Light Move in a Straight Line

Properties of light

It moves straight, can be reflected and can be refracted

Examples of situations where light moves in a straight line

Sunlight radiated through the trees & spotlights on stage

Formation of shadow

Shadows are formed when a moving light is obstructed by an object

The factor that affects the clarity of the shadow

The transparency and the opacity of the object

Transparent

Is a characteristic of an object (for example, clear plastic) that allows all light to pass through it

Translucent

Is a characteristic of an object (for example, coloured plastic) that allows some light to pass through it

Opaque

Is a characteristic of an object (for example, a manila card) that does not allow light to pass through it

Two factors that affect the size of the shadow

Distance between an object with the light source & Distance between an object with the screen

The condition that causes small shadow size

The distance between the object and light source is long

Factors affecting the shape of shadows

The position of the light source & the position/orientation of the object