Name _______________________________________________ Date ______________________ Hour ______________
Gravity and Orbits: A pHET Exploration Activity
Objective: What is the relationship between mass and gravity?
1.
2.
3.
4.
5.
Go to: https://goo.gl/Qs8nLg (case sensitive)
Click on the “5” shield.
Choose “Model.”
Choose Sun and Earth.
Check all boxes.
6. Click
and describe what you see. Record your observations in the first row in the table below. Do not do
the 2nd row until you read directions for #7.
Mass
Effect on gravity, velocity, orbit path and OTHER observations
“Normal”
Sun: 1.0
Planet: 1.0
Sun: 1.0
Planet: 2.0
Sun: 1.0
Planet: 0.5
Sun: 2.0
Planet: 1.0
Sun: 0.5
Planet: 1.0
Sun: 0.5
Planet: 0.5
Sun: 2.0
Planet: 2.0
7. Click
, recheck the boxes, and increase the planet’s mass to 2.0. What happened to the orbit? (Note: you can zoom
in/out if needed using the scale tool on the left
.) Record in the table above.
8.
Click
, recheck the boxes, and change either the planet’s mass, the star’s mass or both based upon the given mass
criteria in the chart. Record your observations in the chart above.
9. Repeat until all rows are filled out.
10. Consider the information recorded in the chart. Which scenario(s) concluded with the planet leaving the orbit of the star?
11. Consider the information recorded in the chart. Which scenario(s) concluded with the planet crashing into the star?
12. Click
, recheck the boxes, and add a moon.
. Click
Describe the planet’s orbit.
Sketch the moon’s orbit. Why does it look like this?
13. Click
, recheck the boxes, and add a moon.
what’s indiated in the table below. Click
Mass
.
. Change the mass of the planet, sun or both according to
Effect on MOON and PLANET’s Orbit
Sun: 1.0
Planet: 2.0
Sun: 1.0
Planet: 0.5
Sun: 2.0
Planet: 1.0
Sun: 0.5
Planet: 1.0
Sun: 0.5
Planet: 0.5
Sun: 2.0
Planet: 2.0
14. Play around freely with these two selected (one at a time). Watch the sim with the objects in ‘normal’ masses; then play
around with other mass combinations. What happens pretty quickly in each sim?
15. Consider the sim. How does mass affect gravity?
16. What were some of the limitations of this simulation? Advantages?
Limitations
Advantages
Name _______________________________________________ Date ______________________ Hour ______________
Extra Credit: Gravity and Orbits Activity Part 2
1.
Go to: https://goo.gl/Qs8nLg (case sensitive)
2.
Choose “To Scale.”
3.
Select all boxes.
4.
Select.
5.
Click on
6.
Click
7.
and describe what you see.
, recheck the boxes, and change either the earth’s mass, the suns mass.
a.
Circle what you changed (Sun’s mass: greater or smaller OR Earth’s mass: greater or smaller)
b.
What happened to the orbit?
Click
, and select
and
. Click
and allow 365 days to pass. Describe what
happened to the planet and the moon’s orbits?
8.
In any of the sims, what happens when you turn gravity off and hit play?
9.
With
selected, what happens to the orbit when…
a.
You change the satellite mass?
b.
You change the planet’s mass?
10. In all the sims, what happens to the planet as things go around it? (Hint: make sure all boxes are checked!)