View source for Apps-On-Physics/C2/Keplers-laws/English

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|-
|| '''Visual Cue'''
|| '''Narration'''
|-
|| '''Slide Number 1'''

'''Title Slide'''
|| Welcome to the Spoken Tutorial on '''Kepler's Law'''.
|-
|| '''Slide Number 2'''

'''Learning objective '''
|| In this tutorial we will demonstrate,

* '''Kepler's First Law''' and
* '''Kepler's Second Law''' '''Apps'''.
|-
|| '''Slide Number 3'''

'''System Requirements'''
|| Here I am using,

* '''Ubuntu Linux''' OS version 16.04
* '''Firefox web browser''' version 62.0.3
|-
|| '''Slide Number 4'''

'''Pre-requities'''

'''https://spoken-tutorial.org'''
|| To follow this tutorial, learner should be familiar with '''Apps on Physics'''.

For pre-requisitie tutorials please visit this site.
|-
|| '''Slide Number 5'''

'''Learning Goals'''
|| Using these '''Apps''' we will,
* Demonstrate '''Kepler's first law'''
* Calculate '''Aphelion''' and '''Perihelion''' distances
* Demonstrate '''Kepler's second law'''
|-
|| '''Slide Number 6'''

'''Link for Apps on physics '''.

'''https://www.walter-fendt.de/html5/phen'''
|| Use the given link to download the '''Apps'''.

'''https://www.walter-fendt.de/html5/phen'''
|-
|| Point to the Downloads folder.
|| I have already downloaded '''Apps on Physics''' to my '''Downloads''' folder.
|-
|| Double click on '''html5phen''' folder.

Double click on '''phen''' folder.
|| Double click on '''html5phen''' folder, then double click on '''phen''' folder.
|-
|| Right-click on''' keplerlaw1_en.htm''' file.

Select option '''Open With Firefox web Browser''' option.
|| Right-click on''' keplerlaw1_en.htm '''file.

Select the option '''Open With Firefox web Browser'''.

'''Kepler's First Law App''' opens in the '''browser'''.
|-
|| Point to show the law in Pink colour.
|| Here is the '''Kepler's First Law of undisturbed planetary motion'''.

It states that, '''The orbit of each planet is an ellipse and the Sun is at one focus'''.
|-
|| Scroll down the screen.
|| Let us scroll down the screen.
|-
|| Point to the green panel.
|| The green control panel shows the parameters that we can change.
|-
|| Click on drop down list and point the planets and '''Halley's Comet'''.

Point and show '''Mercury'''.
|| From the drop down list select any planet or '''Halley's Comet'''.

By default '''Mercury''' is selected.
|-
|| Point to '''Semimajor axis'''.
|| Here we can change the '''Semimajor axis''' from 0.1 to 100 '''AU'''.
|-
|| Highlight the wordings from the interface.
|| These lengths are in astronomical units.

'''1AU = 1.495 X 10^11 m '''

This is the average distance between the Earth and the Sun.
|-
|| Point to '''Numerical eccentricity'''.
|| The''' Numerical eccentricity''' should be less than 1.
|-
|| Point to '''Semiminor axis''' and '''Distance from the Sun'''.
|| The '''App''' automatically calculates the '''Semiminor axis''' and '''Distance from the Sun'''.
|-
|| Under '''Distance from the Sun''' point to '''Currently'''.
|| Since the planet is revolving around the Sun, its current distance  changes continuously.
|-
|| Point to '''Minimum''' and '''Maximum Distance from the Sun'''.

Point to '''Minimum''' value.

Point to '''Maximum''' value.
|| The '''Mercury's Minimum''' and '''Maximum''' '''Distance from the Sun''' is measured.

'''Minimum''' measured value is '''0.307 AU'''.

And '''Maximum''' measured value is '''0.467 AU'''.
|-
|| Move the cursor at the bottom of the green panel and point to '''Elliptical orbit'''.

'''Axes''' and '''Connecting lines''' check-box.
|| At the bottom of the green panel there are three check-boxes.

