## 20171017

### Online reading assignment: Kirchhoff's laws (NC campus)

Astronomy 210, fall semester 2017
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 Kirchhoff's laws.

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.
"How the spectrum of a star is like barcodes on products. If you understand the bar code system you can tell what product it corresponds to just by looking at it."

"The comparison between light lines of a spectrum of a star and bar codes. Working in retail as a teenager, I kind of understand how bar codes work and it makes a little more sense to me."

"That absorption spectrum was quite interesting in that some of the colors are missing. but it looks like a continuous spectrum."

"The Doppler effect for sound waves--it makes sense that sound waves moving toward you would be squished and the waves moving away from you would stretch."

"How sound waves change when when they are either coming near or moving away."

"The Doppler effect--I never knew that it applied to stars as well."

"I really liked the part about the Doppler effect and the different wavelengths. It's never been something I really thought about, but I've always enjoyed the sound, like 'neeoowww,' because my sisters and I think it's funny. Anyway, now I know why it sounds the way it does and I think thats cool."

Describe something you found confusing from the assigned textbook reading or presentation preview, and explain why this was personally confusing for you.
"What I found confusing from the presentation previews was trying to figure out what spectrum certain pictures belonged to. I figured that the lava picture belonged with the continuous spectra because it is hot but I'm still a bit confused and would like some clarification."

"The different type of spectra was a tad bit confusing I'm kind of lost on how they differ from one another."

"I had trouble distinguishing between the three spectra. At first it seemed easy, but now I can't tell between emission and absorption and when it's even continuous."

"The connection between dark absorption lines, bright emission lines, and dips and peaks in tge graphed spectrum. I had a hard time figuring out what the book wanted me to understand in those things."

"Blackbody radiation--how hot does a light bulb need to be to glow and give off radiation? How many wavelengths will be produced when it does give off radiation?"

"In the Doppler effect portion of the presentation previews, I was confused on how it works. The car moves towards you and the sound becomes "squished" but as it pulls away, the sound 'stretches,' that part I understand but how it compares to the light spectrum confuses me."

"Why are the wavelengths squished when the car is moving toward the observer and stretched when the car passes by or moving away."

I believe Pluto should be a planet.
 Strongly disagree. * [1] Disagree. ************ [12] Neutral. ***** [10] Agree. [0] Strongly Agree. *** [3]

Briefly explain your answer to the previous question (whether Pluto should be a planet).
"Pluto is a dwarf planet, and it just makes it more unique in the list of solar system objects!"

"I disagree, Pluto should not be considered a planet because it only meets two of the three criteria's for planets and if Pluto was to remain a planet then the rest of the dwarf planets that are similar to Pluto might as well be considered Planets as well."

"I mean it's a dwarf planet because it fits into two of the three planetary classification categories, so no it inst technically a planet but it is however a dwarf planet."

"I believe it should be a planet because it passes two of the three qualifications for planet classification. It is round and orbits the sun."

"After seeing the checklist, I'll stick with the answer revolving that. Sorry Pluto but you're not dominating of your orbit."

"Isn't like the only reason why it's not a planet is because it doesn't have a clear orbital path or something, and like they didn't want kids to have to memorize more planets? I think I remember reading an article on that somewhere. In my personal opinion it doesn't really matter, unless we plan to study it in depth."

"Before I agreed Pluto should be a planet because I felt bad it was getting left out. But Pluto doesn't dominate its own orbit so it technically can't be considered a planet."

"I know that according to the IAU Pluto is not considered a planet because it does not pass all three planet requirements but I still believe it should be a planet because everyone has the right to be whatever they want to be and I also don't want Pluto to kill us."

"Because it is a dwarf planet."

"A planet is a celestial body that (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and (c) has cleared the neighborhood around its orbit. Pluto is relatively round and orbits the sun, but it does not meet the criteria because its orbit crosses Neptune's orbit."

"I think that it makes sense, since Pluto is not able to dominate its orbit, it should not be a planet."

"If Pluto is a planet, it will not interfere with my life in any shape way or form, so I do not really have a preference :)"

"Pluto clearly fails the last requirement of a planet according to the revision of the definition of what a planet means set in place in 2006."

"I get why it is no longer considered a planet based on the classification, but I still think it should still be called a planet as long as it is clear how it is different from the other planets."

"Pluto doesn't fit the three criteria to be a planet. It is spherical and orbits the sun, but it has not cleared its orbit...yet. There might be hope for Pluto in the future."

