20141214

Education research: SPCI statistics (fall semester 2014)

Students at Cuesta College (San Luis Obispo, CA) were administered the Star Properties Concept Inventory (SPCI version 3.0, developed by Janelle Bailey, University of Nevada-Las Vegas) during the first and the last week of instruction. Astronomy 210 is a one-semester introductory general science course, with a separate optional adjunct laboratory (Astronomy 210L).

The pre- to post-test gain for this semester at Cuesta College (excluding students with negative informed consent forms (*.pdf), and missing pre- or post-tests) is:

Astronomy 210 fall semester 2014 sections 70158, 70160
N = 74 (matched-pairs)
<initial%>= 34% ± 15%
<final%>= 60% ± 16%
<g>= 0.39 ± 0.22 (matched-pairs); 0.39 (class-wise)

This semester's SPCI pre- and post-instruction scores are slightly higher than results from previous semesters at Cuesta College, and this semester's gain is much higher than those in previous semesters.

20141213

Astronomy midterm question: habitability of Mars forming closer to the sun

absolute magnitude, apparent magnitude, astronomy essay question, stellar distances Astronomy 210 Midterm 2, fall semester 2014
Cuesta College, San Luis Obispo, CA

An astronomy question on an online discussion board[*] was asked:
Pd: If Mars had originally formed closer to the sun, would it be more habitable today?
qu: Mars closer to the sun would be warmer, but actually less habitable with less water and atmosphere.
Discuss how Mars forming closer to the sun would have less water and atmosphere today, and how you know this. Explain using the properties of planet mass, atmosphere, and geological activity.

[*] http://answers.yahoo.com/question/index?qid=20141101111207AAt4Wdm.

Solution and grading rubric:
  • p:
    Correct. Discusses why both statements are correct about Mars located closer to the sun and being warmer would result in:
    1. less water, due to warmer temperatures evaporating all available water (or ultraviolet light breaking apart water molecules);
    2. less atmosphere, as warmer temperatures would allow atmosphere molecules to move faster and more easily escape from Mars' weak gravity.
  • r:
    Nearly correct (explanation weak, unclear or only nearly complete); includes extraneous/tangential information; or has minor errors. One of the two points (1)-(2) correct, other is problematic/incomplete.
  • t:
    Contains right ideas, but discussion is unclear/incomplete or contains major errors. Both points (1)-(2) problematic/incomplete, or one is correct while the other is garbled/missing.
  • v:
    Limited relevant discussion of supporting evidence of at least some merit, but in an inconsistent or unclear manner. At least attempts to use relationships between planet location and mass with atmosphere temperature and retention.
  • x:
    Implementation/application of ideas, but credit given for effort rather than merit. Discussion not clearly based on relationships between planet location and mass with atmosphere temperature and retention.
  • y:
    Irrelevant discussion/effectively blank.
  • z:
    Blank.
Grading distribution:
Section 70158
Exam code: midterm02s0vA
p: 10 students
r: 4 students
t: 18 students
v: 10 students
x: 3 students
y: 0 students
z: 0 students

Section 70160
Exam code: midterm02n4Rs
p: 7 students
r: 6 students
t: 15 students
v: 2 students
x: 3 students
y: 0 students
z: 0 students

A sample "p" response (from student 1123):

A sample "x" response (from student):

Astronomy midterm question: distance modulus comparison

Astronomy 210 Midterm 2, fall semester 2014
Cuesta College, San Luis Obispo, CA

An astronomy question on an online discussion board[*] was asked:
??: Two stars have these apparent magnitudes and absolute magnitudes. What can we say about their relative distances from Earth?
m
apparent
magnitude
MV
absolute visual
magnitude
Star X +9 +2
Star Y +4 +6

ba: The relative distances of stars can be determined by subtracting the absolute magnitude from the apparent magnitude. The more positive the answer, the farther away the star. For your example, Star X has a magnitude difference of 9 – 2 = +7, while the difference for Star Y is 4 – 6 = –2.
Discuss why this reasoning is incorrect, and how you know this. Explain using the relationships between apparent magnitude, absolute magnitude, and distance.

[*] http://answers.yahoo.com/question/index?qid=20090321011229AAwvrJw.

Solution and grading rubric:
  • p:
    Correct. Understands difference between apparent magnitude m (brightness as seen from Earth, when placed at their actual distance from Earth) and absolute visual magnitude (MV (brightness as seen from Earth, when placed 10 parsecs away), and discusses:
    1. that for star X, the brightness it has at its location (m = +9) is dimmer than its brightness when placed 10 parsecs away (MV = +2), so its distance is greater than 10 parsecs; while for star Y, the brightness it has at its location (m = +4) is brighter than its brightness when placed 10 parsecs away (MV = +6), so its distance is closer than 10 parsecs;
    2. how this is consistent with the method proposed by "ba" (which follows directly from the "distance modulus" (mMV) in the relation (mMV) = 5·log(d) – 5), as star X has a distance modulus of +7 ("more positive the answer, the farther away the star") and star Y has a distance modulus of –2 (which would indicate that it is closer than star X).
  • r:
    Nearly correct (explanation weak, unclear or only nearly complete); includes extraneous/tangential information; or has minor errors. One of the two points (1)-(2) correct, other is problematic/incomplete.
  • t:
    Contains right ideas, but discussion is unclear/incomplete or contains major errors. Only one of the two points (1)-(2) correct, other is missing, or both are problematic.
  • v:
    Limited relevant discussion of supporting evidence of at least some merit, but in an inconsistent or unclear manner. At least attempts to use relationships between apparent magnitudes, absolute visual magnitudes, and distances.
  • x:
    Implementation/application of ideas, but credit given for effort rather than merit. Discussion based on garbled definitions of, or not based on proper relationships between apparent magnitudes, absolute visual magnitudes, and distances.
  • y:
    Irrelevant discussion/effectively blank.
  • z:
    Blank.
Grading distribution:
Section 70158
Exam code: midterm02s0vA
p: 14 students
r: 9 students
t: 12 students
v: 6 students
x: 4 students
y: 0 students
z: 0 students

