1. A Scaling of Our Solar System
Placing Planets
A Scaling of Our Solar System

3. ? Here’s a representation of the relative SIZES of planets
& sun in our solar system
(Which planet is biggest? First? Middle?)
The relative DISTANCES (spaces) shown between the planets, or to the sun, are not like our solar system.
Question: Let’s say we made a model of the sun that half a meter across and put it at the front of our classroom, how far back from this sun would earth be located?
In class we’ll have someone start near the sun and move slowly away.
Raise your hand when you think the relative distance to the sun is about right.
Sun (0.5m)
earth ?

4. Dist to Sun If sun 0.5 m In million km # suns (steps) Mercury 57.9
If sun 0.5 m then
Earth = m
= 0.4cm
= 4 mm
Dist to Sun
If sun 0.5 m
In million km
# suns (steps)
Mercury
57.9
41.4
Venus
108.2
77.3
Earth
149.6
106.9
Mars
227.9
162.8
Jupiter
778.3
555.9
Saturn
1,427
1019.3
Uranus
2,871.00
2050.7
Neptune
4,497.10
3212.2
Pluto
5,913
4223.6
A pencil eraser is about the right size (it’s just a little bit too big).
Start taking half-meter steps in the classroom. We need to get to [107] of these … we need more room!

5. 107 sun steps Earth’s size is tip of eraser Sun (0.5m) “sun steps”
pencil 1 2 3 4 5 6 7 8 9
Some ways to measure angles
“sun steps”
Each step 0.5 meters
[1] Start close to person holding model sun and take 107 sun steps.
[2] Measure
in terms of finger width(s) -- held at arm’s length -- the angle of the model sun (NOT the real sun). [Sun holder will need to rotate to be seen by everyone]
[3] Hold up eraser and try walking the orbit of the earth around the sun
Walk in orbit
Two fingers equals 2˚ & half finger is ½˚
(You should stop sometimes and check to check if finger [angle] measurement is the same).

6. Name: _______________ Date ________
[1] Pace 107 sun steps (0.5 m) out from sun.
[2] Mark location you get to on map
[3] Measure angle using finger
_____ ˚
Name: _______________ Date ________
[4] Walk in orbit holding Earth (eraser) facing sun. Stop sometimes to check angle (fingers).
50 m
Scale from Map

7. [2] What pattern do we see?
Class Results
[1] Each person or group should point to or place a mark where arrived after 107 steps.
[2] What pattern do we see?
How is it related to the orbit you walked?
50 m
(Do you think this image was taken recently?)
Scale from Map

8. Class Results Overall we measured: ______ ˚
Measurers
Angle (finger widths) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
Class Results
Two fingers equals 2˚ & half finger is ½˚
Overall we measured:
______ ˚

9. On a night with a full moon try and measure the angle in terms of finger widths at arm’s length.

10. (This is not related to what causes the phases of the moon).

11. Eclipses in History
Many ancient civilizations believed the occurrence of an eclipse was a demon eating the sun. They thought that the best way to get rid of the “demon” that was consuming their sun was to unite and make as much noise as possible to scare it away. At the first sight of an eclipse, everyone would immediately gather to bang drums and shout or scream as loudly as possible. The ancient Greeks believed that an eclipse was a sign of angry gods, therefore it was thought of as a bad omen.
Solar eclipses have even altered the course of human history. In 585 BCE the Lydians and Medes were engaged in battle in what is present-day Turkey. The Greek historian Herodotus recorded that at the height of a particularly fierce battle, darkness fell upon the land. Apparently the two armies waged a war close to the path of a solar eclipse. The armies took this as a sign and stopped fighting instantly, making peace with each other.

12. 3 m
100 sun steps
50 m
50 m
Use metric units
53 m
Scale from Map

13. 31 m
50 m
Mars
81 m
50 m

14. Which scale(s) do you think would be most useful for each planet
Which scale(s) do you think would be most useful for each planet? (Draw lines & there may be more than one).
Name ____________ Date _______
50 m
Mercury
21 m
Venus
39 m
Earth
53 m
Mars
81 m
Jupiter
278 m
Saturn
510 m
Uranus
1025 m
Neptune
1606 m
Pluto
2112 m
Each scale should have at least two lines to planets.
200 m
You may need to look at maps to decide which lines to draw.
500 m
1000 m
2000 m

15. Planet Orbit Mission
Each group will get one of the following maps. Each member will have his/her own copy.
Use multiple points for each planet to locate the orbits (circles) for at least two planets on the map you get.
Be sure to write the names and distances (in meters) for each planet. Make it clear which orbit (circle) goes with which planet
Each person in a group should make sure his/her map has the points and orbits.

16. Name _______________ Date ________
Which planets?
[1] _Earth__
(planet name)
___53 m___
(planet distance)
[2] ___________
_____________
[3] ___________ 1
Name _______________ Date ________
50 m

17. Name _______________ Date ________
Which planets?
[1] _________
(planet name)
__________
(planet distance)
[2] ___________
_____________
[3] ___________
Name _______________ Date ________
200 m

18. Name _______________ Date ________
Which planets?
[1] _________
(planet name)
___________
(planet distance)
[2] _________
[3] _________
Name _______________ Date ________
500 m

19. Name _______________ Date ________
Which planets?
[1] _________
(planet name)
___________
(planet distance)
[2] _________
[3] _________
Name _______________ Date ________
1000 m

20. Name _______________ Date ________
Which planets?
[1] _________
(planet name)
___________
(planet distance)
[2] _________
[3] _________
Name _______________ Date ________
2000 m

21. end

23. (copy to previous screen)
Radius of Earth Orbit
Radius of Mars Orbit