'''Elliptical orbit''',
'''Axes''' and 
'''Connecting lines'''.
|-
|| Click on '''Elliptical orbit''' check-box.
|| Click on '''Elliptical orbit''' check-box.
|-
|| Point to the orbit and positions of''' Aphelion''' and '''Perihelion'''.
|| Observe that the orbit now has two positions, namely '''Aphelion''' and '''Perihelion'''.
|-
|| Click on '''Pause''' button.
|| Click on '''Pause''' button to pause the simulation.
|-
|| Point to the''' Maximum''' and '''Minimum''' under '''Distance from the Sun'''.
|| '''Aphelion''' is the '''Maximum''' distance and '''Perihelion''' is the '''Minimum''' distance from the Sun.
|-
|| Click on '''Connecting lines''' check-box.
|| Select '''Connecting lines''' check-box.
|-
|| Point to F and F prime.
|| Here we can see the '''foci F''' and '''F prime''' of the elliptical orbit.
|-
|| Point to the connecting lines and foci.
|| Note that the connecting lines between the planet and the '''foci''' are drawn.
|-
|| Click on '''Resume''' button.
|| Click on the '''Resume''' button.
|-
|| Select the  '''Axes''' check-box.
|| Select the '''Axes''' check-box.
|-
|| Point to the lines.
|| Here we can see that semi-major axis and semi-minor axis are drawn.
|-
|| Cursor on the interface.
|| Let us calculate the '''Aphelion''' and '''Perihelion''' distances of Mercury using the formula.
|-
|| '''Slide Number 7'''

'''Aphelion and Perihelion Distance'''

'''R<sub>a</sub><nowiki>=a(1+e)   </nowiki>R<sub>p</sub><nowiki>=a(1-e)</nowiki>'''

'''Where,'''

'''R<sub>a</sub> is Aphelion distance (Maximum)'''

'''R<sub>p </sub>is Perihelion distance(Minimum)'''

'''a is semimajor axis'''

'''e is eccentricity'''
|| Formula to calculate '''Aphelion''' and '''Perihelion''' distances:

'''R<sub>a</sub><nowiki>=a(1+e)</nowiki>''' '''R<sub>p</sub><nowiki>=a(1-e)</nowiki>''' 

Where,

* R<sub>a</sub> is '''Aphelion''' distance.

* R<sub>p </sub>is '''Perihelion''' distance.

* a is semi-major axis.

* e is '''eccentricity'''.
|-
|| '''Slide Number 8'''

'''Tabular Column'''
|| Let us make a tabular column to show planets, '''Eccentricity''', '''Aphelion''' and '''Perihelion''' distances.
|-
|| '''Slide Number 9'''

'''Aphelion and Perihelion Distances'''

'''R<sub>a</sub><nowiki>=a(1+e) </nowiki>'''

'''<nowiki>=</nowiki>0.387(1+0.206)'''

'''<nowiki>=0.466 AU</nowiki>'''

'''R<sub>p</sub><nowiki>=a(1-e)</nowiki>'''

'''<nowiki>=0.387(1-0.206)</nowiki>'''

'''<nowiki>=0.307 AU</nowiki>'''
||Let us calculate the '''Maximum''' and '''Minimum''' distance of Mercury from the Sun.

Substitute the values of '''Semi-major axis''' and '''eccentricity''' in the formula from the  '''App'''.

These are the calculated values of the '''Aphelion''' and '''Perihelion''' distances.

Now we will compare these values with the ones shown in the '''App'''.
|-
|| Highlight the values of '''Minimum''' and '''Maximum''' distance.
|| Observe that the values are comparable.
|-
|| Open drop down list and select Venus.
|| From the drop down I will select Venus.

Observe that the values have changed for Venus.
|-
|| '''Slide Number 10'''
'''Tabular Column'''

Point to values of '''Minimum''' and '''Maximum''' distance.
|| Similarly I have calculated the '''Maximum''' and '''Minimum''' distance for Venus.
And entered these values in the table.
|-
|| '''Slide Number 11'''

'''Assignment'''

Calculate the '''Aphelion''' and '''Perhelion''' distances of the other planets.

Use the values of semi-major axis and '''eccentricity''' shown in the '''App'''.

Complete the table and verify the values with the ones shown in the '''App'''.

|| As an assignment 

* Calculate the '''Aphelion''' and '''Perhelion''' distances of the other planets.

* Use the values of semi-major axis and '''eccentricity''' shown in the '''App'''.

* Complete the table and verify the values with the ones shown in the '''App'''.
|-
|| Click on the drop down list and select the '''Halley’s comet'''.
|| From the drop down list select '''Halley’s comet'''.
|-
|| Point to show the orbit.
|| Observe that the orbit of '''Halley’s comet''' is different from the other planets.
|-
|| Point to the sun.
|| It's orbit around the Sun is highly elliptical.
|-
|| Point to numerical eccentricity.
|| This is because the numerical '''eccentricity''' of the '''Halley’s comet''' is close to 1.
|-
|| point to semi-major and semi-minor axis.
|| Therefore there is a large difference in the values of semi-major and semi-minor axis.
|-
|| '''Slide Number 12'''

'''Halley’s Comet'''

Halley’s comet is a periodic comet. 

It returns to Earth’s vicinity in about every 75 years.

A comet appears as a bright head with a long tail.

