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CP Sci 9- 1st Sem.

Gen Chem - 1st Sem.

Types of Waves:

Objectives:

    1.    Describe factors that affect the speed of waves.

    2.    Distinguish between transverse and longitudinal waves.

Key Terms:

    Transverse Wave    Longitudinal Wave

Web Resources:

 

Notes:

Waves and Energy:

A wave is a disturbance that transfers energy through matter or space.

Waves travel through a medium:

    A medium is any substance or region through which a wave is transmitted.

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Solid, liquid, or gas

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Transfers energy only without any net movement

The speed of a wave is dependant on four factors: wavelength, frequency, medium, and temperature.  Wave speed is calculated by multiplying the wavelength times the frequency (speed = l * f).  Certain conditions make the following calculations easy.

bulletspeed is constant in a given medium.
bulletsince speed is constant within the same medium, a high frequency has a short wavelength and vice-a-versa

As waves travel through a medium two properties affect wave speed

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Density- the higher the density the slower the wave

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Elasticity - waves travel faster through materials that are more elastic

Temperature:

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The speed of waves increase as temperature increases.  This is due to the increased kinetic energy of the air molecules and the decrease in density.

 

Types of Waves:

Transverse:

bulletThe motion of the transverse wave is at a right angle to the motion of the medium
bulletThere is no net displacement of the medium
bulletEvery transverse wave has a crest & trough
bulletlight, water, and guitar strings are all examples of transverse waves

example:    Water wave is up & down but motion is forward

Crest

Trough

           

 

 

Longitudinal Waves:

The motion of the wave is in the direction of the motion of the medium (parallel)  These types of waves are also known as compression waves.

bulletThe motion of the compression wave is parallel to the motion of the medium
bulletThere is no net displacement of the medium
bullet There are no crests and troughs but there are compressions and rarefactions
bullet

a compression is a space in a medium where the molecules are crowded together

bullet

A rarefaction is the space, in the medium, which there are fewer molecules.

bulletAir molecules behave in this manner sound

(capa6.phy.ohiou.edu/ psc105/gif/f3a.gif)

 

 

 

 

 

 

 

 

Last modified: September 05, 2004