WHAT HAPPENS WHEN LIGHT HITS AN OBJECT?

Science 10 – Optics

How do we show the direction in which light is travelling? To trace the straight-line path that light

travels, scientists use an arrow called a ray

You will use diagrams that involve rays (ray diagrams) to help you understand and make predictions about the way light behaves

Reflection

Reflection is the process in which light ‘bounces off’ a surface and changes direction

How would you use a ray diagram to illustrate this?

Absorption

Absorption is the process in which light energy remains in an object and is converted into heat

Objects appear the colour they are because they absorb all colours of the spectrum except the one our eyes see (it is reflected)

The black ‘E’ below appears black because it absorbs all of the light that hits it (no light hits your eyes)

E

Absorption/Reflection

Transmission

Transmission is the process in which light travels through an object and continues travelling

Different objects transmit different amounts of light

There are 3 ways to describe transmission: Transparent Translucent Opaque

Transparent

If light is transmitted directly through an object without any change in direction, the object is transparent

What is an example of a transparent object?

Translucent

If light can penetrate an object but it is scattered in many directions, the object is translucent

What is an example of a translucent object?

Opaque

If an object absorbs or reflects light only and no light penetrates it, the object is opaque

What is an example of an opaque object?

Transparent/Translucent/Opaque

Ray Diagrams

If you had to draw ray diagrams for objects that were transparent, translucent and opaque, what would they look like??

Transparent Translucent Opaque

Ray Diagrams