Inquiry Activity 1:
Time frame:   Two  class periods

Objectives:
Students will begin to share what they do know about the solar system and express their own explanations for how it may have formed.  Students will perform a simulation of the formation of the solar system using pepper and water.  Use appropriate software to obtain information on the planets.

Materials:
Overhead projector, transparency of the solar system, a poster of the solar system, water, finely ground pepper in a shaker, a flat-bottomed container 3’-5’ across (a cottage cheese contained or a bowl) for every lab station, 1 stirring implement, such as a popsicle stick or a spoon for each lab station.
Teaching Tips:
Day 1
Show students the Our Solar System overhead transparency (can be found on documents page) and/or poster of the solar system.  Tell them to take turns for  a couple of minutes sharing with a partner what they think they know about the solar system.  Then, ask them to share some of their ideas with the whole class.  During the discussion, you may choose to restrict the discussion to the information your students bring up.  You may also choose to supplement their knowledge with some of the following information: 

   *There are nine known planets:  Mercury, Venus, Earth, Mars, 
     Jupiter, Saturn, Uranus, Neptune, and Pluto.

   *There is an asteroid belt between Mars and Jupiter.  Scientists 
     have found other objects like asteroids in a belt beyond Pluto.
     Some think Pluto is not a planet, but a large asteroid from that 
     belt.

   *Except for Pluto, the planets lie essentially on the same plane.
     The orbit of Pluto, some asteroids, and most Oort Cloud comets
     are in different planes.

   *Except for Pluto, the orbits are nearly circular.  Pluto's orbit is 
     more oval, occasionally bringing it closer to the Sun than 
     Neptune.

   *All the planets circle the Sun in the same direction - 
     counterclockwise, if viewed from above the North pole.

   *The four planets closest to the Sun (Mercury, Venus, Earth, and
     Mars) are all rocky planets, and are called the terrestrial planets. 

   *The four planet beyond Mars (Jupiter, Saturn, Uranus, and
     Neptune) all have solid cores covered by huge cold atmospheres 
     of gases, and are called the gas giants.  They are much farther
     apart than the rocky planets.

   *No one know why Pluto, a very small rocky and icy planet, is just 
     beyond the gas giant zone.

   *It is generally accepted that our Sun is also surrounded by a vast 
     cloud of comets (the Oort cloud).  Most of these comets are far
     beyond the orbit of Pluto.

   *Scientists estimate that it took about 100 million years for the
     solar system to form.  No one know exactly how it formed, but 
     scientists have come up with possible explanations and theories.

Challenge your students to come up with their own explanations of how the solar system formed.  Let them discuss these in small groups for about 3-5 minutes.  Allow them to illustrate their ideas on paper if they find it helpful.

Day 2
Tell your students that they will use water and pepper as a model  for the formation of the solar system.  The pepper will represent the material from which the solar system formed.  The water will represent empty space.
   1. Pass out containers, pepper shakers, and stirring implements.
       Have students fill them with 3 -4 cm of  water.
   2. Next have them put 2 good shakes of pepper into their container.
       Explain to them that they are putting a thin scattering of “gas and
       dust” into their containers of “empty space”.
   3. Tell them that gravity pulls the gas and dust together into a
       swirling mass.  Have a student at each station give three of four
       quick counterclockwise stirs to the water, then stop stirring and
       observe what happens.  Let them know that they will soon repeat
       the activity, so that eventually everyone at their station will get a
       chance to stir.
   4. Have students discuss what they see in their lab groups, and then 
       call on students to describe how the system of water and pepper 
       evolves.  [They should note that most of the pepper gravitates 
       toward the middle and forms a large clump.  Some of the pepper 
       grains do not join the clump, but swirl around at various distances 
       from the center.]
   5. Ask the students how this might represent the formation of the 
       planets.  If they do not mention it themselves, tell them that the
       clump in the center represents the Sun, and the pieces orbiting it
       represent the planets.  Tell them that in this model other forces
       actually drew pepper grains together in the center, but that in the
       real solar system it was gravity.
   6. The students can easily disturb the system with their stirring
       implement and form pepper into a disorderly cloud again.  Give
       them a few minutes to form, un-form, and re-form their solar 
       systems several times.  Encourage them to report any new
       observations they may make.

Inquiry Activity 2: 
Use software for a Field trip to the planets. Suggested software is by Sunburst, A Field Trip to the Sky.
Objective:  to familiarize the students with the nine planets, the Moon, or the Sun.
Teaching Tips:
Allow the students to spend a class period just browsing through the software and playing the Solar System game.  They can then use this software as part of the research they will do in the application part of this unit of practice.