Madhurig at 13:00, 7 August 2018

2018-08-07T13:00:53Z

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Snehalathak at 06:12, 12 September 2017

2017-09-12T06:12:18Z

Madhurig at 07:43, 11 September 2017

2017-09-11T07:43:01Z

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Madhurig: Created page with "{| border = 1 |'''Visual Cue''' |'''Narration''' |- || '''Slide Number 1 ''' '''Title Slide ''' || Welcome to this tutorial on '''Bending Light ''', an interactive PhET simu..."

2017-09-07T11:29:31Z

Created page with "{| border = 1 |'''Visual Cue''' |'''Narration''' |- || '''Slide Number 1 ''' '''Title Slide ''' || Welcome to this tutorial on '''Bending Light ''', an interactive PhET simu..."

New page

{| border = 1
|'''Visual Cue'''
|'''Narration'''
|-
|| '''Slide Number 1 '''

'''Title Slide '''
|| Welcome to this tutorial on '''Bending Light ''', an interactive PhET simulation.

|-
| ''' Slide Number 2'''

'''Learning Objectives'''
|| In this tutorial we will learn,

How to use''' Bending Light, '''interactive PhET simulation.
|-
| '''Slide Number 3'''

'''Pre-requisites'''
|| To follow this tutorial,

Learners should be familiar with topics in high school science.
|-
| '''Slide Number 4'''

'''System Requirement'''
|| Here I am using -

Ubuntu Linux OS Version 14.04

Java version 1.7.0

Firefox Web Browser Version 53.02.2.
|-
| '''Slide Number 5'''

'''Learning Goals'''
|| Using this simulation we will learn,

Reflection of light

Refraction of light

Dispersion of light

How reflection and refraction varies with different material media.
|-
| ''' Slide Number 6 '''

'''Learning Goals'''
|| We will also learn to,

Use optical instruments like prism and lens.

Measure intensity of light.

Measure velocity of light and

View different wave patterns.
|-
|
|| Now let’s define reflection, refraction and dispersion.
|-
| '''Slide Number 7 '''

'''Reflection'''
|| '''Reflection''' is bouncing back of a light ray after hitting any surface.

For example- A mirror reflects the image of the observer.

|-
| '''Slide Number 8 '''

'''Refraction'''
|| '''Refraction''' is bending of a light ray, when it enters a medium.

Light changes its speed and angle of propagation as it enters a different medium.

For Example: Bending image of a Pencil in a beaker of water.
|-
| ''' Slide Number 9 '''

'''Dispersion'''
|| '''Dispersion '''is a process of splitting of white light into seven colours.

For Example, Formation of a Rainbow on a cloudy day.
|-
|
|| So, let's begin.

|-
| ''' Slide Number 10 '''

'''Link for PhET simulation'''

[http://phet.colorado.edu/ http://phet.colorado.edu]
|| Use the given link to download the simulation.

[http://phet.colorado.edu/ http://phet.colorado.edu]
|-
| Point to the file in Downloads folder.
|| I have already downloaded '''Bending light''' simulation to my '''Downloads''' folder.
|-
| Right click on '''bending-light_en.html''' file.

Select '''Open With Firefox Web Browser''' option.

Point to the browser address.
|| To open the simulation, right click on '''bending-light_en.html''' file.

Select '''Open With Firefox Web Browser''' option.

File opens in the browser.
|-
| Cursor on the interface.
|| This is the interface for '''Bending Light''' simulation.
|-
| Point to each screen.
|| The interface has three screens,

''' Intro '''

''' Prisms''' and

''' More Tools '''

|-
| Cursor on '''Intro '''screen.

Click on '''Intro''' screen.
|| Let us begin our simulation with '''Intro''' screen.

Click on '''Intro''' screen to open it.
|-
| Cursor on '''Intro '''screen.

Point to the '''Ray''' and '''Wave''' radio buttons.

Drag and move the '''laser''' pointer.
|| This screen has,

'''Ray''' and '''Wave''' radio buttons on the top left corner.

A movable '''laser''' pointer to turn on the light.

We can see green coloured arrows, when

mouse pointer is placed on the '''laser'''.

These arrows show the direction, in which the '''laser''' moves.

Click and drag the '''laser''' to move it from zero to 90 degrees.

Let us bring the '''laser''' to its default position.

|-
| Move the cursor to the bottom left.
|| Now let’s move onto the tools at the bottom left.
|-
| Point to the tool box.

Point to the '''protractor''' tool.

Point to '''Intensity''' tool.

Point to the '''Reset''' button.
|| Here we see a tool box.

It consists of a,

'''Protractor''' to measure angles

'''Intensity''' tool to measure intensity of light<br/>

Below the tool box we have a check box to show '''Normal'''.

A '''Reset ''' button is provided at the right hand side corner to reset the simulation.
|-
| Point to the radio buttons '''Ray''' and '''Wave'''.

Point to '''Ray'''.
|| Let us begin the simulation.

We can focus light in the form of a '''Ray '''or a '''Wave''' depending on what we choose.

By default '''Ray''' is selected.

