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

Astronomy 210, fall semester 2016
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.
"Star life cycles--they say a million years is a short life, yet seems like a really long time for us."

"How the sun takes four hydrogen atoms and converts them into one helium atom and energy. This was interesting because when I was younger I just assumed that there was a bunch of gasoline in the sun supplying it with energy."

"How fusion releases energy."

"The birth of stars. Now I can school my fifth grade students with some astronomy they don't know [yet]."

"How dust similar in size to cigarette smoke creates a blue glow like cigarette smoke."

"I thought the different types of nebulae were totally wicked sweet. I thought it was cool how the dust clouds reflect blue light because the short wave lengths get scattered in all directions."

"I find all the different colors in the nebulae really interesting, because of what gives off theses different colors like the small and large particles of dust."

"I thought it was interesting to learn that there are only three nebulae colors."

"Emission nebula are just made out of hydrogen atoms and that is so simple but so amazing.."

"It all seems interesting but its very scienc-y and wordy to me. Once I understand it better I can find more of this interesting."

Describe something you found confusing from the assigned textbook reading or presentation preview, and explain why this was personally confusing for you.
"Fusion confuses me."

"Why does fusion exist?"

"Fusion rates for different mass stars."

"Fusion...I just don't get it."

"The proton-proton chain, I did not understand how the sun and stars produce energy."

"Fusion. I do not like chemistry! Help!"

"The whole temperature, pressure, and fusion rate thing really confused me."

"The fact that not all stars obey the cheerleader model confused me."

"Honestly I feel like memorizing the facts on nebulae will be difficult."

"The turn-off point with star clusters"

"Most of this information seemed difficult to grasp through my own thought processes, but this is all normally cleared up by the time lecture is over tomorrow night."

"Everything was pretty easy to understand."

Rank the luminosities of these main-sequence stars (1 = brightest, 3 = dimmest). (There are no ties.)
(Only correct responses shown.)
Massive: brightest luminosity [88%]
Medium-mass (sunlike): medium luminosity [91%]
Low mass (red dwarf): dimmest luminosity [94%]

Rank the fusion rates of these main-sequence stars (1 = fastest, 3 = slowest). (There are no ties.)
(Only correct responses shown.)
Massive: fastest fusion rate [75%]
Medium-mass (sunlike): medium fusion rate [97%]
Low mass (red dwarf): slowest fusion rate [78%]

Fusion requires high temperatures in order for nuclei to move quickly enough to:
break heavy elements apart.  *** [3]
create convection currents.  ** [2]
overcome gravity.  * [1]
overcome repulsion.  ********************* [21]
(Unsure/guessing/lost/help!)  ***** [5]

Briefly explain why "cold fusion" (producing energy from hydrogen fusion at room temperature) would be implausible.
"The hydrogen atoms would move too slow to overcome repulsion and collide with each other."

"The temperature is not high enough for hydrogen atoms to get squeezed and move quickly and will not result in a lot of them fusing together to release energy."

"During fusion, the temperature must be high, meaning high speeds, as this high temperature helps overcome the coulomb barrier that repels the two nuclei."

"In order for fusion to produce the energy from hydrogen it needs heat and the more the better it is at producing energy and fusing. Cold fusion is just not hot enough to do its thing."

"I did not get that part."

"Because we need such intense heat that the nuclei gets so hot that it almost melts together?"

Match the three different types of nebulae with their colors.
(Only correct responses shown.)
Emission: pink [75%]
Reflection: blue [81%]
Dark: brown/black [88%]

Match the three different types of nebulae with their composition.
(Only correct responses shown.)
Emission: hydrogen [84%]
Reflection: small dust particles [87%]
Dark: large dust particles [97%]

Rank the lifetimes of these main-sequence stars (1 = shortest, 3 = longest). (There are no ties.)
(Only correct responses shown.)
Massive: shortest main-sequence lifetime [67%]
Medium-mass (sunlike): medium main-sequence lifetime [93%]
Low mass (red dwarf): longest main-sequence lifetime [72%]

If there was an open invitation to a house party (no specific time given), when would you show up?
Early, or on time.  ***** [5]
When the most people should be there.  *************************** [27]
After most everyone has left.  [0]

Ask the instructor an anonymous question, or make a comment. Selected questions/comments may be discussed in class.
"How can I become a star in this class?" (Literally, or figuratively?)

"When does the International Space Station pass overhead next?" (Check out spotthestation.nasa.gov for your area.)

"Hopefully I pass this class." (I hope so, too.)

"What does fusion have to do with cheerleading? I still don't get that."

"You are my favorite teacher--I wish I had you more than one time a week."

No comments: