4. Waves

4.1 – Oscillations

Nature of science:

The concept of momentum and the principle of momentum conservation can be used to analyse and predict the outcome of a wide range of physical interactions, from macroscopic motion to microscopic collisions.

Understandings:

Applications and skills:

Qualitatively describing the energy changes taking place during one cycle of an oscillation
Sketching and interpreting graphs of simple harmonic motion examples

Nature of science:

Patterns, trends and discrepancies: Scientists have discovered common features of wave motion through careful observations of the natural world, looking for patterns, trends and discrepancies and asking further questions based on these findings.

Understandings:

Applications and skills:

Explaining the motion of particles of a medium when a wave passes through it for both transverse and longitudinal cases
Sketching and interpreting displacement–distance graphs and displacement–time graphs for transverse and longitudinal waves
Solving problems involving wave speed, frequency and wavelength
Investigating the speed of sound experimentally

Nature of science:

Imagination: It is speculated that polarization had been utilized by the Vikings through their use of Iceland Spar over 1300 years ago for navigation (prior to the introduction of the magnetic compass). Scientists across Europe in the 17th–19th centuries continued to contribute to wave theory by building on the theories and models proposed as our understanding developed.

Understandings:

Applications and skills:

Sketching and interpreting diagrams involving wavefronts and rays
Solving problems involving amplitude, intensity and the inverse square law
Sketching and interpreting the superposition of pulses and waves
Describing methods of polarization
Sketching and interpreting diagrams illustrating polarized, reflected and transmitted beams
Solving problems involving Malus’s law

Nature of science:

Competing theories: The conflicting work of Huygens and Newton on their theories of light and the related debate between Fresnel, Arago and Poisson are demonstrations of two theories that were valid yet flawed and incomplete. This is an historical example of the progress of science that led to the acceptance of the duality of the nature of light.

Understandings:

Applications and skills:

Sketching and interpreting incident, reflected and transmitted waves at boundaries between media
Solving problems involving reflection at a plane interface
Solving problems involving Snell’s law, critical angle and total internal reflection
Determining refractive index experimentally
Qualitatively describing the diffraction pattern formed when plane waves are incident normally on a single-slit
Quantitatively describing double-slit interference intensity patterns

Nature of science:

Common reasoning process: From the time of Pythagoras onwards the connections between the formation of standing waves on strings and in pipes have been modelled mathematically and linked to the observations of the oscillating systems. In the case of sound in air and light, the system can be visualized in order to recognize the underlying processes occurring in the standing waves.

Understandings:

Applications and skills:

Describing the nature and formation of standing waves in terms of superposition
Distinguishing between standing and travelling waves
Observing, sketching and interpreting standing wave patterns in strings and pipes
Solving problems involving the frequency of a harmonic, length of the standing wave and the speed of the wave

Last updated 2 years ago