Download Intro to optics presentation

What is Optics?
• Study of the behaviour and properties of light
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How light interacts with matter
Natural occurring optical phenomena and constructed optical
instruments
• Can you think of optical devices that have
impacted our lives (medical, scientific,
personal)?
• How have each affected science, society, and
the environment?
Technologies that use light
•Telescope
Contacts
•Cameras
Magnifying glass
•Microscopes
Monocles
•Fiber Optics
Binoculars
•Lasers
TVs/screens
•Glasses
Projector
•and
•Light Sabers
•**Think about which of these you would like to do your
presentation on. We will pick 5 together next week**
What is light?
• Light is a form of radiant energy that is visible
to the human eye.
• Light is a type of electromagnetic wave.
• Lights travels in straight lines.
• There are natural sources of light such as light
from the sun, stars, fire, and lightening.
• Light is produced by some plants and animals.
• Artificial light is produced through human
technology.
• We need light to see.
Electromagnetic spectrum
• Visible light is only a tiny fraction of the
energy that surrounds us every day.
• We are surrounded by invisible light-like
waves called electromagnetic radiation.
• The entire range of electromagnetic radiation
is called the electromagnetic spectrum.
Electromagnetic radiation is a wave pattern of electric
and magnetic fields that can travel through empty
space.
In a vacuum, electromagnetic radiation propagates at the sp
Wave Model
• A wave is a disturbance that transfers energy
from one point to another without
transferring matter, i.e. a water wave
• The movement of energy allows the wave to
do work.
• Wave properties:
- crest
- wavelength
- trough
- amplitude
- rest position - frequency
Period is the amount of time it takes to complete
one cycle.
Frequency (Hz) is the number of cycles that can
occur in a given time period.
The Wave Equation
v  f
• Does this make sense?
• How long would it take light to travel around
the world?
White light is colourful
• How can white light allow us to see so many
different colours?
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White light is composed of a combination of all the
colours of the rainbow –the visible spectrum.
• The difference between colours of light is that
each colour has a different wavelength and
frequency.
Additive Colour Theory of Light
• White light is composed
of different wavelengths
(colours) of light.
• Primary colours of light:
red, green, blue
• Secondary colours of light:
magenta, yellow, cyan
Subtractive Colour Theory of Light
• Coloured matter selectively absorbs different colours
(wavelength) of light.
• The colour you see when you look at an object
depends on the wavelengths that are reflected. The
colours that are absorbed are “subtracted” from the
reflected light that is seen by the eye.
• The subtractive theory applied to pigments and dyes.
• Primary subtractive colours: cyan, magenta, yellow
• Secondary subtractive colours: red, green, blue
Producing Visible Light
• Natural sources of light
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The Sun
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Stars, fire, lightning
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Bioluminescence
The ability of a plant or animal to produce light.
• Blue Planet: Amazing and weird creatures exhibit bioluminescence
https://www.youtube.com/watch?v=UXl8F-eIoiM
Artificial Light pg. 394-399
How does it work?
Where is it used?
Look at efficiency and environmental impacts
1) Incandescent Light pg. 394
2) Fluorescent Light pg. 394
3) Phosphorescent Light and Chemiluminescence pg. 395
4) Triboluminescence and Electric Discharge pg. 396
5) Light Emitting Diode and Organic-light emitting display pg. 397
6) Plasma Displays and Liquid Crystal Displays pg. 398-399
Fun with diffraction grating glasses
• Useful for analysing and comparing the light
produced by various sources.
• They function like a prism,
splitting light into its spectrum
component colours.
• Analyse the light from various
sources and compare the
spectra of each.
Ray Model of Light
• Light is represented as straight lines, which show the direction that light
travels.
• We draw ray diagrams to show the path that light takes after it leaves its
course.
Shadows
Use ray diagrams to help explain the size and location of shadows
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Why are some shadows sharp and well defined while other shadows have
less distinct edges?
Shadows
• A small light source casts shadows that are
sharp and well defined. This area is called the
umbra.
• If the light source is
large compared to the
object blocking the light,
a penumbra will form in
the shadow.