WAVE STRUCTURE AND IT'S BEHAVIOR

BEHAVIOR:

  The behavior of waves traveling along a rope from a more dense medium to a less dense medium (and vice versa) was discussed. The wave doesn't juststop when it reaches the end of the medium. Rather, a wave will undergo certain behaviors when it encounters the end of the medium. Specifically, there will be some reflection off the boundary and some transmission into the new medium. 

• REFLECTION-Bouncing back of wave (the angle of incidence = the angle of reflection)

• REFRACTION- waves involves a change in the direction of waves as they pass from one medium to another. Refraction, or the bending of the path of the waves, is accompanied by a change in speed and wavelength of the waves.

• DIFFRACTION-change in direction of waves as they pass through an opening or around a barrier in their path. Water waves have the ability to travel around corners, around obstacles and through openings.

Interference of Waves

     What happens when two waves meet while they travel through the same medium? What effect will the meeting of the waves have upon the appearance of the medium? Will the two waves bounce off each other upon meeting (much like two billiard balls would) or will the two waves pass through each other? These questions involving the meeting of two or more waves along the same medium pertain to the topic of wave interference.

      Wave interference is the phenomenon that occurs when two waves meet while traveling along the same medium. The interference of waves causes the medium to take on a shape that results from the net effect of the two individual waves upon the particles of the medium. To begin our exploration of wave interference, consider two pulses of the same amplitude traveling in different directions along the same medium.

This type of interference is sometimes called constructive interference. Constructive interference is a type of interference that occurs at any location along the medium where the two interfering waves have a displacement in the same direction.

In the diagram above, the interfering pulses have the same maximum displacement but in opposite directions. The result is that the two pulses completely destroy each other when they are completely overlapped. At the instant of complete overlap, there is no resulting displacement of the particles of the medium. This "destruction" is not a permanent condition. In fact, to say that the two waves destroy each other can be partially misleading. When it is said that the two pulses destroy each other, what is meant is that when overlapped, the effect of one of the pulses on the displacement of a given particle of the medium is destroyed or canceled by the effect of the other pulse.Destructive interference is a type of interference that occurs at any location along the medium where the two interfering waves have a displacement in the opposite direction.

Applications of waves in your everyday life

For Waves

Waves are everywhere. Most of the information that we receive comes to us in the form of waves. You rely on waves to bring you music and TV. You can cook with waves, talk to others and see things all because of waves. Waves transfer energy in different forms, some are very useful, while others can be deadly.

A Tsunamis or tidal wave is a very large water wave that has been produced by some kind of seismic phenomona. These waves can move at speeds of 500 km/h and have a period of 60 minutes. They can move across the ocean very quickly and cause incrediable damage to coastal regions.

Animals use wave motion to propel themselves through there surroundings. Eels and snakes use transverse body waves to push against the water or ground to help them move. Earth worms however, use longitudinal waves for propulsion. Others, like certain one-celled animals use flagella in a whiplike wave motion to move about their world.

Shock waves created out by a lighting may cause a sonic boom. Sonic booms can also be produced by aircraft flying at speeds greater than the speed of sound in air. Because of this the Concord aircraft has been banned from flying over inland portions of the United States.

http://www.lcse.umn.edu/specs/labs/waves/apps_to_everday.html

This shows a wave with the Group velocity and Phase velocity going in different directions

 Frequency dispersion of surface gravity waves on deep water. The red dot moves with the phase velocity, and the green dots propagate with the group velocity. In this deep-water case, the phase velocity is twice the group velocity. The red dot overtakes two green dots, when moving from the left to the right of the figure.

http://en.wikipedia.org/wiki/Wave

2 Types of waves according to direction

A wave can be transverse or longitudinal  depending on the direction of its oscillation/vibration.

• TRANSVERSE- occur when a disturbance creates oscillations perpendicular (at right angles) to the propagation (the direction of energy transfer)

• LONGIUDINAL- occur when the oscillations are parallel to the direction of propagation

> While mechanical waves can be both transverse and longitudinal, all electromagnetic waves are transverse.

○There are two main types of waves

• MECHANICAL WAVES

               -propagate through a medium, and the substance of this medium is deformed.

• ELECTROMAGNETIC WAVES

       -do not require a medium. Instead, they consist of periodic oscillations of electrical and magnetic fields generated by charged particles, and can therefore travel through a vacuum. 

A disturbance called WAVE

In physics, a wave is a disturbance or oscillation that travels through space and matter, accompanied by a transfer of energy.
The term wave is often intuitively understood as referring to a transport of spatial disturbances that are generally not accompanied by a motion of the medium occupying this space as a whole. In a wave, the energy of a vibration is moving away from the source in the form of a disturbance within the surrounding medium.

http://en.wikipedia.org/wiki/Wave