MC

6th Grade

Standard: 03

Objective:  03.  Describe the forces that keep objects in orbit around the sun.

ILO:

 

 

What two forces hold the planet in their orbits around the sun?

               a.  gravity, forward velocity

               b.  gravity, mass

               c.  acceleration, velocity

               d.  attraction, speed

 

Correct Answer:  a

 

MC

6th Grade

Standard: 03

Objective:  03.  Describe the forces that keep objects in orbit around the sun.

ILO:

 

 

What would happen to Earth if it started going faster around the sun?

               a.  It would fall into the sun.

               b.  It would travel away from the sun.

               c.  ItsÍ gravity would decrease.

               d.  ItsÍ gravity would increase.

 

Correct Answer:  b

 

MC

6th Grade

Standard: 03

Objective:  03.  Describe the forces that keep objects in orbit around the sun.

ILO:

 

 

Without gravity, what would be the shape of the solar system?

               a.  Planets would revolve in perfect circles.

               b.  There would be no solar system.

               c.  PlanetsÍ orbits would cross.

               d.  All planets would be in the same orbit.

 

Correct Answer:  b

 

 

 

 

 

 

 

MC

6th Grade

Standard: 03

Objective:  03.  Describe the forces that keep objects in orbit around the sun.

ILO:

 

 

Compare the gravity on the Earth and the moon to determine which statement is correct.

               a.  The moon orbits Earth because they have an equal gravitational pull on each other.

b.  The moon and Earth do not collide because the gravitational force of each pushes them apart.

c.  The gravity of the Earth and the moon pulls them together, but EarthÍs gravity is greater because it has more mass.

d.  The Earth and moon do not collide because the Earth has greater mass and, therefore, greater gravity than the moon and pushes it away.

 

Correct Answer:  c

 

MC

6th Grade

Standard: 03

Objective:  03.  Describe the forces that keep objects in orbit around the sun.

ILO:

 

 

Which object has the most gravity?

               a.  Earth

               b.  moon

               c.  Jupiter

               d.  sun

 

Correct Answer:  d

 

E

6th Grade

Standard: 03

Objective:  03.  Describe the forces that keep objects in orbit around the sun.

ILO:

 

 

How are the orbits of Earth around the sun and the orbit of the moon around the Earth alike?

 

Correct Answer:

Both rely on the greater gravitational pull of the more massive object and their own forward motion to match and keep them in orbit.

 

 

 

 

 

 

 

E

6th Grade

Standard: 03

Objective:  03.  Describe the forces that keep objects in orbit around the sun.

ILO:

 

 

How is spinning a weight tied to a string around your head similar to the orbit of a planet around the sun?

 

Correct Answer:

The spinning speed is the same as the velocity of a moving planet, the string is like gravity holding it in orbit.

 

P

6th Grade

Standard: 03

Objective:  03.  Describe the forces that keep objects in orbit around the sun.

ILO:

 

 

Staying in Orbit

 

Activity Description:

In this activity students will model the forces that keep planets in orbit and discover relationships between mass, distance, and velocity in an orbit.

 

Materials:

1 meter (and a little more for tying the knots) of string per group (4 students)  a meter stick, 4 large metal washers, clock with second hand or stopwatch, student sheet (see below)

 

Time Needed:

50 minutes

 

Teacher Background:

Objects stay in stable orbits when the gravity between them and a larger body (like the sun) and their own forward velocity, match.  The distance a planet is from the sun affects the gravitational attraction.  If preferred, this can be done as a demonstration with one student swinging the ñplanetî and the class counting and timing the swings.

 

Procedure:

1.  Explain to students that they will be investigating the forces that keep planets in orbit and read the introduction and procedures to the activity.

2.  Allow groups to gather their materials.  Remind them to stay far enough apart that the swinging washers do not hit anyone.

3.  Allow time for students to collect data.

4.  As a class, discuss data and draw conclusions.

5.  Allow students time to answer questions on student sheet.

 

 

Scoring Guide:

1.  Students make predictionƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒ.3 pts

2.  Students design their own testƒƒƒƒƒƒƒƒƒƒƒƒƒƒƒ10 pts

3.  Students collect and record dataƒƒƒƒƒƒƒƒƒƒƒƒƒƒ15 pts

4.  Students correctly answer questionsƒƒƒƒƒƒƒƒƒƒƒƒ.5 pts

5.  Students write specific and pertinent conclusionƒƒƒƒƒƒƒ3 pts

 

Correct Answers:

1.  Shortening the string increases the speed and shortens the revolution time.

2.  The Inner planets have the shortest revolutions

3.  Increasing the mass shortens increases speed needed and shortens revolution time.

4.  The larger objects require more speed in forward motion to keep from falling.

5.  Answers will vary. 

 

 

Student Sheet

 

Staying in Orbit

 

Name_______________________

 

Introduction: 

In this activity you will investigate the factors that affect the revolution of planets around the sun.  We will use string for ñgravityî and washers for ñplanetsî.

 

Materials:

1 meter of string, a meter stick, 4 large metal washers, clock with second hand or stopwatch

 

Procedure:

1.  Tie two washers on the end of your string.  Have a student hold the end of the string and swing it over their head.  Swing it only fast enough to keep it in ñorbitî.  Make sure you will not hit anyone with the washers.

2.  Have one student count the number of revolutions the washers take in 10 seconds.  One student needs to time while the other counts.  Do this twice and average your results. Record your data on the data table.

3.  Fold the string in two and hold it in the middle (at the 50 cm) mark.  Repeat the counting for 10seconds.  Do this twice and average your results. Record your data on the data table.

4.  Put two more washers on the string and repeat #2 and #3. 

5.  Think of another different test you can do concerning orbits with the string and washers.  Write down here what you will do:

            a.

 

            b.

 

Record this data also.

6.  Answer the questions when you are done.

 

Prediction: 

(Which combination of string and washers will go fastest?)

 

 

Data:

Experiment

First test

Second test

Average

100 cm, 2 washers

 

 

 

50 cm, 2 washers

 

 

 

100 cm, 4 washers

 

 

 

50 cm, 4 washers

 

 

 

Your experiment

 

 

 

 

 

 

Questions:

1.  What effect did making the orbit smaller (shortening the string) have on the speed of the washers and time it took to make an orbit (revolution)?

 

 

2.  Which planets in the solar system have the shortest revolution time?

 

3.  How does increasing the weight of the ñplanetî affect itsÍ revolution?

 

 

4.  Why?

 

 

5.  What did your experiment show?

 

 

Conclusion: