Download The Solar System Activities Outline

The Solar System Activities Outline
Students will need their textbook at every class!
Suggested
no. of
lessons
Part,
combine
with mind
map
1
Link on web page
What do you already know?
The solar system mind-map.
1
What are orbits?
1 or 2
1
1
1 or 2
Build a Solar System experiment
an actual model
virtually (on-line)
Compare the size and distance from the
sun of other planets with Earth
Sun facts
Simulating gravity experiment.
The Interplanetary Space Tour Diary
WebQuest
Asteroids, comets and meteorites
 Comet experiment (teacher demo)
 Meteorite experiments
1
What have you learned?
none
1 or 2
1
1
4?
Comments/Notes
Overview only at this stage
to focus
Web, computer and
practical activity
Practical activity
Homework activity
Practical activity
This will take several
lessons
Optional
Practical activity Choose 1
of those outlined below
(or both)
Studying Orbits
Aim. The students will be able to:
Explain how to draw an ellipse
Relate the shape of an ellipse to the shape of the planets’ orbits around the sun
A.
First, let’s draw some ellipses using string, pins pencil and paper. 1
You will need:
Piece of corrugated cardboard or stiff card at least 25 centimetres
(10 inches) square
String
Ruler (metric or English units)
Pencil
2 straight pins or push pins
1.
2.
Tie a 20-centimeter (8-inch) length of string into a loop.
Push a pin into a piece of cardboard. Place the
loop of string around the pin.
Use a pencil inside the loop to trace out a shape as you pull the loop tight.
Place a second pin 5 cm (2 in) from the first pin.
With the loop of string enclosing both pins, trace
another shape with the pencil.
This shape is called an ellipse. How is this shape different from the first shape?
A circle has a single center, but an ellipse has two centers, called foci (FO-sigh). The pins represent
the foci of the ellipse you have drawn.
3.
Move one of the foci so it is 8 cm (3 in) from the
other one.
Trace a loop with the pencil. How did
the shape of the ellipse change?
The amount of flattening of the ellipse is called its eccentricity. A circle is a special kind of ellipse with no
flattening, so we say it has an eccentricity of 0 (zero). An ellipse that is so flat it looks almost like a straight
line has an eccentricity of almost 1.
1From
an article Originally published in The Technology Teacher, April 1999, by the International Technology
Education Association, and published on the net by NASA at http://stardust.jpl.nasa.gov/classroom/guides.html
The orbit of anything that orbits the Sun has two foci, with the Sun at one and empty space at the other. As a
comet comes near the Sun, the Sun’s gravitational pull speeds it up until it is going fastest when closest to
the Sun. The comet’s path is bent by the increasing pull of the Sun’s gravity until it swings around the Sun
and heads back into deep space. The comet’s momentum sends it far into space, although it slows down
because of the Sun’s gravitational pull. Sometimes, comets come so close to the Sun, they just crash into it,
instead of swinging around it. Well, they don’t really “crash,” because all the ice has evaporated long before
they actually hit the Sun.
Nearby planets, especially the larger planets like Jupiter and Saturn can disturb comets’ orbits. These giant
bodies have enough gravitational pull to change a comet’s orbit dramatically, flinging it in toward the Sun,
into a planet, or out farther into deep space never to return. Comet Shoemaker-Levy 9 was captured and
broken up by the huge gravitational forces of Jupiter, and ended up crashing into the planet in 1994.
Scientists now believe that Jupiter’s gravity has helped deflect many comets away from Earth since its
formation, helping protect our fragile environment enough to allow life to evolve and flourish over a long
period.
Comets’ orbits differ from those of planets not only in their shape (eccentricity), but also in their orientation.
All planets’ orbits lie very close to an imaginary flat plane called the ecliptic. In fact, all planets even orbit
the Sun in the same direction. The orbits of comets, on the other hand, are tilted at random angles to the
ecliptic.
If we have the students draw several ellipses on the same piece of paper it may help
them get the idea of all the orbits except Pluto being in the same plane.
B.
Lets draw some orbits using Paint
(The teacher should practice this activity so they can lead the students through it.)
 Open Paint, click on Images  Attributes and set the picture to be 640 x 480
pixels.
 Click on the Ellipse tool, and then hold down the Shift key while to draw a circle
in the middle of the page. This will be your sun. Colour it orange if you wish.
 Now draw some ellipses around the “sun”. You can change your line colour and
thickness if you wish.
 Experiment with the “flatness” or eccentricity of the ellipses.
 Next, move your curser to the top or bottom of the page away from your previous
drawing.
 Draw a long flat ellipse that you will be able to fit a selection box around.
 Select this ellipse, and click on Image  Stretch/Skew.
 Skew it 40 degrees to the vertical and drag the skewed ellipse over the others.
Be Sure to have the paste tool as,” show background”

This skewed ellipse can mimic either the orbit of Pluto, or if you draw a really flat
ellipse, the orbit of comets.