PhET/C3/Gravity-and-Solar-system/English

Visual Cue	Narration
Slide Number 1 Title Slide	Welcome to this tutorial on Gravity and Solar System.
Slide Number 2 Learning Objectives	In this tutorial we will, Demonstrate Gravity and Orbits and My Solar System, PhET simulations.
Slide Number 3 System Requirement	Here I am using- Ubuntu Linux OS version 14.04 Java version 1.7.0 and Firefox Web Browser version 53.02.2
Slide Number 4 Pre-requisites	To follow this tutorial, Learner should be familiar with topics in high school science.
Slide Number 5 Learning Goals	Using these simulations we will - Describe the relation between Sun, Earth, Moon and satellite. Study the effect of mass and distance on gravitational force. Explain how gravity controls the motion of our solar system.
Slide Number 6 Learning Goals	Identify the variables that affect the strength of gravity. And determine the gravitational force.
Slide Number 7 Solar System	In our solar system, all the celestial objects revolve around the Sun. These objects are planets, moons, comets, asteroids, meteors and meteorites.
Slide Number 8 Gravitational Force	There exists a force of attraction between the Sun and the celestial objects. This force of attraction is gravitational force.
	Let us begin the demonstration.
Slide Number 9 Link for PhET simulation http://phet.colorado.edu	Use the given link to download the simulation. http://phet.colorado.edu
Point to gravity-and-orbits_en.html file.	I have already downloaded Gravity and Orbits simulation to my Downloads folder.
Right-click on gravity-and-orbits_en.html file. Click on Open With Firefox Web Browser Option. Point to Gravity and Orbits simulation.	To open the simulation, right click on gravity-and-orbits_en.html file. Select Open With Firefox Web Browser Option. Simulation opens in the browser.
Point to Gravity and Orbits simulation.	This is the interface of Gravity and Orbits simulation.
Point to Model and To Scale screens.	The interface has two screens. Model To Scale.
Point to Model screen.	Let us begin our demonstration with Model screen.
Click on Model screen. Point to the box. Point to the four systems.	Click on Model screen to open it. On the right side of the screen you can see a box. It has four solar system like models.
Point to the arrow button.	Next to models there is a gray coloured, Reset button. This button sets the solar system to its default state.
Point to the on and off radio-buttons.	We can select Gravity, using on and off radio buttons.
Point to the check-boxes.	Below Gravity, we have check-boxes for- Gravity Force Velocity Path and Grid .
Click on all the check-boxes.	Click on all the check-boxes.
Point to box. Point to Star and Planet sliders.	Below this box we have another box. It consists of sliders to change the mass of Star and Planet.
Point to Fast Forward, Normal and Slow motion radio buttons. Point to Normal radio button.	Bottom of the screen we have, Fast Forward, Normal and Slow motion radio buttons to change the animation speed. By default Normal speed is selected.
Point to Rewind, Play/Pause and Step buttons.	Also there are Rewind, Play/Pause and Step buttons.
Point to Clear button.	Clear button to reset the Earth Days count.
Point to Reset button.	Reset button to reset the simulation.
Point to Sun and Earth. Click on Play button. Point to the orbit.	By default Sun and Earth system is selected. Now click on Play button. Notice that, Earth revolves around the sun along a circular path. This circular motion is due to centripetal force.
Slide Number 10 Centripetal Force	Centripetal force causes change in acceleration and keeps the body moving along the circular path. This force acts towards the center.
Point to the orbit. Point to change in direction of earth in orbit.	This circular path is its orbit. Earth changes its direction of revolution at every point on the orbit.
Point to Earth's velocity perpendicular to Gravity force.	Notice that, Direction of Earth's velocity is perpendicular to Sun's Gravitational pull.
Cursor on interface.	Now Let us count Earth Days.
Click on Reset arrow button.	Click on Reset arrow to bring the sun and earth to its default position.
Point to Earth Days.	Observe the changes in the Earth Days as earth orbits the sun.
Click on Slow Motion radio-button.	Now we will change the animation to slow to count the days precisely.
Click on Pause button. Point to Earth Days.	Click on Pause to pause the simulation. Earth takes 365 days to complete one revolution.
