BACKGROUND:
The discovery of the planets took place over thousands
of years. It was a widespread belief until the 1700's that everything
revolved around the Earth. Early philosophers and scientists observed that a
few bright objects in the sky did not keep their positions like the stars.
They also observed that these objects all moved in a narrow band of the sky
, which is now called the zodiac. These objects eventually came to be called
planets, from the Greek word for "wanderer".
The Greeks and Romans associated the planets with
their gods. Mercury, which is the quickest of all the planets, was named for
the Roman fleet footed, fast running god. Venus was named after the goddess
of love, because it shined so brightly before sunrise and sunset. Mars was
named for the god of war, because it glows red and appears majestically high
in the night sky. Jupiter, the largest planet, was given the name of the
king of gods. Saturn appeared to move slowly in the sky, so it was named for
the great grandfather of the gods. These were the planets that were apparent to
early people. The other planets: Uranus, Neptune, and Pluto, were not
discovered until after the telescope was invented.
Some historians have speculated that the 5 moving
planets, plus the Sun and Moon may account for the special regard many
cultures have for the number 7. In Europe, this became the number of days in
the week. Sunday is the Sun's day, Monday is the Moon's day, and Saturday is
Saturn' day. The other four days are named for the Viking gods, who were
similar to the Greek and Roman gods. Tuesday was named for the god Tiw who
was the same as the god Mars. Wednesday was named after Woden or the Greek's
Mercury; Thursday is for Thor or Jupiter and Friday is for Freya, who was
equivalent to Venus.
PROCEDURE:
- You may wish to review the basic characteristics of
the planets with the class. At this point, the students should be able
to name the planets in order of distance from the Sun, and distinguish
between the terrestrial and gas giant planets. Use the information
charts below to guide your comments.
PLANETARY INFORMATION
DATA CHART I.
|
planet |
diameter |
low surface temp CE |
high surface temp CE |
distance from the Sun (km) |
satellites |
|
MERCURY |
4,880 |
-170 |
+400 |
0.0579 x 109 |
0 |
|
VENUS |
12,100 |
? |
+480 |
0.1082 x 109 |
0 |
|
EARTH |
12,740 |
-53 |
+50 |
0.1496 x 109 |
1 |
|
MARS |
6,794 |
-127 |
-29 |
0.2279 x 109 |
2 |
|
JUPITER |
143,200 |
? |
- 148 |
0.7783 x 109 |
>63 |
|
SATURN |
120,000 |
? |
-178 |
1.427 x 109 |
>47 |
|
URANUS |
51,800 |
? |
-214 |
2.87 x 109 |
>27 |
|
NEPTUNE |
49,500 |
? |
-218 |
4.497 x 109 |
>13 |
|
PLUTO |
2,500 |
? |
-330? |
5.9 x 109 |
>3 |
Note that the temperatures for Jupiter
through Neptune are average surface temperatures.
DATA CHART II.
|
planet |
mass of
planet |
tilt of
axis |
revolution |
rotation |
eccentricity |
rings |
|
MERCURY |
.054 |
|
88 days |
59 days |
.21 |
0 |
|
VENUS |
.82 |
|
224.7 days |
243 days |
.01 |
0 |
|
EARTH |
1 |
23 |
365 days |
24 hrs |
.02 |
0 |
|
MARS |
.11 |
24 |
687 days |
24 hrs |
.09 |
0 |
|
JUPITER |
318 |
3 |
12 years |
10 hrs |
.05 |
1 |
|
SATURN |
95 |
27 |
29 years |
11 hrs |
.06 |
7 |
|
URANUS |
15 |
98 |
84 years |
15.5 hrs |
.05 |
10 |
|
NEPTUNE |
17 |
50 |
165 years |
16 hrs |
.01 |
4 |
|
PLUTO |
.9(?) |
? |
248 years |
6.5 days |
.25 |
0 |
- In this activity, students determine the relative
distances of the planets from the Sun, and show these in a drawing. The
students are asked to make the numbers proportional to real Solar System
distances, so that they can make their drawings accurate. The model
works best if the distances are converted into centimeters. The students
may struggle to figure this out; but give them guidance as appropriate.
You may want the students to work in groups of 2 or 3 to try and figure
the problem out collectively. Remember to have the students start from
the Sun and to round off the numbers.
First go over that you drop the 109 km
because when you compare things that are the same, and they all contain
the number you can disregard it. Have the students cross out all 109 km. Then look at the other numbers and have them round them off.
You may have to reason with them and give them the rounded answers as
listed below.
If students are not familiar with a metric ruler
you may want to go over the fundamentals of centimeters and millimeters.
It is easiest to use mm instead of cm, especially if you want it to fit
on one page. However, if you have longer paper (i.e., butcher paper), cm
will not be a problem. You could also make this fit on one sheet, by
having the students divide these numbers by 2. If students cannot do
division, do it with them and give them the answer. This helps them to
understand why they should learn division.
If the students use centimeters, the drawing will
not fit on one sheet of paper.
ANSWERS: [2 sheet
solution] 0.6 cm or 6 mm (Mercury); 1 cm (Venus); 1.5 cm (Earth); 2.3 cm
(Mars); 7.8 cm (Jupiter); 14 cm (Saturn); 29 cm (Uranus); 45 cm (Neptune);
59 cm (Pluto).
|
