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 text only, so do a Google image search and sprinkle relevant images throughout the ppt. That’s what the extra room on the right side is for.
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 this ppt and change any wording above to match what your book says. Anything different will confuse your students (not good). If your book doesn’t cover this, then just go with the ppt as-is.
Print these ppt slides for yourself so know what what comes next as you’re doing this lesson.
Materials per student: sheet of lined notebook paper
Opening demonstration (optional): Give every 2 students a bowl with some water in it; also a small piece of styrofoam, and a stirring rod. Have them pick the foam into small pieces, put those pieces in the water, stir, 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.)
Procedure:
Have students open their books to page ______ that describes the solar system formation. (If this is not in your book at all, just use the PowerPoint to lead the activity, and have students write down the steps when they’re shown.)
Read the section aloud from book about the Protostellar Disk, all in one continuous read.
Do cause/effect chart for Part I above:
Re-read the Protostellar Disk section sentence-by-sentence, stopping at every fact.
Add new facts to your chart as you read.
Continue doing the same with the 3 other parts.
Notes:
Since this cause-and-effect chart follows a pattern (first 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 not much thinking going on inside their minds.
Beforehand, go through and write all this out on a sheet of paper for yourself. You’ll be surprised at how much better you communicate during the lesson.
Thanks for using this lesson
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)