Astronomy 210 Quiz 6, fall semester 2012
Cuesta College, San Luis Obispo, CA
__________ is/are evidence that spiral arms extend across the entire Milky Way disk.
(A) Positions of massive main sequence stars.
(B) Radio waves emitted from cold hydrogen gas clouds.
(C) Globular cluster positions.
(D) The Doppler effect.
Correct answer: (B)
Radio waves are relatively unaffected by interstellar gas and dust, and enable the locations of cold hydrogen gas clouds in most of the Milky Way to be mapped. Positions of massive main sequence stars can only give an indication of spiral arms immediately adjacent to the spur the sun is located in; and globular cluster positions are used to determine the location of the Milky Way.
Section 70158
Exam code: quiz06Sl4m
(A) : 9 students
(B) : 4 students
(C) : 13 students
(D) : 4 students
Success level: 19% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.38
Showing posts with label spiral arm. Show all posts
Showing posts with label spiral arm. Show all posts
20120422
Astronomy quiz question: interstellar hydrogen hyperfine lines
Astronomy 210 Quiz 6, spring semester 2012
Cuesta College, San Luis Obispo, CA
Radio waves emitted from cold hydrogen gas clouds provides evidence of:
(A) spiral arms extending across the entire Milky Way disk.
(B) the central supermassive black hole.
(C) dark matter.
(D) unequal amounts of matter and antimatter.
Correct answer: (A)
Radio waves are relatively unaffected by interstellar gas and dust, and enable the locations of cold hydrogen gas clouds in most of the Milky Way to be mapped.
Section 30674
Exam code: quiz06niLl
(A) : 16 students
(B) : 5 students
(C) : 5 students
(D) : 4 students
"Success level": 53% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.44
Cuesta College, San Luis Obispo, CA
Radio waves emitted from cold hydrogen gas clouds provides evidence of:
(A) spiral arms extending across the entire Milky Way disk.
(B) the central supermassive black hole.
(C) dark matter.
(D) unequal amounts of matter and antimatter.
Correct answer: (A)
Radio waves are relatively unaffected by interstellar gas and dust, and enable the locations of cold hydrogen gas clouds in most of the Milky Way to be mapped.
Section 30674
Exam code: quiz06niLl
(A) : 16 students
(B) : 5 students
(C) : 5 students
(D) : 4 students
"Success level": 53% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.44
20111117
Astronomy quiz question: spiral arm tracers
Astronomy 210 Quiz 6, fall semester 2011
Cuesta College, San Luis Obispo, CA
Spiral arms can be traced through the sun's neighborhood by locating the positions of spiral tracers such as:
(A) Cepheid variable stars.
(B) globular clusters.
(C) type Ia and type II supernovae.
(D) massive stars.
Correct answer: (D).
Massive stars are luminous and short-lived, so they only be located near where they were born from a spiral arm density wave. Cepheid variable stars are used to determine the distances to globular clusters in the halo of the Milky Way, and the distribution of globular clusters is used to locate the center of the Milky Way. Observations of type Ia and type II are used to determine the distances to other galaxies.
Section 70158
Exam code: quiz06pOp1
(A) : 9 students
(B) : 11 students
(C) : 4 students
(D) : 7 students
(No response: 1 student)
Success level: 27% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): -0.13
Cuesta College, San Luis Obispo, CA
Spiral arms can be traced through the sun's neighborhood by locating the positions of spiral tracers such as:
(A) Cepheid variable stars.
(B) globular clusters.
(C) type Ia and type II supernovae.
(D) massive stars.
Correct answer: (D).
Massive stars are luminous and short-lived, so they only be located near where they were born from a spiral arm density wave. Cepheid variable stars are used to determine the distances to globular clusters in the halo of the Milky Way, and the distribution of globular clusters is used to locate the center of the Milky Way. Observations of type Ia and type II are used to determine the distances to other galaxies.
