Waves
Types of Waves
- Transverse waves are waves in which the vibrations are at right angles to the direction of travel. Examples include light and other electromagnetic waves and waves on strings.
- Longitudinal waves are waves in which the vibrations are in the same direction as the wave is traveling. Complete understanding of sound waves requires knowledge of these.
Wave Properties
- Discuss wavefronts and rays to represent waves diagrammatically.
- Wave amplitude: the maximum displacement of a point on a wave from its undisturbed position.
- Wave wavelength: the shortest distance between two points on a wave where the wave pattern is repeated.
- Wave frequency: The number of waves produced by a source each second. It is also the number of waves that pass a certain point every second.
- Wave speed: the speed at which energy is transferred (or the wave moves) through the medium.
- Wave period: the time taken for one complete wave to pass a given point, reciprocal of wave frequency.
Wave Behaviours
- Reflection: the bouncing back of a wave after hitting a boundary.
- Refraction: the bending of a wave as it enters a medium where its speed changes.
- Diffraction: the spreading of waves when they pass through a gap or around obstacles.
- Interference: the superposition of two or more waves resulting in a new wave pattern.
Electromagnetic Spectrum
- Recognise radio, microwave, infrared, visible light, ultraviolet, x-ray, and gamma rays in the electromagnetic spectrum.
- Consider the waves’ different characteristics, including their different wavelengths, frequencies, and uses.
Sound Waves, their Characteristics and Uses
- Sound waves are longitudinal waves and need to travel through a solid, liquid or gas.
- The speed of sound is different in different media.
- The frequency of a sound determines its pitch, and the amplitude determines its volume.
- Echoes can be used for sonar and ultrasound scanning.
Seismic Waves and the Earth’s Structure
- The Earth’s crust generates seismic waves. There are two distinct types: S-waves (secondary) and P-waves (primary).
- Seismic waves are used to evidence the Earth’s composition and structure, providing information about the Earth’s internal layers.