Wave Interactions What interactions can waves undergo Reflection

Wave Interactions

What interactions can waves undergo?

Reflection �Reflection- happens when a wave bounces after hitting a barrier.

Reflection �All waves can be reflected.

Refraction �Refraction – is the change in direction of a wave when it changes speed as it travels from one material(medium) to another. refraction occurs when a wave changes speed. Light waves change direction when they slow down as they pass from air to water.

Diffraction �The bending of waves around a barrier or through an opening is known as diffraction.

Diffraction nosey Sound wavelengths are MUCH longer than light wavelengths (measured in nanometers). This is why you can hear someone talking in another room with an open door, even though you can’t see them.

Interference happens when waves overlap q Constructive: amplitude increases q Destructive: amplitude decreases

Interference

Resonance – vibration produced in one object that is caused by the vibration produced in another

**Finish filling in this chart** • • _________ properties can undergo • • ____ reflection ____ interference WAVES types examples • • • x-rays radio waves infrared radiation microwaves visible light examples do _____need a _____ are always need a _____ can be either • • • sound water ropes earthquakes tsunami waves

**CHECK YOUR ANSWERS** • • amplitude wave length frequency wave speed properties can undergo • • • refraction reflection diffraction Interference resonance WAVES types examples • • • x-rays radio waves infrared radiation microwaves visible light Electromagnetic Waves do NOT need a medium are always Transverse Mechanical Waves need a medium can be either examples • • • Longitudinal sound water ropes earthquakes tsunami waves

Seismic Waves

How are waves in Earthquakes like other waves?

Seismic Waves • Seismic waves move through the ground during an earthquake.

Seismic Waves Primary Waves are longitudinal (compressional) waves Secondary Waves are transverse waves • Some of these waves are longitudinal (compressional), and others are transverse.

Seismic Waves The seismic waves that cause most damage to buildings are a kind of rolling waves. These rolling waves are surface waves and are a combination of longitudinal and transverse waves.

Seismic Waves: Surface Waves Love Wave Rayleigh Wave

SEISMIC WAVES (to tune of Silver Bells) Feel a rumble, then a grumble What is happ’ning you say Underground there’s a feeling of earthquake Building-swaying, terror-making Falling bricks block your way And with each faithful tremor you think … Seismic waves, seismic waves They’re why the building is swaying After shocks, faulted rocks We’ll just rebuild it next year P and S waves, and the L waves From the focus they race Through the earth they can travel a distance P are faster, L are “laster” Liquid S leaves no trace And among on the rubble you fear … Seismic waves, seismic waves They’re why the driveway is cracking Rictcher scale, start to wail We’ll just repave it next year S 2 ? H g Y v= m /w o e. c ub t u w w //w 8 : tp kp t h Q E 7 . yo ch t a