Loading presentation...

Present Remotely

Send the link below via email or IM

Copy

Present to your audience

Start remote presentation

  • Invited audience members will follow you as you navigate and present
  • People invited to a presentation do not need a Prezi account
  • This link expires 10 minutes after you close the presentation
  • A maximum of 30 users can follow your presentation
  • Learn more about this feature in our knowledge base article

Do you really want to delete this prezi?

Neither you, nor the coeditors you shared it with will be able to recover it again.

DeleteCancel

Make your likes visible on Facebook?

Connect your Facebook account to Prezi and let your likes appear on your timeline.
You can change this under Settings & Account at any time.

No, thanks

Light & Optics PBL 2014

No description
by

Claudia Trottier

on 14 May 2014

Comments (0)

Please log in to add your comment.

Report abuse

Transcript of Light & Optics PBL 2014

Light & Optics PBL 2014
What is light?
Light is the natural agent that stimulates sight and makes things visible.

Sylvie
Gracie
Claudia
Created By:
Give at least 4 sources of natural light and 4 sources of man-made light.

Natural:
1. Sun
2. Stars
3. Fire
4. Lightning
Man-made:
1. Light bulb
2. Cameras
3. Stove
4. Televisions
What is the first basic principle of light and give me at least 3 examples of light being
transformed into other sources of energy.
The first baisc principle of light is that light is a form of energy. When light reaches a surface, it can be absorbed and transformed into other types of energy.
Examples:
> solar panels change light into heat energy
> solar cells change light into electricical energy
> plants change sunlight into chemical energy

The amount of energy a surface receives depends on the intensity of the light.
The more intense the light, the more light can be absorbed.

What are the 5 sources of light? Give a definition of each as well as an example.
- Incandescent Sources: An object heated to such a high temperature that it emits visible light
> Old Light bulbs
> Candle flames



Fluorescent Sources: When invisible ultraviolet light is absorbed by the particles of an object. The object then emits some of the energy as visible light.
> Fluorescent light bulbs

Phosphorescent Sources: The emission of light following exposure to and removal of a source of radiation.
> Exit signs in buildings
> Glowing hands on a hand watch

Chemiluminescent Sources: The emission of light resulting from chemical action and does not involve heat
> Glow sticks


Bio-luminescent Sources: An organism that relies on chemical reactions inside its body to produce light
> Jelly fish
> Fireflies
> Effulgent Fungi

What is the ray model of light and what does it tell you about light and shadows?
Demonstrate.
-The ray model of light helps you to predict where shadows will form and how large they will be
It also tells you that..
> Light travels in straight lines
> Objects farther away from the light source cast a smaller shadow and objects closer to the light cast a larger shadow

Explain what happens when light hits opaque, transparent, and translucent materials. Also give an example of each type of material. Do some demonstrations using examples of the following materials to show your knowledge of each material.
-Opaque Materials: When light strikes the surface of opaque materials, a shadow is formed
Ex. Walls
-Transparent Materials: When light hits a transparent material, the light goes through completely.
Ex. Glass
-Translucent Materials: When light hits a translucent material, a portion of the light energy reflects back from the surface of the material
Ex. Curtains
Translucent Materials: When light hits a translucent portion of the light energy reflects back from the surface of the material
Ex. Curtains

Translucent Materials: When light hits a translucent portion of the light energy reflects back from the surface of the material
Ex. Curtains

What does reflection mean?
Reflection is the process when light hits a surface and bounces back off that surface.
Translucent Materials: When light hits a translucent portion of the light energy reflects back from the surface of the material
Ex. Curtains

Explain the law of reflection
The angle of reflection equals the angle of incidence.
Ex. If the angle of incidence is 70˚ then the angle of reflection is 70.˚

.

Explain how images are formed in mirrors being sure to explain the following: Where does the image appear to be coming from, how does the image size appear in relation to the image, and how does the distance the object appears relate to the distance of the object?

-Images are formed in mirrors by Reflection. Reflection is when light hits a surface and bounces back off that surface. Light reflects off all parts of an object in all directions. All the rays from the object reflect off the mirror according to the law of reflection. The rays that reach your eye appear to be coming from behind the mirror because your mind knows that light travels in a straight line. Images in a mirror appear to be the same size as the reflected object and come from an equal distance from behind the mirror.
Explaining mirrors. Explain which way concave and convex mirrors bend, how an image appears in each
(with relation to distance and size) and where these types of mirrors are used. What are some everyday examples of how we use reflections (only give one example using mirrors)


Convex:

> Convex mirrors bulge out
> Images in a convex mirror appear smaller and farther away
> Convex lenses are used :
- in stores for security
- side mirrors in cars


Concave Mirrors:

> Concave mirrors bulge in
> Images in concave mirrors appear to be closer and longer than they actually are
> Concave mirrors are used on side mirrors in cars, these are often labeled – Objects appear closer than they actually are and concave mirrors are also used in shaving / make up mirrors.



Part A
Draw a diagram and label the following: incident ray, reflected ray, angle of incidence, angle of reflection, and normal line.
Part B
Part C
Part D
Part E
Part F
Show a picture of a light wave and make sure to label the following: Crest, trough, wavelength, amplitude and cycle
What is refraction?
Crest – The high parts of a wave

Trough – The low parts of a wave

Wavelength – The distance from crest to crest

Amplitude – The height or depth of a wave from rest position


Refraction is the blending of light when it
moves from one medium to another.
Explain what frequency is and what it is measured in.
Frequency is the rate at which a wave moves up and down. Frequency is measured in hertz or cycles (cycles are the movement of a wave from one crest to the next crest or one trough to the next trough) per second.
What is the Wave Model of Light?

