Transverse Waves• In a transverse wave the particle

displacement is perpendicular to the direction of wave propagation. The animation below shows a one-dimensional transverse plane wave propagating from left to right. The particles do not move along with the wave; they simply oscillate up and down about their individual equilibrium positions as the wave passes by.

Transverse Wave Motion

Longitudinal Waves• In a longitudinal wave the particle

displacement is parallel to the direction of wave propagation. The animation at right shows a one-dimensional longitudinal plane wave propagating down a tube. The particles do not move down the tube with the wave; they simply oscillate back and forth about their individual equilibrium positions.

Longitudinal Wave Motion

•It is the combination of Transverse and Longitudinal Waves.

Water Waves• Water waves are an example of waves that

involve a combination of both longitudinal and transverse motions. As a wave travels through the waver, the particles travel in clockwise circles. The radius of the circles decreases as the depth into the water increases. The movie below shows a water wave travelling from left to right in a region where the depth of the water is greater than the wavelength of the waves.

Water Waves Motion

Rayleigh surface waves• Another example of waves with both

longitudinal and transverse motion may be found in solids as Rayleigh surface waves (named after John W. Strutt, 3rd Baron Rayleigh). The particles in a solid, through which a Rayleigh surface wave passes, move in elliptical paths, with the major axis of the ellipse perpendicular to the surface of the solid. As the depth into the solid increases the "width" of the elliptical path decreases.

• Rayleigh waves are different from water waves in one important way. In a water wave all particles travel in clockwise circles. However, in a Rayleigh surface wave, particles at the surface trace out a counter-clockwise ellipse, while particles at a depth of more than 1/5th of a wavelength trace out clockwiseellispes. The movie below shows a Rayleigh wave travelling from left to right along the surface of a solid. I have identified two particles in yellow to illustrate the counterclockwise-clockwise motion as a function of depth.

• The Rayleigh surface waves are the waves that cause the most damage during an earthquake. They travel with velocities slower than S waves, and arrive later, but with much greater amplitudes. These are also the waves that are most easily felt during an earthquake and involve both up-down and side-to-side motion.

Sound Waves

• Three characteristics are used to describe a sound wave. These are wavelength, frequency, and amplitude.

• Wavelength; this is the distance from the crest of one wave to the crest of the next.

• Frequency; this is the number of waves that pass a point in each second.

• Amplitude; this is the measure of the amount of energy in a sound wave.

Oscilloscope of the Sound Waves

Pitch• This is how high or low a sound seems.

A birdmakes a high pitch. Alion makes a low pitch.

• Sounds also are different in how loud and how soft they are.

• The more energy the sound wave has the louder the sound seems. The intensity of a sound is the amount of energy it has. You hear intensity as loudness.

• Remember the amplitude, or height of a sound wave is a measure of the amount of energy in the wave. so the greater the intensity of a sound, the greater the amplitude.

• Pitch and loudness are two ways that sounds are different. Another way is in quality.Some sounds are pleasant and some are a noise.

• Compare the two waves on the right.

• A pleasant sound has a regular wave pattern. The pattern is repeated over and over. But the waves of noise are irregular. They do not have a repeated pattern.