# Unit 2: Oscillations and Waves

Students will appreciate the range of orders of magnitudes handled by Physicists. They will learn the meaning of significant digits, and the importance of order of magnitude. They will practise making order-of-magnitude estimations. Students will learn that a quantity is a number multiplied by a unit, and they will learn how the S.I. units are structured. They will learn about the central role of uncertainty in experimental science, and they will practise processing uncertainties in both arithmetical and graphical contexts. They will distinguish scalar and vector quantities, and review and expand their skills in handling vector quantities.

#### Essential idea

Motion may be described and analysed by the use of graphs and equations.

## Learning Targets

#### SMEO

Unique Individuals: Students will come to appreciate that the characteristics of a physical system are determined not just by its component parts, but by the motions imparted to them, and the forces that act among them. From the notorious three-body problem in gravitation, which is not susceptible to analytical solution, they will learn that law-abiding systems can nevertheless manifest chaotic behaviour. Apply this to a system as complicated as a human being: there is no better way to understand why each individual must be – simply has to be – unique.

• Simple harmonic oscillations
• Time period, frequency, amplitude, displacement and phase difference
• Conditions for simple harmonic motion
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.

Understandings:
• Travelling waves
• Wavelength, frequency, period and wave speed
• Transverse and longitudinal waves
• The nature of electromagnetic waves
• The nature of sound waves
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

Understandings:
• Wavefronts and rays
• Amplitude and intensity
• Superposition
• Polarization
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.

Understandings:
• Reflection and refraction
• Snell’s law, critical angle and total internal reflection
• Diffraction through a single-slit and around objects
• Interference patterns
• Double-slit interference
• Path difference
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

The detailed curriculum can be consulted here.