Solar System Model

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Contents 1 Objectives 2 Pre-event preparations 3 Presentation set-up 4 Actual vs. scale sizes and distances 5 Delivering the presentation 6 Variations 7 Related references

The inspiration for this presentation is the "Relative Size of the Planets" model developed by the Perkins Observatory. For details, please refer to www.perkins-observatory.org/educational files/sizesofplanets.pdf.

[edit] Objectives

1. Introduce a frame of reference for visitors with which they can easily relate (Jupiter as a basketball, distances in feet and miles, etc.)
2. Help visitors appreciate the size of the other planets in relation to Earth.
3. Help visitors comprehend the physical dimensions of the solar system (distance from Sun, distances between the planets).

[edit] Pre-event preparations

None.

[edit] Presentation set-up

1. Retrieve the solar system model presentation materials from Baby Bear. The inventory of items include 11 balls, marbles and beads of various sizes representing the various planets. From largest to smallest they are:
   • Basketball = Jupiter
   • Soccer ball (size 4) = Saturn
   • Softball = Neptune
   • Softball = Uranus
   • Wooden bead = Earth
   • Wooden bead = Venus
   • Small red marble = Mars
   • Small dark purple bead = Mercury
   • Small white bead = Moon
   • Smallest white bead = Pluto
     
     
2. Each solar system body has a card containing its relevant physical characteristics. There is also a 100m measuring tape, and maps of the surrounding area with the solar system's scale superimposed on them.Set-out the planets and Moon next to their respective cards (see photo at top of page).

[edit] Actual vs. scale sizes and distances

Object	Act. Dia. (miles)	Act. Dia. (km)	Scale Dia. (mm)	Scale Dia. (inches)	Act. Dist. (miles)	Act. Dist. (km)	Scale Dist. (meters)	Scale Dist. (feet)	Scale Dist. (miles)	Satellites
Sun	865,000	1,395,161	2,372	93.4
Mercury	3,024	4,878	8	0.3	36,187,500	57,900,000	98	325	0.06	0
Venus	7,504	12,104	21	0.8	67,625,000	108,200,000	184	607	0.11	0
Earth	7,909	12,756	22	0.9	93,500,000	149,600,000	254	839	0.16	1
Moon	2,155	3,476	6	0.2	240,250	384,400	1	2	0.00
Mars	4,213	6,795	12	0.5	142,437,500	227,900,000	387	1,279	0.24	2
Jupiter	88,651	142,985	243	9.6	486,437,500	778,300,000	1,323	4,366	0.83	62
Saturn	74,733	120,537	205	8.1	893,375,000	1,429,400,000	2,430	8,019	1.52	60
Saturn's Rings	372,000	600,000	1,020	40.2
Uranus	31,694	51,119	87	3.4	1,796,875,000	2,875,000,000	4,888	16,129	3.05	27
Neptune	31,334	50,538	86	3.4	2,815,250,000	4,504,400,000	7,657	25,270	4.79	13
Pluto	1,427	2,320	4	0.2	3,697,375,000	5,915,800,000	10,057	33,188	6.29	3

[edit] Delivering the presentation

1. When starting the presentation, gather a group of people and ask them if they'd like a tour of the solar system.
2. Pick up the Earth and associated placard from the table, and ask each person to "pick their favorite planet" from the remaining planets.
3. Take the group, with their planets and placards out to the plaza. Bring the area maps and the storage container for the model. Form the group into an 8' diameter circle (this circle will represent the Sun throughout the presentation.
4. Begin by introducing the scale of the model and its purpose:
   • Scale model based on Jupiter represented by basketball:
     • 1 basketball diameter = 88,600 miles in diameter
     • Jupiter is about 11 times the size of the Earth
     • The Sun is a little more than 9 times larger than Jupiter, at 8 feet in diameter
     • The 93 million mile distance from the Sun to the Earth is 839 feet -- just short of three football fields
   • Help them understand:
     • The solar system is BIG
     • There are vast amounts of 'empty space' between the planets
     • The general insignificance of the Earth when compared to the Sun and larger planets
5. Continue by describing the size of the sun, relative to the size of the terrace, or the metal semicircular section of the wall above Baby Bear's door.
6. Next, ask for the person holding Mercury to bring it forward. Describe its actual physical size, and contrast the size of the bead with the size of the scale sun and the Earth. Next, describe its actual distance and then its scale distance. Point out some object or location at the approximate scale distance. Share an interesting fact or two regarding Mercury (see notes on the planet's card for details). Have the person place the planet down on the "Sun" and return to their place in the circle.
7. Continue in a similar fashion with the next three planets (Venus, Earth and Mars). As you finish with each planet, place it by the others, in sequence.
   • When demonstrating the Earth include the Moon. Take time to show the relative distance between the Earth and the Moon.
8. Before proceeding to the gas giants and Pluto, allow people a moment to reorient themselves while you hand out the maps describing the scale locations of the remaining planets.
9. Continue with the gas planets and Pluto, making reference to map landmarks for each.
   • When demonstrating Jupiter, compare the scale Earth to the size of the Great Red Spot.
   • When demonstrating Saturn, compare the scale Earth to its rings (47x the Earth's diamter)
10. Once the demonstration is complete, ask for questions.
11. Gather up the model and carry it back into the observatory using the storage box. Set the planets and Moon out again as a static display.

[edit] Variations

• Should weather preclude delivering the presentation on the terrace, it can be done indoors, using the semi-circular metal arch above Baby Bear's door to represent the Sun.
• Discuss recent discoveries regarding extra-solar planetary systems, including naked-eye stars with planets that are visible the evening of the presentation.

[edit] Related references

• "Relative Size of the Planets" model .pdf by the Perkins Observatory.
• Planetary Satellite Discovery Circumstances from JPL. Lists current satellite counts for each planet and information regarding discovery circumstances.
• NASA's PlanetQuest Exoplanet Exploration program.