To turn on the '''laser''' , click the red button on the '''laser''' pointer.
|-
| Point to the reflected and refracted ray.
|| Notice that '''laser''' light gets reflected and refracted.

|-
| Click and drag the '''laser''' .
|| Observe that, as we drag the '''laser''' pointer, angle of reflection and refraction changes.

|-
| Place the '''protractor''' on the normal.

Measure the angles.
|| Let’s use '''protractor''' tool to measure angle of,

incidence

refraction and

reflection.

Place the '''protractor''' at the intersection point of-

incident ray, normal, refracted and reflected rays.

Observe that angle of incidence is equal to angle of reflection.

Drag the '''protractor''' back to its place.

|-
| Move the cursor to right hand-side of the screen.

Point to the controls- to measure '''refractive index'''.
|| Next we will move on to, right hand side of the '''Intro''' screen.

Here, we have controls to measure '''refractive index''' in both the media.

|-
| Point to the slider.

Move the cursor to slider.

Drag the slider.

Point to index of Refraction.

Point to the value.

Drag the slider to '''Water'''
|| There is a slider to change the material medium. Or buttons to click.

Initially the slider is near '''Air'''.

As we drag the slider, medium changes from '''Air''' to '''Water''' and then to '''Glass'''.

When medium is changed the angle of refraction changes.

'''Index of Refraction(n)''' also changes.

We can see the changing value in the box.

Drag the slider back to '''Air''' in the upper medium.

By default slider is on '''Water''' in the lower medium.

Drag the slider and place it between '''Water''' and '''Glass''' in the lower medium.
|-
| Point to '''intensity''' tool.
|| Now lets measure the '''intensity''' of light using '''Intensity''' tool.

|-
| Click on '''Intensity '''tool.

Point to the '''magnifier''' and '''meter'''.
|| Click and drag the '''Intensity''' tool to the medium.

'''Intensity''' tool consists of a '''magnifier''' and a '''meter''' to measure '''intensity''' of light.
|-
| Drag and place.

Point to '''meter'''.
|| I will place the '''magnifier''' on the incident light.

Meter shows 100% intensity.
|-
| Drag and place.

Point to the meter.

Drag the slider.
|| Now drag and place the '''magnifier''' on refracted light.

Meter shows value as 86.08%.

Intensity decreases because it depends on the medium.

As we drag the medium slider, value on the intensity meter changes.

This is because angle of refraction changes.
|-
| Place the magnifier on reflected light.

Point to the meter.
|| Similarly place the '''magnifier''' on reflected light.

'''Meter''' shows value as 13.55%.

You can drag the slider to see a different value of intensity.
|-
| Point to the '''wave''' radio button.

Point to the bending.
|| Next change '''Ray''' to '''Wave''' and observe the '''bending of light'''.

|-
| Click on '''Prisms''' screen.
|| Now we will move on to '''Prisms''' screen.

Click on '''Prisms''' screen at the bottom of the interface.
|-
| Point various tools on the screen.
|| In this screen we have the following tools-

Slider to change the '''environment '''

'''Monochromatic ray '''

'''Monochromatic beam'''

'''White light '''

Slider to change '''wavelength''' of light.
|-
| Move the cursor to the bottom of the screen.

Point to '''prisms''',

Point to medium slider,

Point to Check boxes,

Point to '''Protractor'''.

Point to '''Reset''' button.

|| At the bottom of the screen we have-

''' Prisms''' and '''lenses'''

Slider to change the '''Objects '''.

Check boxes for '''Reflections''', '''Normal''' and '''Protractor'''.

'''Reset''' button is at the right hand-side bottom corner.
|-
| Point to the screw.

Change the direction using the screw.
|| '''laser''' has a screw provided at its end.

Direction of '''laser''' can be changed using the screw.

Here arrows indicate direction of motion.

'''laser''' can also can be moved up and down.
|-
| Click '''laser''' light.

Click on '''Reflections''' check box
|| Now let’s begin the simulation.

Click on '''Monochromatic beam'''.

Click on the '''laser''' light.

Click on '''Reflections''' check box to see multiple reflections.

|-
| Place the '''prism''' on the path.

Point the cursor to the path of light.
|| Place a '''Prism''' in the path of light.

You can see bending of light.

|-
| Move the '''wavelength''' slider gradually.

Point to the bending of light.
|| Move the '''wavelength''' slider gradually from red to violet.

Notice the bending of light as '''wavelength''' changes.
|-
| Point to the screw.

Drag the screw to change direction.

Notice the bending.

|| '''Prism''' is provided with a screw at its corner.

Drag the screw to change the direction of the '''prism'''.

As we change the direction notice the bending of light.

|-
| ''' Slide Number 11 '''

'''Assignment '''
|| As an assignment

Change prism to glass slabs and observe the bending of light.

|-
| Cursor on the screen.
|| Now will see dispersion of light using white light.

|-
| Click on White light tool.

Point to the dispersion.
|| Click on '''White light''' tool.

