Waves, Sound, and Light
MYP Sciences Year 1 – Waves, Sound and Light
Light and sound are both waves — that's the whole trick to this unit. Once you accept that a rainbow, a guitar string and a dog whistle are all just 'energy moving through space in a repeating pattern', the exam questions stop being separate topics and become the same three ideas asked four different ways: what carries the wave, how do we describe it (amplitude, wavelength, frequency), and what happens when it hits something.
Overview: How This Chapter Fits Together
Every topic in this chapter is really the same question wearing different clothes: how does energy travel without matter travelling with it? Light and sound are both waves, but they differ in the one fact examiners test again and again — light is transverse and needs no medium; sound is longitudinal and always needs one. Everything else (colour, pitch, loudness, sonar, fibre optics) is just that one fact applied to a specific situation.
- Colour is what happens when your eye detects a narrow band of the electromagnetic spectrum, split apart or reflected selectively.
- Sound is what happens when a vibrating source disturbs a medium in a longitudinal pattern that your eardrum can pick up.
- Pitch and loudness are just the human interpretation of two wave properties — frequency and amplitude — nothing more mysterious than that.
- Technology (sonar, radar, fibre optics) is just people borrowing wave behaviour that already exists in nature and pointing it at a problem.
The shape of the chapter
Command terms that decide your mark in this unit
| Command term | What it demands | AO | Mark-earning move |
|---|---|---|---|
| List | Give a sequence of names/answers with no explanation. | Criterion A | Each correctly ordered item earns credit alone — writing reasons here earns nothing extra and wastes time. |
| Identify | Pick out and name one specific feature from data, a graph, or a diagram. | Criterion A | A bare correct name secures the mark — don't justify it unless the question also says 'and explain'. |
| Describe | Give a detailed account, including a trend or characteristic, not just a label. | Criterion A | Needs a full sentence with a pattern or direction (e.g. 'wavelength decreases') — a single word rarely gets full marks. |
| Compare | State how two things relate — similarities, differences, or a quantitative link. | Criterion A | Must mention BOTH items in the same sentence (e.g. 'red has a longer wavelength than violet') — two separate descriptions without a link loses the mark. |
| Explain | Give the reason or mechanism behind an observation — the 'why', not the 'what'. | Criterion A | Needs cause-and-effect reasoning; restating the observation without a mechanism scores zero. |
| Name | Give only the correct term or word. | Criterion A | Same as List but for a single answer — one word/phrase is expected and sufficient. |
Key point
Overview