The wave model of light says that light travels in waves.
How far light spreads out depends on how long the wavelengths are. Waves with longer wavelengths spread out more.

Why does light bend?
Light bends because it changes speed when moving between materials of different densities.
Does light travel more slowly or more quickly in dense material? Explain.
Light travels more slowly in dense material because in a gas the atoms travel very, very fast, in a solid they don't travel at all and in liquids they travel faster than a solid but slower than a gas. Think of light as atoms in a solid the light would move very slow, in a liquid: slightly faster and etc. It takes a longer time to travel in dense material because there are atoms everywhere all crammed together and they bounce and reflect off of each other which makes light travel a longer total distance.
Explain what the electromagnetic spectrum is and show a picture of this.
-The electromagnetic spectrum is the arrangement of visible light and invisible forms of radiant energy according to wavelength.
Light travels more slowly in dense material because in a gas the atoms travel very, very fast, in a solid they don't travel at all and in liquids they travel faster than a solid but slower than a gas. Think of light as atoms in a solid the light would move very slow, in a liquid: slightly faster and etc. It takes a longer time to travel in dense material because there are atoms everywhere all crammed together and they bounce and reflect off of each other which makes light travel a longer total distance.
What does the bending of light do to an image?
Give a definition of each of the parts of the electromagnetic spectrum and show examples of where we use this type of wave.
The bending of light makes the image to appear to be in a different location
-Radio Waves:
A wave useful for carrying sounds or pictures through the air
Uses of Radio Waves
> Broadcasting radio and T.V programs
> Radar
> Microwave ovens for cooking (microwaves are shortest wavelength and highest frequency of radio waves)

Infrared Radiation:
also known as Heat Radiation
Uses of Infrared Radiation
> Motion detectors
> Burglar alarms
> Heat lamps
> Thermographs

Ultra-Violet Radiation:
Energetic form of radiation that causes tanning
Depletion of the Ozone layer
> Ozone in the atmosphere protects us from Ultraviolet radiation
> UV radiation causes tanning
> Too much UV radiation can cause cancer


The bending of light makes the image to appear to be in a different location
Gamma Rays:
Gamma rays result from nuclear reactions and can kill cells
Use of Gamma Rays:
> Used to treat cancer cells with radiation therapy
What is the law of refraction? Use a refraction tank to demonstrate this.
- When light travels from one medium, to a more dense one the light will be bent towards the normal, and when it exits the denser medium into a less dense medium it will bend away from the normal. The new direction of light is called angle of refraction. The first discoverer seems to have been Thomas Harriot, who knew it by 1602, based on his observations in 1597 and 1598, but died before he could publish it.
Thanks for
watching!
Explain what the spectrum is and what are the seven colors of the spectrum? I have indicated an easy way to remember the colors in the notes, however I want you to come up with another mnemonic device to help remember the colors of the spectrum.
The spectrum is a band of colors, as seen in a rainbow, produced by separation of the components of light by their different degrees of refraction according to wavelength. The seven colours of the spectrum are Red, Orange, Yellow, Green, Blue, Indigo, and Violet.
Victoria Read Books Yesterday Instead of Gaming
Explain why objects appear the color they are.
It's a matter of selective absorption and reflection of the varying wavelengths of light. Our eyes and brain work together to interpret the different wavelengths of light as different colors. White light is composed of all possible wavelengths of visible light, and sunlight is very nearly white. Characteristics of various surfaces cause them to reflect or absorb certain wavelengths. The ones that are reflected to our eyes are what determine the color we perceive. To cite just a single example, if a ball is red, it reflects red light and absorbs the other colors. That’s why it appears red.
Explain why objects appear the color they are.
Explain why objects appear the color they are.
It's a matter of selective absorption and reflection of the varying wavelengths of light. Our eyes and brain work together to interpret the different wavelengths of light as different colours. White light is composed of all possible wavelengths of visible light, and sunlight is very nearly white. Characteristics of various surfaces cause them to reflect or absorb certain wavelengths. The ones that are reflected to our eyes are what determine the colour we perceive.

To cite just a single example:

If a ball is red, it reflects red light and absorbs the other colours. That’s why it appears red.
Explain the structures in our eyes that allow us to see light and colour. Where are these structures located?
Rods are structures that help detect light and cones are structures that help detect colors.
Rods and cones are located in the retina.

I want you to try and find out what the latest research says about how we really see light.
The retinas convert light energy into electrical energy which it sent to the brain. (Not Full Answer!)
X-Ray:
Radiation that can penetrate skin and muscle
Uses of X Rays
> Used in hospitals and dentist offices
Paul Villard, a French physicist, is credited with discovering gamma rays. Most sources put this in 1900, although I've seen a few sources use 1898. Villard recognized them as different from X-rays (discovered in 1896 by Roentgen) because the gamma rays had a much greater penetrating depth. It wasn't until 1914 that Rutherford showed that they were a form of light with a much shorter wavelength than X-rays
Wilhelm Roentgen, Professor of Physics in Worzburg, Bavaria, was the first person to discover the possibility of using electromagnetic radiation to create what we now know as the x-ray.
The difference in Fluorescence and Phosphorescence is how the light is made visible. Fluorescence lights when there isn't any excitation energy involved. Phosphorescence needs this energy supply to emit the light.
The Driving Question
Bibliography
Mr Shacks Light & Optics Notes
Full transcript