Light travels in straight lines: Laser Part 1 – Properties of Light
Light travels VERY FAST – around 300,000 kilometres per second. At this speed it can go around the world 8 times in one second.
A luminous object like a candle radiates light in all directions We can use a light ray, which is a line and arrow showing the direction light is travelling, to show this.
Using Light rays to show the path of light striking an object is called Geometric Optics When light emitted from a source (the Sun) strikes an object (Earth), it is called Incident Light
Recall: A transparent object lets light pass through it easily 3 Classifications of Matter
Recall: A translucent object allows some light to pass through 3 Classifications of Matter
Recall: An opaque material does not let any light pass through it 3 Classifications of Matter
An image is a reproduction of an original object that is produced through the use of light A mirror is any polished surface that exhibits reflection Reflection is simply the bouncing back of light from any surface
Part 2 - Reflection Reflection from a mirror: Incident ray Normal Reflected ray Angle of incidence Angle of reflection Mirror
Activity In your lab groups, try Activity 11.5 on Page 482 and 483
The Law of Reflection Angle of incidence = Angle of reflection In other words, light gets reflected from a surface at ____ _____ angle it hits it. The same !!!
Clear vs. Diffuse Reflection Smooth, shiny surfaces have a clear reflection: Rough, dull surfaces have a diffuse reflection. Diffuse reflection is when light is scattered in different directions
Specular Reflection Specular reflection is the reflection of light off a smooth surface The water acts like a plane mirror Disco rules!
Using mirrors Two examples: 1) A periscope 2) A car headlight