Section 70158
Exam code: quiz06pOp1
(A) : 9 students
(B) : 11 students
(C) : 4 students
(D) : 7 students
(No response: 1 student)
Success level: 27% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): -0.13
20110422
Astronomy quiz question: Milky Way spiral arm evidence
Astronomy 210 Quiz 6, Spring Semester 2011
Cuesta College, San Luis Obispo, CA
__________ is/are evidence that spiral arms extend across the Milky Way disk.
(A) Globular cluster positions.
(B) Positions of massive main sequence stars.
(C) The Doppler effect.
(D) Radio waves from cold hydrogen gas clouds.
Correct answer: (D)
While the luminous stars in response (B) is used to map out an indication of spiral arms and spurs in our immediate vicinity of the Milky Way, response (D) refers to the radio waves from cold hydrogen gas clouds that are relatively unobstructed by the interstellar gas and dust, and this data allows essentially the entire spiral arm structure of the Milky Way to be mapped. Response (A) refers to how the location of the center of the Milky Way is determined.
Section 30674
Exam code: quiz06n4Ke
(A) : 19 students
(B) : 8 students
(C) : 3 students
(D) : 7 students
"Success level": 22% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.30
Cuesta College, San Luis Obispo, CA
__________ is/are evidence that spiral arms extend across the Milky Way disk.
(A) Globular cluster positions.
(B) Positions of massive main sequence stars.
(C) The Doppler effect.
(D) Radio waves from cold hydrogen gas clouds.
Correct answer: (D)
While the luminous stars in response (B) is used to map out an indication of spiral arms and spurs in our immediate vicinity of the Milky Way, response (D) refers to the radio waves from cold hydrogen gas clouds that are relatively unobstructed by the interstellar gas and dust, and this data allows essentially the entire spiral arm structure of the Milky Way to be mapped. Response (A) refers to how the location of the center of the Milky Way is determined.
Section 30674
Exam code: quiz06n4Ke
(A) : 19 students
(B) : 8 students
(C) : 3 students
(D) : 7 students
"Success level": 22% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.30
20100428
Astronomy quiz question: density wave theory
Astronomy 210 Quiz 6, Spring Semester 2010
Cuesta College, San Luis Obispo, CA
According to the density wave theory, a gas cloud forms new stars as it passes through a spiral arm because:
(A) it slows down and compresses.
(B) it gathers more interstellar material.
(C) it will collide with dark matter.
(D) its metals will break down into non-metals.
Correct answer: (A)
According to the density wave theory, a gas cloud passing through a spiral arm does not collect new material to make new stars, but compresses as it encounters a "traffic jam" located there, which triggers new star formation.
Section 30674
(A) : 31 students
(B) : 3 students
(C) : 1 student
(D) : 2 students
Success level: 76% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.45
This question was asked in Fall semester 2009 as a quiz question.
Cuesta College, San Luis Obispo, CA
According to the density wave theory, a gas cloud forms new stars as it passes through a spiral arm because: (A) it slows down and compresses.
(B) it gathers more interstellar material.
(C) it will collide with dark matter.
(D) its metals will break down into non-metals.
Correct answer: (A)
According to the density wave theory, a gas cloud passing through a spiral arm does not collect new material to make new stars, but compresses as it encounters a "traffic jam" located there, which triggers new star formation.
Section 30674
(A) : 31 students
(B) : 3 students
(C) : 1 student
(D) : 2 students
Success level: 76% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.45
This question was asked in Fall semester 2009 as a quiz question.
20091120
Astronomy quiz question: density wave theory
Astronomy 210 Quiz 6, Fall Semester 2009
Cuesta College, San Luis Obispo, CA
According to the density wave theory, a gas cloud forms new stars as it passes through a spiral arm because:
(A) it slows down and compresses.
(B) it gathers more interstellar material.
(C) it will collide with dark matter.
(D) its metals will break down into non-metals.
Correct answer: (A)
According to the density wave theory, a gas cloud passing through a spiral arm does not collect new material to make new stars, but compresses as it encounters a "traffic jam" located there, which triggers new star formation.
Section 70158
(A) : 37 students
(B) : 4 students
(C) : 1 student
(D) : 0 students
Success level: 89% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.50
Cuesta College, San Luis Obispo, CA
According to the density wave theory, a gas cloud forms new stars as it passes through a spiral arm because: (A) it slows down and compresses.
