This unit covers some of the basic ideas in physics.

It covers the main subjects of light, sound and forces.

The following topics are covered-:

• light and shadow
• transparent or opaque
• how do we see things
• reflection
• refraction
• lenses
• prisms
• colours
• sound waves
• frequency
• how sound travels
• amplitude and frequency
• types of forces
• static electricity
• measuring forces
• friction
• mass and weight
• floating and sinking
• pressure
• effect of pressure