Wave Behavior

The change in direction of a wave when it strikes a boundary.

Diagrams from page 292 in journal. Draw them exactly as you see them.

Reflection

The manner in which a wave is reflected off a boundary is described as the law of reflection.

It states the incident angle is equal to the measurement of the reflected angle.

Law of Reflection

Specular reflection is mirror-like in nature. Diffuse reflection is when the wave is

reflected at many angles instead of just one. This is seen when a wave strikes a rough surface. This commonly occurs with light waves.

Draw in the diagram from page 293. An echo is another name for the reflected

wave.

Types of Reflection

The change in the direction of a wave when it passes from one medium to the next.

A medium is the material that a wave travels through.

Draw in the diagram from page 294. The light waves shining on the straw are

slowed down when they pass from the air into the water, making the straw appear broken.

Refraction

The medium that the waves are coming from and the medium that the waves are passing into determines how the waves will bend.

A medium is characterized by its index of refraction, which tells how speed of a wave will be affected while it is traveling in that medium.

It is a ratio of the speed of light in a vacuum compared to the speed of light in the medium.

Index of Refraction

When a wave passes through a medium with a higher index of refraction, the wave will slow down and bend toward the normal.

When it passes through a medium with a lower index, the wave will speed up and bend away from the normal.

Draw in diagram 8.2-5 into your journal. As seen in a prism, the different colors of white

light will bend at different angles.

Index of Refraction

This describes the bending of waves after striking the edge of an obstacle.

It is different than refraction because in refraction, the waves pass through the obstacle.

A detecting screen could be placed on the other side of the obstacle to find the diffraction pattern.

Diffraction enables sound to be heard around a corner.

Diffraction

Interference describes how two or more waves affect each other when they meet.

There are two types of interference: Constructive Interference Destructive Interference

Interference

States that when two or more waves combine, the amplitude of the resultant wave is equal to the algebraic sum of the amplitudes of the individual waves.

Principle of Superposition

When two or more waves with amplitudes in the same direction meet, they undergo constructive interference.

These waves are “constructive” to each other, creating a resulting wave with a larger amplitude.

You can find the amplitude of the resultant wave by adding the amplitudes of each of the individual waves together.

Constructive Interference

Constructive Interference

When two or more waves that have equal but opposite amplitudes meet, they undergo destructive interference.

They are “destructive” to each other, creating a resulting wave with zero amplitude.

Destructive Interference

Destructive Interference

Commonly seen in electromagnetic waves. Example: The cracking sound that can be

heard through the computer speakers when a cell phone is used nearby is the result of electromagnetic wave interference.

This is one reason why cell phones are not allowed in hospitals and on airplanes. It could cause serious issues with important communication and medical equipment.

Interference

The apparent change in frequency that comes from the motion of either the wave source or the observer.

It can be observed when a car drives by a person standing on the sidewalk. The frequency of the sound of the car seems to be higher as the car approaches and lower as the car pulls away.

Doppler Effect

Doppler Effect

Doppler Effect

Doppler Effect

Resonance