(B) it gathers more interstellar material.
(C) it will collide with dark matter.
(D) its metals will break down into non-metals.
Correct answer: (A)
According to the density wave theory, a gas cloud passing through a spiral arm does not collect new material to make new stars, but compresses as it encounters a "traffic jam" located there, which triggers new star formation.
Section 70158
(A) : 37 students
(B) : 4 students
(C) : 1 student
(D) : 0 students
Success level: 89% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.50
20090619
TireWriter(TM): spiral arm formation model
http://www.flickr.com/photos/waiferx/3567609008/
Originally uploaded by Waifer X
TireWriter(TM), from Schwinn, demonstrating how density waves create the spiral arm structure of the Milky Way. Massive main-sequence stars are luminous and short-lived, and thus are only seen where their formation is triggered. Video by Cuesta College Physical Sciences Division instructor Dr. Patrick M. Len.
20090608
Astronomy final exam question: red dwarfs versus spiral arms
Astronomy 210 Final Exam, Spring Semester 2009
Cuesta College, San Luis Obispo, CA
[20 points.] Red dwarfs in the disk of the Milky Way are never found near the spiral arm where they were born. Explain why this is so, using the properties of stars and galaxies.
Solution and grading rubric:
Section 30676
p: 20 students
r: 6 students
t: 4 students
v: 16 students
x: 1 student
y: 1 student
z: 0 students
A sample "p" response (from student 0008):
Another sample "p" response (from student 2517), accompanied by a diagram:
Another sample "p" response (from student 9802):
A sample "r" response (from student 4080), with stars moving radially outwards from rather than tangentially around the center of the Milky Way:
A sample "v" response (from student 8675):
A sample "x" response (from student 1192), at least speculating that some sort of migration is involved:
Cuesta College, San Luis Obispo, CA
[20 points.] Red dwarfs in the disk of the Milky Way are never found near the spiral arm where they were born. Explain why this is so, using the properties of stars and galaxies.
Solution and grading rubric:
- p = 20/20:
Correct. Due to their extremely long lifetimes, red dwarfs will make many orbits around the Milky Way, long after being born in and drifting away from their molecular clouds of origin, in which star formation is triggered by passing through the density waves located at the spiral arms. - r = 16/20:
Nearly correct (explanation weak, unclear or only nearly complete); includes extraneous/tangential information; or has minor errors. At least understands lifetimes and Milky Way motions. - t = 12/20:
Contains right ideas, but discussion is unclear/incomplete or contains major errors. Understands only lifetimes, or Milky Way motions. - v = 8/20:
Limited relevant discussion of supporting evidence of at least some merit, but in an inconsistent or unclear manner. Explanation primarily based on moving away from molecular cloud due to drift, being pulled away by gravity from other stars and/or galaxies, dark matter/energy, "redshifts," or expansion of space. - x = 4/20:
Implementation/application of ideas, but credit given for effort rather than merit. - y = 2/20:
Irrelevant discussion/effectively blank. - z = 0/20:
Blank.
Section 30676
p: 20 students
r: 6 students
t: 4 students
v: 16 students
x: 1 student
y: 1 student
z: 0 students
A sample "p" response (from student 0008):
Another sample "p" response (from student 2517), accompanied by a diagram:
Another sample "p" response (from student 9802):
A sample "r" response (from student 4080), with stars moving radially outwards from rather than tangentially around the center of the Milky Way:
A sample "v" response (from student 8675):
A sample "x" response (from student 1192), at least speculating that some sort of migration is involved:
20081105
Astronomy clicker question: spiral arm with supergiants and red dwarfs
Astronomy 210, Fall Semester 2008
Cuesta College, San Luis Obispo, CA
Students were asked the following clicker question (Classroom Performance System, einstruction.com) at the end of their learning cycle:
It is possible for red dwarfs and supergiants to be found within the same spiral arm if:
(A) they began their main sequence lives in different spiral arms.
