Part 1 — Lessons (31)
1. How Plants Make Food
Green plants make their own food in a process called photosynthesis.
The leaves take in sunlight, water from the roots, and carbon dioxide from the air. They turn these into food (a sugar) and give off oxygen — the gas we breathe.
Why it matters: Plants are producers. They feed almost every living thing and keep our air fresh.
2. How Water Moves Around the Earth
The water cycle
Water is always moving between the sea, the sky and the land.
Evaporation: the Sun heats water in seas and rivers, turning it into invisible water vapour.Condensation: the vapour rises, cools and forms clouds.Precipitation: water falls back as rain. Then the cycle repeats.3. Electricity and Simple Circuits
Electricity can flow in a loop called a circuit. A simple circuit needs a battery, wires and a bulb.
The circuit must be complete (a full loop) for the bulb to light. If there is a break, the bulb goes off — that is what a switch does.
Materials that let electricity pass are conductors (metals); those that do not are insulators (plastic, rubber).
4. The Skeleton and Muscles
The skeleton is the frame of bones inside your body. It gives you shape, holds you up, and protects soft organs (the skull protects the brain; the ribs protect the heart and lungs).
Muscles are attached to bones. When muscles pull, your bones move — that is how you walk, lift and smile.
5. Forms of Energy
Energy comes in different forms and can change from one to another:
- Light, heat, sound, electrical and movement energy.
A torch changes chemical energy in the battery into light. A radio changes electrical energy into sound.