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!

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)