Earthquakes and Waves

Important characteristics of an oscillation

Frequency, amplitude, equilibrium position, displacement and damping

Equation to calculate frequency and/ or time period

T=1/f

Natural frequency (+recognise resonance situations)

It is the inherent frequency at which an object or system will vibrate/ossiculate if disturbed from its equilibrium.

Characteristics of waves

1. Wavelength: The distance between successive crests (or troughs) of a wave. It's the length of one complete wave cycle.

2. Frequency: The number of wave cycles that pass a given point per unit time (usually per second). It's measured in Hertz (Hz).

3. Amplitude: The maximum displacement of a point on a wave from its rest position. It determines the wave's intensity or energy.

4. Period: The time it takes for one complete wave cycle to pass a given point. It's the reciprocal of the frequency.

5. Speed: The speed at which a wave travels through a medium. It's determined by the type of wave and the medium it travels through

Types of waves and what they are

Longitudinal: A longitudinal wave is a wave where particles vibrate parallel to the direction of wave travel. An example is a sound wave.

Transverse: A transverse wave is a wave where particles vibrate perpendicular to the direction of wave travel. An example is waves on a string or water waves.

P-K and S-waves

P-K- Waves: P-waves, or primary waves, are a type of seismic wave that are the fastest and first to be detected during an earthquake. They are longitudinal waves, meaning the particles vibrate parallel to the direction of wave travel.

S-Waves: S-waves, or secondary waves, are a type of seismic wave that moves through the Earth during an earthquake. They are transverse waves, meaning the particles move perpendicular to the wave's direction of travel. S-waves can only travel through solids and are slower than P-waves, or primary waves.

The role of medium

The medium plays a crucial role in the transmission of waves, such as light, sound, or water waves. It is the substance or material through which the wave travels.

How a medium can impact wave speed

The medium essentially determines how and how fast the wave moves.

• For example, in the case of sound waves, the medium is usually air, water, or solids. Without a medium, sound cannot travel because it needs particles to propagate through.

• In the case of light waves, they can travel through a vacuum (like space) or transparent media such as glass or water. The properties of the medium, like density and elasticity, affect the speed and behavior of the wave.

Echolocation (+ application of v=s/t)

Echolocation is a method used by animals like bats and dolphins to locate objects by emitting sound waves and listening for the echoes that bounce back.

The formula v = s / t can be used to calculate the speed of sound in this process, where v is the speed, s is the distance traveled by the sound, and t is the time taken for the echo to return. This helps determine the distance to an object based on how long it takes for the echo to come back.