The tail of a comet is always directed away from the Sun.
|| Let us know more about Halley’s comet.

* Halley’s comet is a periodic comet.

* It returns to Earth’s vicinity in about every 75 years.

* A comet appears as a bright head with a long tail.

* The tail of a comet is always directed away from the Sun.
|-
|| 
|| Now we will move on to the next '''App'''.
|-
|| To open the '''App''' right click on '''keplerlaw2_en.htm''' and '''Open With Firefox Web Browser'''.
|| To open the '''App''' right click on '''keplerlaw2_en.htm''' and '''Open With Firefox Web Browser'''.
|-
|| Point to Kepler's second law within the pink box.
|| The '''App''' opens with '''Kepler's Second Law of the undisturbed planetary motion'''.
|-
|| Highlight the Law from the simulation.
|| The law states that,

'''The line joining the planet to the Sun sweeps out equal areas in equal intervals of time'''.
|-
||Scroll down the screen.
||Scroll down to see the interface.
|-
|| At the bottom of the green panel point to 

'''Distance from the Sun''' and '''Velocity'''.
|| In the green control panel, '''App '''measures the '''Distance from the Sun''' and '''Velocity'''.
|-
|| Point to '''Currently''' under '''Velocity'''.
|| The current velocity of the planet is changing continuously as the planet is revolving.
|-
|| Point to the '''Minimum''' and '''Maximum''' velocity.
|| The '''Minimum''' and '''Maximum''' velocity of the planet is measured here.
|-
|| Point to the '''Sectors''' and '''Vector of velocity''' check-boxes.
|| At the bottom there are two check-boxes, '''Sectors''' and '''Vector of velocity'''.
|-
|| Point to '''Sectors'''.

Drag and show the change.
|| By default '''Sectors''' is selected.

Next to the '''Sectors '''check-box, a slider is provided to change the area of the '''sector'''.
|-
|| Click on '''Vector of velocity''' check-box.
|| Select '''Vector of velocity'''.
|-
|| Point to the vector.
|| Here the black velocity vector shows the direction of velocity of the planet.
|-
|| Point to show the '''Maximum velocity'''.
|| The maximum velocity with which '''Mercury''' revolves is 59.1 km/s.
|-
|| Point to the value of velocity.

From the drop down select Jupiter and point to the velocity.

Planets far away from Sun have less velocity as compared to the planets that are near.
|| 
* Mercury is the closest planet to the Sun so it moves with a greater velocity.

* Now I will show the velocity for  Jupiter.

* Select Jupiter from the drop down list.

* Jupiter has less velocity than that of Mercury.

* Planets far away from the Sun have less velocity as compared to the planets that are near.
|-
|| cursor on the interface.
|| This is because the Sun’s gravitational pull is stronger on the planets that are close to it.
|-

|| Point to the two clocks.

Point to the ''' “T “ '''to show the unit.
|| Observe the pink and green digital clocks.

They record the time when the planet sweeps the '''sectors'''.

This time is expressed in orbital period.
|-
|| Drag the sector to show the changes.

|| Let’s drag the '''sector''' slider to maximum.
|-
|| Point to the clocks.
|| Notice that as we increase the area, time increases.
|-
|| '''Slide Number 13'''

'''Orbital period'''

|| The Orbital period is the time taken by the celestial object to go around the orbit of another celestial object.
|-
|| Select  '''Saturn''' from the drop down list.

Point to the pink and green clock which shows the sweep time.
|| Select the '''Saturn''' from the drop down list.

Observe that the sweep time for each '''sector''' in '''Saturn''' is same.
|-
|| '''Slide Number 14'''

'''Assignment'''

'''Select planets Venus and Uranus from the drop down list'''.

'''Observe the difference in the velocity'''.

'''Explain your observation'''.
|| As an assignment

Select planets Venus and Uranus from the drop down list.

Observe the difference in the velocity.

Explain your observation.
|-
|| 
|| Let us summarise
|-
|| '''Slide Number 15'''

'''Summary'''
|| Using these '''Apps''' we have,

* Demonstrated '''Kepler's First Law'''.

* Calculated '''Aphelion''' and '''Perihelion''' distances.

* Demonstrated '''Kepler's Second Law'''.
|-
|| '''Slide Number 16'''


'''Acknowledgement'''
|| These Apps were created by Walter Fendt and his team.
|-
|| '''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&nbsp;'''Spoken Tutorial Project&nbsp;''' team conducts workshops and gives certificates.

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'''

'''Acknowledgement'''
|| Spoken Tutorial Project is funded by MHRD, Government of India.
|-
|| 
|| This is Himanshi Karwanje from IIT-Bombay. 

Thank you for joining.
|-
|}