Online reading assignment: fusion, nebulae, star cluster ages (NC campus)

Astronomy 210, spring semester 2014
Cuesta College, San Luis Obispo, CA

Students have a weekly online reading assignment (hosted by SurveyMonkey.com), where they answer questions based on reading their textbook, material covered in previous lectures, opinion questions, and/or asking (anonymous) questions or making (anonymous) comments. Full credit is given for completing the online reading assignment before next week's lecture, regardless if whether their answers are correct/incorrect. Selected results/questions/comments are addressed by the instructor at the start of the following lecture.

The following questions were asked on reading textbook chapters and previewing presentations on fusion, nebulae, and star cluster ages.

Selected/edited responses are given below.

Describe something you found interesting from the assigned textbook reading or presentation preview, and explain why this was personally interesting for you.
"I found the different types of nebulae to be very interesting because I liked how they all produced distinct colors that make it easy for us to identify them."

"Nebulae. They are interesting to me because of their beauty."

"That when you look at stars you are really just looking at them from the past. That is crazy and kinda hard to wrap my brain around."

"Forgot how beautiful the universe can be."

"I thought that it's interesting that there are only blue, pink, and black in the different clouds in outer space. I just think it's interesting because I always see pictures with crazy colors but now I know they're fake."


"Fusion, the amount of pressure and temperature required to get hydrogen atoms moving and colliding together. This releases energy and the greater the pressure and temperature the more energy is released. I found this interesting because I figured that there had to be some sort of energy source in stars but I've always wondered what exactly caused the release of energy."

"Why the off the sequence stars don't follow the rule of mass correlating with luminosity. All the other stars follow this rule, why wouldn't these?"

"The requirements for fusion, I find it confusing because I'm not 100% sure on the subject."

"Star formation."

Describe something you found confusing from the assigned textbook reading or presentation preview, and explain why this was personally confusing for you.
"I followed all of the presentations right up until the turn-off point. I was confused because I wasn't sure exactly what it is. Is it the point at which it can be defined as low mass, med mass, or high mass?"

"I found the star cluster age discussion confusing. I just don't understand it."

Fusion requires high temperatures in order for nuclei to move quickly enough to:
break heavy elements apart.  **** [4]
create convection currents.  *** [3]
overcome gravity.  * [1]
overcome repulsion.  ********** [10]
(Unsure/guessing/lost/help!)  [0]

Briefly explain why "cold fusion" (producing energy from hydrogen fusion at room temperature) would be implausible.
"The protons wouldn't be able to move fast enough to collide, they would repel instead."

"Because high temperatures need be present for collisions between nuclei to take place."

"I have no idea."

Rank the fusion rates of these main-sequence stars (1 = fastest, 3 = slowest). (There are no ties.)
(Only correct responses shown.)
Low mass (red dwarf): slowest fusion rate [89%]
Medium-mass (sunlike): medium fusion rate [100%]
Massive: fastest fusion rate [89%]

Match the three different types of nebulae with their colors.
(Only correct responses shown.)
Emission: pink [83%]
Reflection: blue [85%]
Dark: brown/black [98%]

Match the three different types of nebulae with their composition.
(Only correct responses shown.)
Emission: hydrogen [83%]
Reflection: small dust particles [83%]
Dark: large dust particles [83%]

If there was an open invitation to a house party (no specific time given), when would you show up?
Early, or on time.  ** [2]
When the most people should be there.  **************** [16]
After most everyone has left.  [0]

Ask the instructor an anonymous question, or make a comment. Selected questions/comments may be discussed in class.
"These presentations were very thorough and helpful!"

"The emission clouds in space are pretty."

"Do I exist?"

"Quiz on April Fool's Day = not cool."

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