Making shadows
Transparent object let light shine through them. Opaque ones, like book, block the light and cast a shadow. Because light travels in straight lines, the shadow is the same shape as the book.

Reflecting light
When light hits something shiny, like a metal can, it bounces off it. This called reflection. Shiny flat surfaces are the best at reflecting light. Thing that do not reflect light look black, because they soak up the light that falls on them.

Bending light
When light travels from on substance to another, for example from air into glass, or from glass into water, it changes direction. This is called refraction. It explains why a drinking straw in a glass looks bent.

Focusing light
Lenses are designed to bend light in a particular way. The lenses in glasses help to bend light so that it makes an image on the back of the eye. Instead of being fuzzy, the image is sharp or 'focused'.

Starlight
Light from stars can take millions of years to reach us.