Observe the dispersion of light.
|-
| Drag the slider and observer.
|| Drag the '''Objects''' medium slider and observe the dispersion of light.

|-
| Place the lens in the path of the beam.

Point to multiple reflections.
|| Place a lens in the path of dispersed beam of light.

The dispersed light shows multiple reflections.

|-
| '''Slide Number 12 '''

'''Assignment '''
|| As an assignment

Use various lenses and observe the dispersion.

Change various '''Environments''' and observe the dispersion.

|-
| Cursor on the screen.
|| Now we move on to '''More Tools''' screen.

|-
| Click on '''More Tools''' screen.

Point to all the tools on the screen.
|| Click on '''More Tools''' screen.

'''More Tools''' screen has a combination of tools from '''Intro''' and '''Prisms''' screens.

|-
| Point to '''Speed''' and '''Time''' tool.

Point to '''Angles '''tool.
|| Tool box at the bottom has two additional tools:

'''Speed''' and '''Time.'''

At the bottom we also have '''Angles''' check box.

Click on the '''Angles''' check box.
|-
| Click on Wave radio.

'''Normal''' and '''Slow Motion'''

'''Play/Pause'''

'''Forward'''
|| Now we will change the '''laser''' light to Wave.

Additionally radio buttons-

'''Normal''' and '''Slow Motion '''

Also , '''Play/Pause''' and '''Forward''' buttons appear.
|-
|
|| let’s begin the simulation

|-
| Click on '''Time''' tool
|| Turn on the '''laser''' light.

Click on red button to turn on the '''laser''' pointer.

let’s use the '''Time''' tool.

Drag and place the '''Time''' tool in the medium.

'''Time''' tool has two '''magnifiers''' and a '''Meter'''.
|-
| Drag an place the '''Time''' tool.

Place the '''magnifiers''' on Incident and refracted waves.
|| Place one of the '''magnifiers''' on incident wave and observe the wave pattern.

Now place the other '''magnifier''' on the refracted wave.

Observe the wave pattern.

It shows a '''phase shift'''.

|-
| Place the '''magnifier''' on reflected ray.

Point to the reduced '''amplitude'''.
|| Place the '''magnifier''' on the reflected wave.

Observe that, the new wave pattern is with reduced '''amplitude'''.

This is because the reflected wave has much lower '''intensity'''.
|-
| Drag and place on the refracted wave.

Point to the speed.
|| Drag and place the '''Speed''' tool on the refracted wave.

The speed is 0.67 c.

Here c is velocity of light(3x10^8 m/s).

Value of speed decreases:

This is because velocity of light decreases in a material medium.
|-
| '''Slide Number 13'''

'''Assignment'''
|| As an assignment,

Change material medium and notice the change in speed and wave pattern.
|-
|
|| Let’s summarize.
|-
| ''' Slide Number 14 '''

'''Summary'''
|| In this tutorial we have learnt,

How to use '''Bending Light, '''interactive PhET simulation.
|-
| '''Slide Number 15'''

'''Summary'''
|| Using this simulation we have learnt,

Reflection of light

Refraction of light

Dispersion of light

How reflection and refraction varies with different material media
|-
| ''' Slide Number 16 '''

'''Summary'''
|| We have also learnt to,

Use optical instruments like prism and lens

Measure intensity of light.

Measure velocity of light and

View different wave patterns.
|-
| '''Slide Number 17'''

'''About Spoken Tutorial project'''
|| The video at the following link summarizes the Spoken Tutorial project.

Please download and watch it.

|-
| '''Slide Number 18'''

'''Spoken Tutorial workshops'''
|| The '''Spoken Tutorial Project '''team:

conducts workshops using spoken tutorials and

gives certificates on passing online tests.

For more details, please write to us.

|-
| '''Slide Number 19'''

'''Forum for specific questions:'''

Do you have questions in THIS Spoken Tutorial?

Please visit this site

Choose the minute and second where you have the question.

Explain your question briefly

Someone from our team will answer them.
|| Please post your timed queries on this forum.
|-
| '''Slide Number 20'''

'''Acknowledgements'''
|| This project is partially funded by Pandit Madan Mohan Malaviya National Mission on Teachers and Teaching.

|-
| '''Slide Number 21'''

'''Acknowledgement'''
|| Spoken Tutorial Project is funded by NMEICT, MHRD, Government of India.

More information on this mission is available at this link.

|-
|
|| This is Madhuri Ganapathi from IIT-Bombay signing off.

Thank you for joining
|-
|}

@@ Line 421: / Line 421: @@
 || Place a lens in the path of dispersed beam of light.
-The dispersed light shows multiple reflections.
+The dispersed beam of light shows multiple reflections.
 |-

PhET/C2/Bending-Light/English - Revision history

Madhurig at 13:00, 7 August 2018

Snehalathak at 06:12, 12 September 2017

Madhurig at 07:43, 11 September 2017

Madhurig: Created page with "{| border = 1 |'''Visual Cue''' |'''Narration''' |- || '''Slide Number 1 ''' '''Title Slide ''' || Welcome to this tutorial on '''Bending Light ''', an interactive PhET simu..."