What are waves?
Wave Definition: A disturbance that transfers energy from place to place. What carries waves… it depends on the wave type. Transverse Wave Longitudinal Wave Surface Wave
What causes waves? Waves are created when a source of energy causes a medium to vibrate. A vibration is a repeated back and forth or up and down motion.
The difference between waves #1: Whether or not there is a medium for the wave to travel through and #2: The direction which particles of the medium vibrate compared with the direction in which the waves move.
What is a Medium? Definition: A medium is the material through which a wave travels. A medium can be a gas, liquid, or solid. Example of wave that requires a medium: sound waves Waves that require a medium are also called Mechanical Waves
Not all waves require a medium to travel. Example of wave that does not require a medium: Electromagnetic Waves (EM) These are light energy waves!
Types of waves: Waves are classified according to how they move.
Wave 1: Transverse Wave AKA: Light waves
Transverse wave Definition: Waves that move the medium at right angles to the direction in which the waves are traveling.
Transverse wave Transverse means moving across. The highest parts are called crests the lowest parts are called troughs.
Transverse Wave: Light Energy
Light Energy: The Electromagnetic Spectrum Remember, light energy is energy produced by the vibration of electrically charged particles. Why can electrically charged particles move without a medium? Because they are electrically charged!
How Light Energy Works Step 1: A vibrating electrical particle = an electrical field. Step 2: The electrical field vibrating causes a magnetic field. Step 3: Electric Field + magnetic field = EM wave Radiation: Transfer of energy as EM waves
How Light Energy Works Electric Field Vibration Magnetic Field Vibration Direction of wave
Wave 2: Longitudinal Wave AKA: Compression Wave
Longitudinal Wave Definition: Wave in which the particles of the medium vibrate in the same direction as the wave travels. Example: Sound Waves
What are sound waves? Definition: Waves produced by the energy of vibrating objects into the air.
Longitudinal Wave
Longitudinal wave The parts where the coils are close together are called compressions, the parts where the coils are spread out are called rarefactions.
Hearing Loss Most common type of hearing loss is called tinnitus. Caused by long term exposure to loud sounds. Nerve endings and hairs in cochlea are damaged so they do not grow back.
What’s the point? Turn your IPods down unless you want a hearing aid latter in life!
Wave 3: Surface Waves AKA: Rayleigh Waves
Surface Waves Surface waves are a combination of transverse and longitudinal waves. The particles move in circles rather than up and down
Surface Waves Mechanical Waves: Like ocean waves or Rayleigh waves- seismic waves
Draw Transverse wave and label: crest & trough