What is a wave?

Rhythmic disturbances that carry energy without carrying matter

Types of Waves

• Mechanical Waves

• Electromagnetic Waves

Mechanical Waves

• need matter (or medium) to transfer energy

• A medium is the substance through which a wave can travel. 

• Examples of MEDIUMS: Air; water; particles; strings; solids; liquids; gases

Electromagnetic Waves

• DO NOT NEED matter (or medium) to transfer energy

• •They do not need a medium, but they can go through matter (medium), such as air, water, and glass

Examples of Mechanical Waves

• Sound Waves

• Ocean Waves

• Ripples in Water

• Earthquakes

• Wave of people at a sporting event

Transverse Waves

• Energy causes the matter in the medium to move up and down or back and forth at right angles to the direction the wave travels.

• The crest is the highest point on a wave. 

• The trough is the valley between two waves, is the lowest point.

Parts of a Transverse Wave

• The wavelength is the horizontal distance, either between the crests or troughs of two consecutive waves. 

  
  

• The amplitude is the peak (greatest) value (either positive or negative) of a wave. The distance from the undisturbed level to the trough or crest.

  
  

Longitudinal Waves

• •A mechanical wave in which matter in the medium moves forward and backward along the same direction that the wave travels.

• Example: Sound Waves

• Also called "compressional" waves

Parts of a Longitudinal Wave

• The compression is the part of the compressional wave where the particles are crowded together

• The rarefaction is the part of the compressional wave where the particles are spread apart. 

• The wavelength is the distance from compression to compression or rarefaction to rarefaction in a compressional wave. 

  
  

Electromagnetic Waves

• Waves that DO NOT NEED matter

  (medium) to transfer energy

  
  

• Electromagnetic waves are considered transverse waves because they have similar characteristics; therefore, they have the same parts.

  
  

Examples of Electromagnetic Waves

• gamma rays

• TV

• radio waves

• x-rays

• microwaves

• visible light

• infrared rays