Teacher's Guide for:

Planet Search

OBJECTIVES:

• To find the current planets in our night sky and see why they were called "wanderers."
• To investigate the planets, comets, and other objects in our Solar System
• To appreciate Earth's place among the other planets
• To speculate as to how our Solar System was formed, given the evidence.

This show conforms to the following state science standards:  12.F.1a, 12.F.1b, 12.F.2a, 12.F.2b, 12.F.2c, 12.F.3b, 12.D.5b, 12.F.2a

 Planet Search takes the student on a trek through the Solar System. During 40 minutes of live and recorded presentation, all nine planets are explored as are the Sun, meteors, and comets. Not only do we travel in space, but through time as well, as we journey to see the Solar System accreting from an interstellar cloud of gas. Scars of this process are examined by studying our Earth's neighbor in space: our own Moon.

1. What is a "planet?" How can you tell the difference between stars and planets in the sky?
2. Where can you find the planets in the sky? 
3. What makes our Earth a special planet? What does it have that no other planet has? [liquid water]
4. If you were to build a space ship, what other planet would you want to visit? Why?

1. Construct a simple model illustrating the distance between the Earth and the Moon. Most classrooms or libraries are equipped with a globe of the Earth. If this globe is roughly 12 inches in diameter then the Moon's relative size would be the size of a baseball. Have students note that the Moon's diameter is a bit smaller than the width of the United States. Now the Moon must be placed at the correct distance from the Earth, which is about 30 feet on this scale. Discuss how long it took our Apollo astronauts to travel this distance. 
2. The tremendous distances in our solar system may be visualized in the classroom by constructing a model from simple home items. In order to fit the model within a room we have divided the actual distances by a factor of 450.
    

   Object	Diameter	Scale Object	Scale Distance
   Sun	864,000 miles	38-inch circle	.
   Mercury	3,100 miles	brass BB	3-1/8 inches
   Venus	7,550 miles	marble	6-3/4 inches
   Earth	7,927 miles	marble	9-1/4 inches
   Mars	4,200 miles	1/4" bead	14-1/8 inches
   Jupiter	88,900 miles	softball	48-1/2 inches
   Saturn	75,200 miles	baseball	89-1/4 inches
   Uranus	29,200 miles	golf ball	177-3/4 inches
   Neptune	28,000 miles	ping pong ball	279-3/4 inches
   Pluto	1,500 miles	grain of sand	367 inches
   Oort  Cloud	7-1/3 miles	.	.
   Alpha Centauri  (nearest star)	39-1/2miles	.	.

   After completing the model, you may discuss the following issues: 

   1. The elliptical orbit of Pluto brings it inside the orbit of Neptune for 20 years of Pluto's 248 year orbit about the Sun. Where is Pluto now? Which is the farther planet? 
   2. Given these distances illustrate where the Voyager 2 spacecraft is at present after passing Neptune in August of 1989, discuss the distance it has covered since its launch in 1977. 
   3. Introduce the laws of Kepler and Newton. Discuss the fact that the closer a planet is to the Sun, the shorter time it takes for that planet to make a complete revolution. 
3. Discuss the school year for the mythical schools on the planet Uranus. Remember that with the extreme tilt of the axis of the planet, summers and winters are both 20 years in length. How would the school year be structured? How long would it take to graduate?
4. The amount of gravity a planet possesses depends on its mass. A person's weight depends not only on the amount of mass the person has but also on the amount of gravity. Therefore a person will weigh less on a planet that is smaller than the Earth and weigh more on a planet that is larger than the Earth. This can be illustrated by using a simple can of soda pop. On Earth this 16-ounce can weighs 386 grams. Take several other empty soda cans and fill them with material (lead pellets, marbles, rock, etc.) until they weigh the following amounts for each planet. This is how much a full can would weigh if you were to take it to the planet:

   Body	grams
   Sun	10,808
   Mercury	150
   Venus	339
   Earth	386
   Mars	147
   Jupiter	903
   Saturn	357
   Uranus	307
   Neptune	434
   Pluto	170

INTERNET RESOURCES:

Solar system tour: http://seds.lpl.arizona.edu/pub/billa/tnp/nineplanets.html
Peoria's scale solar system: http://www.bradley.edu/las/phy/solar_system.html
Planetary photojournal: http://www-pdsimage.jpl.nasa.gov/pia
Comet news: http://encke.jpl.nasa.gov/eph.html
Views of the Solar System: http://bang.lanl.gov/solarsys
Also check the homepages of current space missions: http://www.jpl.nasa.gov
Sky & Telescope magazine (for current planets):  http://SkyandTelescope.com

Why not visit the Staerkel Planetarium's scale model solar system while you're visiting!