light. what is light? light is composed of particles called photons which are massless bundles of...
TRANSCRIPT
What is Light?
• Light is composed of particles called photons which are massless bundles of concentrated electromagnetic energy and the travel in waves. Transverse Waves
• 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 light-year is the distance light travels in one year and is a unit of measure.
• Light travels much faster than sound. For example:
1) Thunder and lightning start at the same time, but we will see the lightning first.
2) When a starting pistol is fired we see the smoke first and then hear the bang.
Electromagnetic
• Electromagnetic waves- is energy traveling in a wave that is partially electric and partially magnetic.
• Electromagnetic Spectrum- all the electromagnetic waves that reach earth.
Electromagnetic Spectrum
• Radio, microwaves, infrared, visible light, ultraviolet, x-rays and gamma rays
• Organized from longest wavelength to shortest
• We have various uses for each type of wave
Color
• White light is not a single color; it is made up of a mixture of the seven colors of the rainbow.
We can demonstrate this by splitting white light with a prism:
This is how rainbows are formed: sunlight is “split up” by raindrops.
Objects and Light
• Transparent Objects- visible light can pass through them. Example: Clear glass
• Opaque Objects- No light passes through them . Example wood, bricks etc.
• Translucent Object- some light passed through . Example: Frosted Glass
• ShadowsA shadow is formed where light can’t reach.The larger the light source the larger the shadow.
Shadows are places where light is “blocked”:
Rays of light