the medium Waves carry energy from one place to another. All forms of wave motion transport energy, without transporting matter. This may occur in 1 dimension (pulses moving along a slinky spring), 2 dimensions (ripples spreading out on a surface of water) and 3 dimensions (light radiating out from a light bulb). identify that mechanical waves require a medium for propagation while electromagnetic waves do not Mechanical waves are those which require a medium to travel through. Sound waves need a substance such as air to travel through due to vibration of particles. Sound will not travel through a vacuum. “In space no one can hear you scream”. Electromagnetic (EM) waves do not need a medium. They can travel through a vacuum and in fact travel fastest through empty space. EM waves are self propagating. (They will be looked at in more detail in later topics). EM waves include light, radio waves and X-rays. define and apply the following terms to the wave model: medium, displacement, amplitude, period, compression, rarefaction, crest, trough, transverse waves, longitudinal waves, frequency, wavelength, velocity describe the relationship between particle motion and the direction of energy propagation in transverse and longitudinal waves There are two main types of mechanical waves; transverse and longitudinal (or compression).

11. In a longitudinal wave, the vibration of the particles of the medium is along the same direction as the motion of the wave. With a transverse wave, the particles vibrate up and down in a direction perpendicular to the motion of the wave itself. longitudinal wavetransverse wave Measuring Waves A transverse wave consists of a crest above the rest axis, and a trough below it. A longitudinal wave consists of compressions, where the particles are close together, and rarefactions, where the particles are spread apart. The amplitude (A) for both is the maximum displacement from the rest position. (Measured in metres) The wavelength ( ) is the distance between any two consecutive points. (Measured in metres)

12. The frequency (  ) of a wave is the number of waves that pass a particular point in one second. Units are Hertz (Hz). The period (T) of a wave is the time it takes for one complete wave to pass a point. Units are seconds (s) quantify the relationship between velocity, frequency and wavelength for a wave: v = ƒ solve problems and analyse information by applying the mathematical model of v = ƒ to a range of situations The wave equation indicates the speed of a wave in terms of wavelength and frequency. v = ƒ The units of velocity are ms -1 perform a first-hand investigation to observe and gather information about the transmission of waves in: – slinky springs – water surfaces – ropes or use appropriate computer simulations present diagrammatic information about transverse and longitudinal waves, direction of particle movement and the direction of propagation perform a first-hand investigation to gather information about the frequency and amplitude of waves using an oscilloscope or electronic data-logging equipment present and analyse information from displacement-time graphs for transverse wave motion plan, choose equipment for and perform a first-hand investigation to gather information to identify the relationship between the frequency and wavelength of a sound wave travelling at a constant velocity