2 What is a mechanical wave? A disturbance in matter that carries energy from one place to another.Require a material to pass through called a medium.A medium can be a solid, liquid, or a gas.3 types of mechanical waves.1. Transverse waves2. Longitudinal waves3. Surface waves
3 Transverse wavesCause the medium to vibrate at right angles to the direction of wave motion.Wave motion Slinky motion
4 Parts of a transverse wave wavelengthRest positionnodewavelength
5 Trough – the bottom of a wave. Crest – the top of a wave.Trough – the bottom of a wave.Wavelength – the distance from crest to crest or trough to trough.Node – where the wave intersects the rest position.Amplitude – distance from the rest position to a crest or trough – measures energy.Frequency – how many times the wave cycles in a given time period.Usually measured in Hertz (Hz) – cycles per secondLow frequencyHigh frequency
6 Wavelength and Frequency These 2 are relatedAs one increases, the other decreases.Low frequency, large wavelengthHigh frequency, small wavelength
7 Longitudinal Waves Compression waves Move the medium the same direction as the wave.Made from compressions and rarefactionsWave motionSlinky motion
8 Surface Waves Travel along the surface separating 2 media. Ocean waves travel between water and airHave characteristics of both longitudinal and transverse waves.Transverse part causes up and down motion.Longitudinal part causes back and forth motion.
9 Wave Speed Speed = frequency X wavelength n f l n = speed (m/s) f = frequency (Hz)l = wavelength (m)