High school students were to read Foundations of Astronomy section 10-3 Gas-Star-Gas cycle and Ch 11 Star structure & formation and/or watch the videos for Big History Project Unit 3.0 and the following Crash Course Astronomy videos.
As students arrived for class I had them fill out a moon journal page, starting with today’s date and then stepping outside to view the moon and sketch what they saw. I also had my telescope set up so students could take a closer look. I told the students to keep the observation log on their fridge or somewhere they will see it and remember to step out and observe the moon each day.
Once everyone had their first moon observation, I gave a slideshow on star formation, different type of nebula and the life cycle of stars. You can find a slideshow on the Lives of Stars at the Night Sky Network. This site has a ton of fantastic resources for astronomy, just use the search window to find activities, slideshows, posters, etc for your topic.
After the slideshow, we did the Nuclear Fusion in Stars activity, also from the Night Sky Network. In this activity we had a bowl of mini-marshmallows represents protons (Hydrogen nuclei) and a bowl of short pasta representing gamma ray photons. I asked each student to grab two protons (marshmallows) and asked them what they knew about protons – they have positive charge. So do two protons want to be close to each other? No! They repel each other. For two protons to undergo nuclear fusion they must be traveling very fast and collide just right, and when they do they release energy in the form of gamma radiation. At this point everyone squishes their two marshmallows together and grabs a piece of pasta to represent the gamma photon that was released. We’ve now made a helium atom (2 protons) and need to make two more. One you have 3 helium atoms you squish two of them together, producing another gamma photon and then the last helium nucleus fuses with the 4 protons so that you now have 6 protons in your nucleus, which means you made carbon. I mentioned that we didn’t make lithium (3 protons) because its not stable and falls apart almost immediately, which is why stars are mostly H and He. Protons do not undergo nuclear fusion with every collision, most collisions just send them flying off in different directions. But at the high temperatures and densities inside a star, the number of collisions is very high, so even though only a small percentage of the collisions end in fusion, its still a ridicuously high number of events per second (10 38 )!
The second activity, a Star Scale Model, is one I found on Astronomy Professor Kate Follette’s website. Students are given a table of 25 of the closest star systems to our sun, with the type of star, its distance and position (right ascension and declination). A second table has the ballon specs for each type of star, for example if the star is an M type then they need to blow up a red balloon so it has a radius of 2.5 inches. I didn’t have enough red balloons for all the M stars so we substituted circles of red paper of the appropriate size. This entire activity could be down with paper circles instead of balloons. We divided up the list of stars so each group of students made 6 to 7 stars and then came the hard part…. figuring out where to put them.
The farthest stars are 12 light years away. We used 1ft = 2 ly, so all the stars should be within 6 feet of our sun (a star shaped toy in the middle of the room). To figure out right ascension (R.A.) for each star, I placed signs at four points around the room 0/24 hours, 6 hr, 12 hr, 18hr. If a star is 4 ly from our sun with R.A. 14:29 hr then the students would place the star 2 feet from the ‘sun’ about half way between 12 and 18 hr. We didn’t worry about declination since we didn’t have an easy way to suspend the stars (ballons) in the air. The activity sheet has a number of questions that we answered as a group and everybody made a histogram of the star type distribution.
Lastly we did the Causation – Star Formation Part 1 activity from the Big History Project Unit 3.0. The activity has a causal map, showing the causes and effects for star formation. The map is complete with the exception of one circle, the trigger for star formation, which students filled in.
The middle school class also started with the moon observation page, the slideshow on star formation and nuclear fusion with mini-marshmallows. But instead of doing the entire Star model from scratch, I handed them balloons already labeled with one of the star names and they had to look it up on the table and figure out where it would go in our model. I also had them put together a Life Cycle of a Star from an interactive notebook, Astronomy & Space Science by Nitty Gritty Science that I bought on TeachersPayTeachers.com. The yellow sheet in the photo above has a one page description of the life cyce of a star that goes with the diagram they made.