What are waves? A wave is a temporary disturbance that transfers energy from place to place.
What carries waves? Many types of waves require a medium to travel. A medium is the material through which a wave travels. Some examples are air, water or rope. The waves do not carry the medium with them. It’s what they travel through. Waves that require a medium through which to travel are called mechanical waves.
What causes waves? Waves are generated when a source of energy forces the matter in a medium to vibrate. A vibration is a repeated back-and- forth or up-and-down motion.
Types of Waves Transverse Longitudinal
Transverse Waves Transverse waves are waves that move the medium at right angles to the direction in which the waves are traveling. EX// Electromagnetic
More about Transverse waves Transverse means “across”. The highest parts of the wave are called crests. The lowest parts of the waves are called troughs
Transverse waves have several parts to them… The crests are the ‘bumps’ at the top of the wave. The troughs are the ‘bumps’ on the bottom. The Normal is how the medium would be if there was no wave. (Solid line in the middle)
Longitudinal Waves Longitudinal waves move the particles of the medium parallel to the direction that the waves are traveling. Ex// Sound waves
More about Longitudinal Waves The parts where the waves are close together are called compressions. Rarefactions are the parts where the waves are spread out.
All waves share certain properties: Amplitude Wavelength Frequency Properties of Waves All waves share certain properties: Amplitude Wavelength Frequency
Wavelength Wavelength is the distance between two corresponding parts of a wave. Transverse waves – measure crest to crest or trough to trough.
Frequency The frequency of a wave is the number of complete waves that pass a given point in a certain amount of time. Transverse waves = # of crests that pass a given point in 1 second
Measuring Frequency Frequency is measured in units called hertz (Hz). A wave that occurs every second has a frequency of 1 Hz. Two waves that pass every second has a frequency of 2Hz.
Amplitude Amplitude is the maximum distance the particles of the medium carrying the wave move away from their rest positions.
Amplitude for Transverse waves The measure of distance from the resting point to a crest or trough.
Quick Check Identify the parts of the following wave: Wavelength Amplitude Crest Trough How often = Frequency
Electromagnetic Waves