Chapter 14 Waves

I. What’s in a wave? A.A WAVE is a repeating disturbance or movement that transfers energy through matter or space. 1.Waves transfer energy from one place to another. B. Waves don’t move the matter they travel in, they just transfer energy. C. A wave will travel only as long as it has energy to carry.

II. Types of Waves A.The matter a wave travels through is called a medium. B. Some types of waves do not travel through any type of medium. 1.Waves that travel through a medium are called mechanical waves. 2. Two types of mechanical waves: Transverse waves Compression waves

C. Transverse wave C. Transverse wave - matter moves back and forth at right angles to the direction that the wave travels.

Compression waves D. Compression waves – matter moves back and forth in the same direction that the wave travels. 1.Sound waves are Compression waves.Sound waves are Compression waves. 2. Air molecules vibrate and compress causing a wave.

III. Parts of a transverse wave

NameDefinitionSymbolMeasured In VelocitySpeed of a wavevm/s Wavelength Distance between one crest to the next crest meters Frequency # of waves that pass a point in one second HzHertz Period Time for one wavelength of a wave to pass a point  Seconds

What is the difference between Period and Frequency? Example: Suppose you are at a railroad crossing waiting for a train to pass. All of the cars are the same length. 120 cars pass in 5 minutes (300 seconds). 1 st Calculate the Period: Period (T) = # of seconds it takes for one car to pass T = seconds/car T = 300 seconds/120 cars = 2.5 seconds for 1 car to pass

What is the difference between Period and Frequency? Example: Suppose you are at a railroad crossing waiting for a train to pass. All of the cars are the same length. 120 cars pass in 5 minutes (300 seconds). 1 st Calculate the Frequency: Frequency (F) = # of cars that pass in one second F = cars/second F = 120 cars/300 seconds = 0.4 cars pass in one second

The string of a piano that produces the note middle C vibrates with a frequency of 264 Hz. If the sound waves produced by this string have a wavelength of 1.30m, what is the speed? Given: frequency = wavelength  = velocity = ? 264 Hz 1.30 m v f v = 264 Hz x 1.30 m v = m/s