Placing Planets

A Scaling of Our Solar System

http://www.enchantedlearning.com/subjects/astronomy/planets/

Here’s a representationof the relativeSIZES 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?

earth

Sun (0.5m

) ?

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.

If sun 0.5 m thenEarth = 0.004 m

= 0.4cm= 4 mm

Dist to Sun If sun 0.5 mIn million km # suns (steps)

Mercury 57.9 41.4Venus 108.2 77.3Earth 149.6 106.9Mars 227.9 162.8Jupiter 778.3 555.9Saturn 1,427 1019.3Uranus 2,871.00 2050.7Neptune 4,497.10 3212.2Pluto 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 106.9 [107] of these … we need more room!

Earth’s size istip of eraser

Sun (0.5m)

0.5m 0.5m 0.5m 0.5m 0.5m 0.5m 0.5m 0.5m

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

Two fingers equals 2˚ & half finger is ½˚

1 2 3 4 5 6 7 8 9“sun steps”

Some ways to measure angles

(You should stop sometimes and check to check if finger [angle] measurement is the same).

107 sun steps

pencil

Scale from Map50 m

[1] Pace 107 sun steps (0.5 m) out from sun.

[2] Mark location you get to on map

[3] Measure angle using finger

_____ ˚

[4] Walk in orbit holding Earth (eraser) facing sun. Stop sometimes to check angle (fingers).

Nam

e:

____

____

____

___

Dat

e __

____

__

Scale from Map50 m

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?

(Do you think this image was taken recently?)

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

Two fingers equals 2˚ & half finger is ½˚

Class Results

Overall we measured:

______ ˚

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

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

http://www.mathopenref.com/subtend.html

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.

Eclipses in History

http://www.timeanddate.com/eclipse/solar-eclipse-history.html

50 mScale from Map

Use metric units50 m

3 m

100 sun steps

53 m

50 m

31 m

81 mMars 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

500 m

200 m

1000 m

2000 m

Which scale(s) do you think would be most useful for each planet? (Draw lines & there may be more than one).

Name ____________ Date _______

50 mEach scale should have at least two lines to planets.

You may need to look at maps to decide which lines to draw.

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.

Which planets?

[1] _Earth__ (planet name)

___53 m___(planet distance)

[2] ___________ (planet name)

_____________(planet distance)

[3] ___________ (planet name)

_____________(planet distance)

1

50 mName _______________ Date ________

Which planets?

[1] _________ (planet name)

__________(planet distance)

[2] ___________ (planet name)

_____________(planet distance)

[3] ___________ (planet name)

_____________(planet distance)

Name _______________ Date ________200 m

Which planets?

[1] _________ (planet name)

___________(planet distance)

[2] _________ (planet name)

___________(planet distance)

[3] _________ (planet name)

___________(planet distance)

Name _______________ Date ________500 m

Which planets?

[1] _________ (planet name)

___________(planet distance)

[2] _________ (planet name)

___________(planet distance)

[3] _________ (planet name)

___________(planet distance)

Name _______________ Date ________1000 m

Which planets?

[1] _________ (planet name)

___________(planet distance)

[2] _________ (planet name)

___________(planet distance)

[3] _________ (planet name)

___________(planet distance)

Name _______________ Date ________2000 m

end

Radius of Earth Orbit

Radius of Mars Orbit

(copy to previous screen)

http://ase.tufts.edu/cosmos/view_picture.asp?id=294