"No, because it does not follow the guidelines for a planet."

"Pluto is classified as a dwarf planet because it doesn't dominate its orbit but rather shares the Keiper belt with other dwarf planets. I still think it's messed up that Pluto got kicked out of the main planets, but I understand why now."

"Based on our class lecture of how to determine what should and shouldn't be a planet, I don't believe Pluto qualifies. If astronomers were to qualify Pluto as a planet then they would need to qualify a whole lot more dwarf planets as planets and that would just get confusing."

"Pluto is scientifically categorized as a dwarf planet."

"Pluto is not a planet because it is a dwarf planet. The reason is that it doesn't dominate it's orbit around the sun."

"It doesn't make a diffrence in our solar system."

"It should not be a planet because it does not dominate its own orbit. Therefore, it gets to be in its own special category of dwarf planets, with others just like Pluto, so Pluto shouldn't be left out."

"Saying Pluto shouldn't be a planet after he already has been is like staring a board game and then making rules in the middle of it. That's not cool bro."

"If Pluto does not meet the prerequisite description of a planet (does not dominate its orbit), then I do not see why it would be considered one. I would not find it important enough to argue the point, unless for academia, however."

Match the spectrum type with their appearance.
(Only correct responses shown.)
Rainbow containing all colors: continuous [96%]
Rainbow with thin black lines: absorption [88%]
Colored lines on a black background: emission [92%]
Given off by hot, dense object: continuous [81%]
Given off by hot, diffuse gas atoms: emission [77%]
Passing through cool, diffuse gas atoms: [81%]

Hot, molten metal produces a __________ spectrum, which appears as a:
 continuous; rainbow. *************** [15] emission; series of bright lines on a dark background. ******* [7] absorption; series of dark lines on a rainbow background. *** [3] (Unsure/guessing/lost/help!) * [1]

The sun produces a __________ spectrum, which appears as a:
 continuous; rainbow. *** [3] emission; series of bright lines on a dark background. *** [3] absorption; series of dark lines on a rainbow background. ******************** [20] (Unsure/guessing/lost/help!) [0]

The lights atop the Fremont Theater in San Luis Obispo, CA, produces a __________ spectrum, which appears as a:
 continuous; rainbow. ***** [5] emission; series of bright lines on a dark background. ******************* [19] absorption; series of dark lines on a rainbow background. ** [2] (Unsure/guessing/lost/help!) [0]

Your instructor produces a __________ spectrum, which appears as a:
 continuous; rainbow. ** [2] emission; series of bright lines on a dark background. *********** [11] absorption; series of dark lines on a rainbow background. ******** [8] (Unsure/guessing/lost/help!) ***** [5]

The balrog from The Lord Of The Rings: The Fellowship Of The Ring produces a __________ spectrum, which appears as a:
 continuous; rainbow. ******* [7] emission; series of bright lines on a dark background. *********** [11] absorption; series of dark lines on a rainbow background. ***** [5] (Unsure/guessing/lost/help!) *** [3]

Suppose you are standing on the sidewalk as a car, with its horn continuously on, passes by (video link). The loudness of the car horn:
 starts loud, then gets quieter. ** [2] starts quiet, then gets louder. [0] starts quiet, gets louder, then goes back down to quiet. ************************ [24] starts loud, gets quieter, then goes back up to loud. [0] (Unsure/guessing/lost/help!) [0]

Suppose you are standing on the sidewalk as a car, with its horn continuously on, passes by (video link, same as above). The pitch (high note/low note) of the car horn:
 starts high, then drops lower. ************ [12] starts low, then goes higher. [0] starts low, goes higher, then drops back down to low. *********** [11] starts high, goes lower, then goes back up to high. *** [3] (Unsure/guessing/lost/help!) [0]

Ask the instructor an anonymous question, or make a comment. Selected questions/comments may be discussed in class.

"I did not like this chapter."

"I really hope you choose to be something other than the Doppler effect for Halloween." (#neeeow)

"What makes you not a big fan of The Big Bang Theory? (The Big Bang Theory makes fun of nerds and geeks. Shows like Community has fun with nerds and geeks.)

"YOU SHALL NOT PASS!!!!!!!!"

"Ok scientifically speaking, yeah, the balrog is pretty hot, but let's be real Liv Tyler is pretty damn HOTTTTTTT:) wouldn't you agree?"