Waves-Chapter 4

What’s a wave? Wave: a rhythmic disturbance that transfers energy through matter or space Two general types of waves: Mechanical waves Electromagnetic waves

Transverse wave

Transverse Waves Crest: highest point of a transverse wave Trough: lowest point of a transverse wave Amplitude: the amount of energy carried by a wave; corresponds to the height of a transverse wave Wavelength: the distance between two identical points on a wave

Sound wave generated by a tuning fork        Sound wave generated by a tuning fork            Longitudinal Waves Before the waves are made the particles are same distance apart. While waves moves through the medium the particles compress together, then they spread further apart (stretched areas)- rarefaction.

Longitudinal/Compressional Waves Rarefaction: expanded portion of the wave; particles are spread apart Compression: compressed (squeezed) portion of the wave; particles are pushed together Wavelength: the distance between two identical points on a wave Amplitude: the amount of energy carried by a wave; corresponds to the amount of compression in a longitudinal wave

Vibrations and Mechanical Waves One wave per vibration. Vibrations create waves. Vibration stops- waves keep moving. https://www.youtube.com/watch?v=FA5_5oXeQhU

Types of Mechanical Waves Sound Water Seismic

Mechanical Waves Require matter to travel through The matter the mechanical wave travels through is called a MEDIUM Examples of a medium that a mechanical wave can travel through: sound waves, earthquake waves, water waves Can be transverse or longitudinal Transverse Wave Longitudinal Wave

Sound Waves water Waves Seismic Waves Longitudinal waves (travel in solid, liquids and gases) Made of series of compressions and rarefactions Sound is produced when something vibrates. The vibrating body causes the medium (water, air, etc.) around it to vibrate.  Combination of transverse and longitudinal waves  Wind produces by pushing on the surface of water Waves in the Earth, cause earthquakes Both longitudinal and transverse. Movement along the Earth’s upper layers along a fault. Produces seismic waves

water Waves Sound Waves Seismic Waves

Mechanical Waves Two types of mechanical waves: Transverse : matter moves in the medium at right angles to the direction that the wave is travelling Examples: water waves, S-type earthquake waves Longitudinal: vibration is parallel to the direction of motion of the wave; back and forth motion; also called compressional waves Examples: sound waves, P-type earthquake waves

Electromagnetic Waves Do not require a medium through which to travel (means they can travel through a vacuum such as space) Examples: radio waves, microwaves, infrared waves (heat), light waves, UV rays, X-rays, gamma rays Are transverse waves

1 2 3 All electromagnetic waves travel at the same speed. Their speed is the speed of light = 300,000,000 m/s 2 That’s 186,000 miles/second!!!!!! 3

Amplitude- amount of energy carried by a wave Low Amplitude Medium Amplitude High Amplitude

Wavelength- distance between two identical points on a wave Short Wavelength Long Wavelength

Relationship between amplitude, wavelength, frequency, and energy HIGH AMPLITUDE = HIGH ENERGY LOW AMPLITUDE = LOW ENERGY LONG WAVELENGTH = LOW FREQUENCY = LOW ENERGY SHORT WAVELENGTH = HIGH FREQUENCY = HIGH ENERGY

Wave Interactions Reflected by matter Transfer to matter Pass through matter