An Introduction to Waves 3U Physics

What is a wave? A wave is a disturbance which carries energy from one location to another.

What is a wave? A wave is a disturbance which carries energy from one location to another. The material the disturbance travels through is the ? The movement of the disturbance is referred to as ?

What is a wave? A wave is a disturbance which carries energy from one location to another. The material the disturbance travels through is the medium. The movement of the disturbance is referred to as ?

What is a wave? A wave is a disturbance which carries energy from one location to another. The material the disturbance travels through is the medium. The movement of the disturbance is referred to as propagation.

2 Types of Waves A longitudinal wave is a wave in which the particles of the medium move in a direction parallel to the direction of propagation.

2 Types of Waves A longitudinal wave is a wave in which the particles of the medium move in a direction parallel to the direction of propagation.

2 Types of Waves A longitudinal wave is also called a pressure wave or a sound wave.

2 Types of Waves A longitudinal wave is also called a pressure wave or a sound wave. The regions of increased pressure/density are called ?. The regions of decreased pressure/density are called ?.

2 Types of Waves A longitudinal wave is also called a pressure wave or a sound wave. The regions of increased pressure/density are called compressions. The regions of decreased pressure/density are called ?.

2 Types of Waves A longitudinal wave is also called a pressure wave or a sound wave. The regions of increased pressure/density are called compressions. The regions of decreased pressure/density are called rarefactions.

2 Types of Waves A transverse wave is a wave in which the particles of the medium move in a direction perpendicular to the direction of propagation. Although sound waves are not transverse waves, we often represent them as transverse waves because transverse waves are easier to draw.

2 Types of Waves The vertical axis represents not displacement but pressure.

Snapshot of a Transverse Wave The dashed line represents the equilibrium position of the particles.

Snapshot of a Transverse Wave The positions of maximum displacement are referred to as crests (positive displacement) and troughs (negative). The maximum displacement is the amplitude.

Snapshot of a Transverse Wave The positions of maximum displacement are referred to as crests (positive displacement) and troughs (negative). The maximum displacement is the amplitude. Amplitude = Energy

Snapshot of a Transverse Wave The distance between one crest and the next crest (or one trough and the next trough) is the wavelength, represented by .

Snapshot of a Transverse Wave The time it takes one complete wavelength to pass a single point is the

Snapshot of a Transverse Wave The time it takes one complete wavelength to pass a single point is the period, represented by T.

Snapshot of a Transverse Wave The number of complete wavelengths that pass a single point in one second is the frequency, represented by f.

Frequency Frequency is measured in units of 1/s or s-1 or Hertz (Hz). “I do not think that the wireless waves I have discovered will have any practical application.”

Wave Speed The speed of a wave is therefore:

Wave Speed The speed of a wave is therefore:

Wave Speed The speed of a wave is therefore:

Wave Speed The speed of a wave is therefore: The speed of a sound wave in air at room temperature (20oC) is 344 m/s.

Sound Wave Example Calculate the wavelength of the sound wave produced by a 125 Hz tuning fork in air at 20oC.

Sound Wave Example Calculate the wavelength of the sound wave produced by a 125 Hz tuning fork in air at 20oC.

Sound Wave Example Calculate the wavelength of the sound wave produced by a 125 Hz tuning fork in air at 20oC.

More Practice Inquiry Activity: Slinky Waves Homework: Textbook reading/questions (see handouts)