Light

​2 Reflections

​Reflection

• A reflection is when light reflects off an object (or surface)

​(bounce off)

​Reflection

• Rough objects reflect light in all directions

• This is called diffuse reflection

​Reflection

• Smooth objects, like mirrors, reflect light in the same directions

• This is called specular reflection

​Reflection

​Reflection

​angle of incidence

​angle of reflection

​Source of Light

​Eye

​Reflected Ray

​Reflection

​

• The light rays that hit the mirror/surface are called incident rays

• ​The rays of light that are reflected are called reflected rays

• The normal line is ALWAYS drawn at right angles to the mirror/surface​

​

Open Ended

Outline the difference between a diffuse and specular reflection

Draw

Complete the ray diagram. Draw and label the components of a reflection

Draw

Draw the reflected ray

​Mirrors

​

• When you look into a flat mirror, you see a virtual image

• The image appears to be the same distance from the mirror as the real object is in the reflection of the mirror

• The object in the mirror appears the same size but it is reversed​

​

​Mirrors

• same size

• same distance from the surface of the mirror

​Reflection image is reversed

Open Ended

Outline two similarities and one difference between the image and its mirror reflection

Draw

Draw the virtual image formed in the mirror

Draw

Draw the virtual image formed in the mirror

​1 How do we see things?

​How do we see things?

• We see things when light reflects off an object into our eyes

• Light is made by luminous objects such as the Sun or a light bulb

• Objects that do not make light are called non-luminous

​1. Light ray travels away from the sun in all directions

​2. A light ray reflects off the pencil

​3. The reflected ray enters the eye and the boy sees the pencil.

​Note: Follow the path of the light ray

​How do we see things?

• Light travels in straight lines

• It travels very fast (much faster than sound)

• Light does not need a medium to travel so it can travel through space

  • medium means material (solid, liquid, or gas)

• The speed of light in vacuum is 300,000,000 meters per second

  • vacuum means outer space

Multiple Choice

Sun

• Luminous

• Non-luminous

Multiple Choice

Moon

• Luminous

• Non-luminous

Multiple Choice

Mirror

• Luminous

• Non-luminous

Multiple Choice

Cat's eyes

• Luminous

• Non-luminous

Multiple Choice

TV (turned ON)

• Luminous

• Non-luminous

Multiple Choice

TV (turned OFF)

• Luminous

• Non-luminous

Open Ended

Outline the difference between luminous and non-luminous objects

Open Ended

How do we see non-luminous objects?

Draw

Outline, using ray diagram, how the boy sees the TV

Draw

Outline, using ray diagram, how the man sees the cat