(B) the supergiants have already exploded as type II supernovae, but this light has not yet reached the Earth.
(C) they contain different concentrations of metals (elements heavier than hydrogen and helium).
(D) they are both remnants of medium mass main sequence stars.
(E) (I'm lost, and don't know how to answer this.)
Section 70158
(A) : 25 students
(B) : 7 students
(C) : 6 students
(D) : 13 students
(E) : 1 student
This question was asked again after displaying the tallied results with the lack of consensus, with the following results. No comments were made by the instructor, in order to see if students were going to be able to discuss and determine the correct answer among themselves.
Section 70158
(A) : 38 students
(B) : 5 students
(C) : 3 students
(D) : 8 students
(E) : 0 students
Correct answer: (A)
Massive stars live for a brief amount of time, evolving rapidly from protostars to main sequence stars to supergiants to type II supernovae. At the other extreme, low mass stars live for an inordinately long time, evolving from protostars to the main sequence, where they all still exist to this day as red dwarfs. So in order for a supergiant to be located in the same spiral arm as a red dwarf, they must have been born in separate locations--the massive star is born, lives, and dies within the same spiral arm, while the red dwarf is on its nth round trip, passing through the spiral arm. Responses (B) and (C) are not an important factors, while response (D) is obviously false.
Pre- to post- peer-interaction gains:
pre-interaction correct = 48%
post-interaction correct = 70%
Hake (normalized) gain <g> = 43%
Section 70160 (pre-)
(A) : 14 students
(B) : 7 students
(C) : 3 students
(D) : 4 students
(E) : 0 students
Section 70160 (post-)
(A) : 20 students
(B) : 8 students
(C) : 0 students
(D) : 0 students
(E) : 0 students
Pre- to post- peer-interaction gains:
pre-interaction correct = 50%
post-interaction correct = 71%
Hake (normalized) gain <g> = 43%
Cuesta College, San Luis Obispo, CA
Students were asked the following clicker question (Classroom Performance System, einstruction.com) at the end of their learning cycle:
It is possible for red dwarfs and supergiants to be found within the same spiral arm if:
(A) they began their main sequence lives in different spiral arms.
(B) the supergiants have already exploded as type II supernovae, but this light has not yet reached the Earth.
(C) they contain different concentrations of metals (elements heavier than hydrogen and helium).
(D) they are both remnants of medium mass main sequence stars.
(E) (I'm lost, and don't know how to answer this.)
Section 70158
(A) : 25 students
(B) : 7 students
(C) : 6 students
(D) : 13 students
(E) : 1 student
This question was asked again after displaying the tallied results with the lack of consensus, with the following results. No comments were made by the instructor, in order to see if students were going to be able to discuss and determine the correct answer among themselves.
Section 70158
(A) : 38 students
(B) : 5 students
(C) : 3 students
(D) : 8 students
(E) : 0 students
Correct answer: (A)
Massive stars live for a brief amount of time, evolving rapidly from protostars to main sequence stars to supergiants to type II supernovae. At the other extreme, low mass stars live for an inordinately long time, evolving from protostars to the main sequence, where they all still exist to this day as red dwarfs. So in order for a supergiant to be located in the same spiral arm as a red dwarf, they must have been born in separate locations--the massive star is born, lives, and dies within the same spiral arm, while the red dwarf is on its nth round trip, passing through the spiral arm. Responses (B) and (C) are not an important factors, while response (D) is obviously false.
Pre- to post- peer-interaction gains:
pre-interaction correct = 48%
post-interaction correct = 70%
Hake (normalized) gain <g> = 43%
Section 70160 (pre-)
(A) : 14 students
(B) : 7 students
(C) : 3 students
(D) : 4 students
(E) : 0 students
Section 70160 (post-)
(A) : 20 students
(B) : 8 students
(C) : 0 students
(D) : 0 students
(E) : 0 students
Pre- to post- peer-interaction gains:
pre-interaction correct = 50%
post-interaction correct = 71%
Hake (normalized) gain <g> = 43%
Subscribe to:
Posts (Atom)