1. I. Protostellar Disk Forms
How Might The Solar System Have Formed?
Started as a solar nebula
Force (from nearby exploding star?) caused it to compress & collapse
I. Protostellar Disk Forms
Gravity pulls most of the mass towards center
Begins to rotate faster and faster
Flattens into a disk called a “protostellar disk”
Most matter in the disk is in center
Particles collide, releasing heat (friction)
II. Sun Forms
Temp. raises to 15,000,000° C
TEACHER NOTES below
Beforehand:
This ppt is basic text only, so do a Google image search and sprinkle images throughout the ppt. That’s why there’s extra room on the right side.
If you’re using this ppt along with your textbook line by line, the two probably won’t match up perfectly, so you’ll want to go through the ppt and change any wording above to match. Anything different will confuse your students (not good).
Print these ppt slides for yourself so know what what comes next as you’re doing this lesson
Materials per student: sheet of notebook paper; see opening demo for more materials
Opening demonstration (optional): give every 2 students a bowl with some water, a small piece of styrofoam, and a stirring rod. Have them pick the foam into small pieces, put them in the water, stir the water, and observe. The pieces will clump/gather until it’s all one mass spinning in the middle, just like we think our solar system formed! (If this is too much work for your, just have a student or two come up and do it as a demonstration in front of the class so they can at least see the process, which is exactly like what they’re getting ready to study.)
Procedure:
Have students open their books to page ______ (that describes the solar system formation)
Read the section aloud from book about protostellar disk aloud (all in one continuous read)
Do cause/effect chart for Part I above:
Re-read the same section sentence-by-sentence, stopping at every fact
Add to new facts to your chart
Notes:
Let them go: since this cause-and-effect chart follows a pattern of this happened, then this, then this…., let your students take over and start telling you the next thing to write down on the paper before it’s revealed. If they’re just copying what YOU say and put on the screen, there’s a lot less thinking going on inside their minds. If the most they can do on their own is just the next next or two before you check back in, then that’s still better than you doing all the work.
This extreme heat/pressure cause hydrogen atoms to fuse into helium atoms
Energy releases outward
This outward pressure is balanced by inward pull of gravity
Sun is born!

2. III.Planetesimals Form
Away from center, gravity causes particles to collect in a process called “accretion” (think “sticky collisons”)
Keep clumping and growing
III.Planetesimals Form
When they’re kilometers across they’re called “planetesimals”
The hot inner solar system is mostly metals and rock, while the cooler outer s.s. mostly gas and ice
IV. Planets Form
Accretion in the inner and outer s.s. continues, forming the planets
(On the back side)