Cursor on interface.	Next we will see what happens to earth in the absence of gravity.
Click on off radio-button of Gavity. Click on Normal radio-button.	Click on off radio button. Now we will change the animation to normal.
Click on Play button. Point to straight line.	Then click on Play button. Observe that, In the absence of Gravity, Earth files off along a straight line. This motion is tangential to the circular path.
Click on Return Objects button. Point to the earth.	Click on Return Objects button. Earth will return to its default position.
Cursor on the interface.	Now we will see the effect of change in mass on an orbit.
Point to Star Mass slider. Drag Star Mass slider towards 1.5. Point to Sun.	By default the Star Mass slider is at Our Sun. Let's drag the Star Mass slider towards 1.5. As you drag, observe the increase in size of the star.
Click on Gravity radio-button >> Play button. Point to the orbit. Point to elliptical path.	Next, click Gravity's on radio button and then Play button. Observe the path of the orbit. Earth now moves in an elliptical path. Size of the orbit also becomes small.
Point to the sun. Point to Earth Days.	Here sun is not at the center of the orbit. Note that, Earth Days decrease with the increase in the mass of the sun.
Drag Planet Mass slider towards 1.5. Point to the Gravity force.	Drag the Planet Mass slider towards 1.5. Notice that force of gravity between them increases.
Click on Pause button.	Click on Pause button to pause the simulation.
Click on planet >> drag the planet away from sun. Click on Play button.	Click on the planet and drag it away from the sun. Click on the Play button.
Point to Gravity force arrow.	Observe that, Gravitational force decreases with increase in the distance between planet and sun.
Click on Pause button. Click on Reset button.	Click on Pause button. Click on Reset button to reset the system.
Click on Sun, Earth and Moon system.	Now select Sun, Earth and Moon system.
Drag the slider to + sign.	Drag the slider towards + sign to zoom in the view.
Click on Play button.	Then click on Play button.
Point to pink coloured orbit. Point to earths circular orbit.	Notice that, moon is in spiral orbit with earth while earth is in circular orbit with sun.
Point to the moon in orbit.	Here moon is a satellite of the earth.
Slide Number 11 Assignment	As an assignment, Using Model screen, Explore earth, moon and earth, satellite systems.
Cursor on To Scale screen.	Now we will move on to To Scale screen.
Click on To Scale screen.	Click on To Scale screen at the bottom of the interface.
Point to To Scale screen. Point to Mass and Measuring Tape check-boxes.	To Scale screen has same tools as that of Model screen. This screen has two additional check-boxes- Mass and Measuring Tape
Click on Mass, Path and Grid check-boxes.	Click on Mass, Path and Grid check-boxes.
Point to the sun and earth system.	By default sun and earth system is selected.
Point to the Star and Planet masses.	Here, star's mass is 333 thousand Earth masses and planet's mass is 1 Earth mass.
Click on Play button. Click on Pause button.	Click on Play button to show the path of revolution. Then click on pause button.
	Lets measure the distance between star and Earth.
Click on Measuring Tape check-box.	Check against Measuring Tape check-box.
Uncheck Mass check-box.	Uncheck Mass check-box. This will enable us to measure the distance precisely.
Drag zoom in slider.	Drag the zoom in slider towards + sign to zoom in the view.
Drag Measuring Tape on star and then to planet. Point to the distance. Point to 91503 thousand miles.	Place the Measuring Tape on star and drag the other end to the planet. Note the Distance between star and planet. It is 91503 thousand miles. This value may vary a little in your case because sun is also in motion.
Cursor on the interface.	Let us calculate gravitational force between Earth and sun.
Slide Number 12 Universal Law of Gravitation	Universal law of gravitation- Force of attraction between any two objects is proportional to the product of their masses. It is inversely proportional to the square of the distance between them.
Slide Number 13 Universal Law of Gravitation	This force is along the line joining the centers of two objects.
