3.4 Waves: What are waves?
Compare transverse and longitudinal waves, calculate wave quantities and use the electromagnetic spectrum and ultrasound.
How to study WJEC GCSE The Sciences
Move from a scientific model to a prediction or method, collect or interpret evidence, show quantitative working and finish with a conclusion whose limits match the data.
Core concepts
Concept 1
Classify waves by vibration direction and identify key properties.
Exam cue: Identify the unit, entered tier, supplied reference material, command word and relevant scientific enquiry skill.
Concept 2
Use wave speed, frequency and wavelength relationships.
Exam cue: State the propagation and vibration directions, then use consistent SI units in the wave equation.
Concept 3
Compare electromagnetic regions and explain ultrasound applications.
Exam cue: Use scientific terminology, show quantitative working with units, and connect conclusions to data and the stated model.
Concept 4
Official subtopics: 3.4.1 Longitudinal and transverse waves; 3.4.2 Wave properties; 3.4.3 The electromagnetic spectrum; 3.4.4 Ultrasound.
Concept 5
Scientific enquiry and mathematical skills apply in this topic; bold amplification is Higher Tier only.
Risk pitfalls and guardrails
Confusing amplitude with wavelength or ordering the spectrum inconsistently.
Guardrail: Do not import outgoing 3430QD content, another science route, a fixed required-practical list or unsupported tier and connection assumptions.
Recalling a fact without applying it to the observation, data, practical method or unfamiliar context.
Guardrail: Use the live secure pack: Task A may use groups of up to three; Task B is individual and highly controlled. Two enquiries are selected by the centre from three.
Importing content, required practicals, tier rules or paper structure from the outgoing WJEC or another awarding-body route.
Guardrail: Bold amplification is Higher-only. Units 1-6 may mix tiers, but Unit 7 is untiered.
Memory anchors
Transverse wave
Vibrations are perpendicular to the direction of energy transfer.
Longitudinal wave
Vibrations are parallel to the direction of energy transfer.
Frequency
Number of complete waves passing a point per second.
Wavelength
Distance between equivalent points on adjacent waves.
Ultrasound
Sound with frequency above the upper limit of human hearing.
Checkpoint rule
Do the check-up only after you can summarize each concept in one sentence and identify one dangerous pitfall from memory.
Knowledge Check (after reading)
Short check-up to confirm understanding of this module.
Check-up Questions
What do waves transfer from one place to another? Use vibration direction, frequency, wavelength and speed without changing the medium. Base the comparison on like-for-like evidence.
Which description defines a transverse wave? Use vibration direction, frequency, wavelength and speed without changing the medium. Account for the control condition before comparing results.
Answer all questions to submit.
Next step personalized recommendations
Continue learning
Move forward only after this module is stable.
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