Light & Sound

What this lesson covers

Light & Sound is a 10-part Class 6 Science lesson. Each part makes one point and then hands over to the next, so it can be read in a sitting or picked up again at the part you stopped on. It defines the idea in plain words before using it, works through an example step by step, breaks the topic into its parts and compares them, shows where it is used outside the textbook, names the mistakes that cost marks in an exam, ends with a recap of what to remember.

How it begins

Light and sound both travel as waves and carry energy, which is why they behave similarly in some ways. But one difference matters enormously. Sound needs a material to travel through: air, water, metal. It cannot cross empty space. Light does not. It travels through a vacuum, which is why sunlight reaches Earth across empty space and why space is silent.

The 10 parts

1. Both are waves, but not the same kind
2. Comparing the two
3. Reflection and refraction
4. How far away is the storm?
5. Pitch and loudness
6. Why the sky is blue and sunsets are red
7. Light and sound at work
8. Where it usually goes wrong
9. What to remember
10. Watch one worked through