Slide Number 14 Calculation of Gravitational Force F=(G x M x m)/d^2 G= 6.67 x 10-11Nm2/kg2 M=1.989 x 1030 kg m=5.972 x 1024 kg d = 91353 x 103 miles 1 mile = 1.609 x 103 m F= [(6.67 x 10-11)(1.99 x 1030)(5.97 x 1024)]/[(91503 x 103 x 1.609 x 103)2] F=(79.27 x 1043)/(2.165 x 1022 ) F=3.6 x 1022N	Gravitational force is calculated by using following formula where G is universal gravitation constant capital M is mass of sun small m is mass of earth and d is distance between earth and planet We substitute the values of G, capital M, small m and d in this formula. This will give us the value of the Gravitational force between sun and Earth. The value is 3.6 x1022 N(newton).
Slide Number 15 Assignment	As an assignment, Using To Scale screen, Determine the gravitational force between Earth and satellite.
	Now we will move on to My Solar System PhET simulation.
Point to the file in Downloads folder.	I have already downloaded My Solar System simulation to my Downloads folder.
To open Java file. Press Ctrl, Alt and T keys. Type cd Downloads and press enter.	To run the simulation, open the terminal. At the prompt type cd Downloads and press Enter.
Type java space hyphen jar my-solar-system_en.jar press Enter. Point to the Interface.	Then type, java space hyphen jar space my-solar-system_en.jar and press Enter. My Solar System simulation opens.
Cursor on the interface.	This is the interface of My Solar System simulation.
Point to drop down box. Click on drop down arrow and scroll down.	Screen has a system drop-down box on the right side. Here we can select a pair of solar systems of our choice.
Point to box. Point to Start, Stop and Reset buttons.	Below the drop-down box there is another box. It consists of Start, Stop and Reset buttons.
Point out to System Centered Show Traces Show Grid and Tape Measure check-boxes.	We have check-boxes for System Centered, Show Traces, Show Grid and Tape Measure. Use these check-boxes as an when required.
Point to slider.	There is a slider to control the speed of animation.
Point to the Initial Settings. Point to the mass, position and velocity values. Point to radio-buttons.	Screen is provided with Initial Settings at the bottom. Here we can input the mass, position and velocity values in their respective boxes. We can also use radio-buttons to select a number of bodies.
Click on drop down arrow.	Now click on drop down arrow.
Scroll to Sun, planet, comet>> click on it.	Scroll to Sun, planet, comet and click on it.
Point to planet, sun and comet.	We see 3 colored objects planet, sun and comet.
Point to red coloured arrow. Point to V.	Red coloured arrow indicates the velocity. It is a vector quantity indicated by V in circle.
Click on Start button. Point to orbit of comet.	Click on Start button and observe the orbits. Comet moves around the sun in an elliptical orbit.
Click on Stop button.	Click on Stop button.
Place cursor on Sun, Planet and comet.	Hover the mouse over Sun, Planet and comet to get their mass, current position and velocity.
Click on start button.	Click on start button.
Point to comet.	After a few revolutions the comet collides with the Sun and disappears.
Click on drop down box>>>click on Start button. Point to orbits. Click on Stop button. Hover the mouse on the bodies.	Select Four star ballet and click on Start button. Observe the orbits. Then click on Stop button. Hover the mouse on the bodies to get their mass, position and velocity.
Slide Number 16 Assignment	As an assignment, Select various systems and observe the orbits. Change the Initial settings and observe the changes in the orbits and Explain the observation.
	Let us Summarise.
Slide Number 17 Summary	In this tutorial we have demonstrated, How to use Gravity and Orbits and My Solar System, PhET simulations.
Slide Number 18 Summary	Using this simulations we have, Described the relation between Sun, Earth, Moon and Satellite. Studied the effect of mass and distance on gravitational force. Explained how gravity controls the motion of our solar system.
Slide Number 19 Summary	Identified the variables that affect the strength of gravity. Determined the gravitational force.
Slide Number 20 About Spoken Tutorial project	The video at the following link summarizes the Spoken Tutorial project. Please download and watch it.
Slide Number 21 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 22 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 23 Acknowledgements	This project is partially funded by Pandit Madan Mohan Malaviya National Mission on Teachers and Teaching.
Slide Number 24 Acknowledgement	Spoken Tutorial Project is funded by NMEICT, MHRD, Government of India. More information on this mission is available at this link.
	This is Meenal Ghoderao from IIT Bombay. Thank you for joining.

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