A sample "p" response (from student 0978):

A sample "t" response (from student 4743):

Astronomy midterm question: doubling star distance

Astronomy 210 Midterm 2, fall semester 2014
Cuesta College, San Luis Obispo, CA

An astronomy question on an online discussion board[*] was asked:
JK: A star has an apparent magnitude of +12.5 and an absolute magnitude of –2.0. If the star is moved twice as far away (distance is doubled), would its apparent magnitude then be –0.5? I don't know if I am correct.
Discuss why this reasoning is incorrect, and how you know this. Explain using the relationships between apparent magnitude, absolute magnitude, and distance.

[*] http://answers.yahoo.com/question/index?qid=20090216102612AAzRHWy.

Solution and grading rubric:
  • p:
    Correct. Understands difference between apparent magnitude m (brightness as seen from Earth, when placed at their actual distance from Earth) and absolute visual magnitude (MV (brightness as seen from Earth, when placed 10 parsecs away), and discusses how placing a star farther away will affect its apparent magnitude, making it dimmer (a larger positive number than +12.5) instead of brighter (the incorrect value of –0.5).
  • r:
    Nearly correct (explanation weak, unclear or only nearly complete); includes extraneous/tangential information; or has minor errors.
  • t:
    Contains right ideas, but discussion is unclear/incomplete or contains major errors.
  • v:
    Limited relevant discussion of supporting evidence of at least some merit, but in an inconsistent or unclear manner. At least attempts to use relationships between apparent magnitudes, absolute visual magnitudes, and distances.
  • x:
    Implementation/application of ideas, but credit given for effort rather than merit. Discussion based on garbled definitions of, or not based on proper relationships between apparent magnitudes, absolute visual magnitudes, and distances.
  • y:
    Irrelevant discussion/effectively blank.
  • z:
    Blank.
Grading distribution:
Section 70160
Exam code: midterm02n4Rs
p: 7 students
r: 6 students
t: 15 students
v: 2 students
x: 3 students
y: 0 students
z: 0 students

A sample "p" response (from student 0500):

Astronomy midterm question: bigger, more luminous stars always cooler or hotter?

Astronomy 210 Midterm 2, fall semester 2014
Cuesta College, San Luis Obispo, CA

An astronomy question on an online discussion board[*] was asked:
Pd: Are the bigger, more luminous stars always the cooler stars?
Sa: You wouldn't be right because "more luminous" means more energy output, which means bigger and hotter.
Discuss why this answer is incorrect, and how you know this. Explain using Wien's law, the Stefan-Boltzmann law and/or an H-R diagram.

[*] http://answers.yahoo.com/question/index?qid=20141031235350AAd46qs.

Solution and grading rubric:
  • p:
    Correct. Uses Wien's law, the Stefan-Boltzmann law and/or interprets H-R diagram to discuss how a more luminous star does not necessarily have to be both bigger and hotter, by comparing:
    bright/larger/cooler vs. dim/smaller/hotter stars;
    bright/larger/(same temperature) vs. dim/smaller/(same temperature) stars;
    bright/smaller/hotter vs. dim/larger/cooler stars;
    bright/(same size)/hotter vs. dim/(same size)/cooler stars.
  • r:
    Nearly correct (explanation weak, unclear or only nearly complete); includes extraneous/tangential information; or has minor errors. Or as (p), but may instead compare:
    (same brightness)/smaller/hotter vs. (same brightness)/larger/cooler stars;
    brighter/larger/hotter vs. dim/smaller/cooler star;
    thus not sufficiently discussing why the response would not always be correct.
  • t:
    Contains right ideas, but discussion is unclear/incomplete or contains major errors. At last discussion demonstrates understanding of Wien's law, H-R diagram and/or the Stefan-Boltzmann law.
  • v:
    Limited relevant discussion of supporting evidence of at least some merit, but in an inconsistent or unclear manner. At least attempts to use Wien's law, H-R diagram and/or the Stefan-Boltzmann law.
  • x:
    Implementation/application of ideas, but credit given for effort rather than merit. Discussion not clearly based on Wien's law, H-R diagram and/or the Stefan-Boltzmann law.
  • y:
    Irrelevant discussion/effectively blank.
  • z:
    Blank.
Grading distribution:
Section 70158
Exam code: midterm02s0vA
p: 20 students
r: 14 students
t: 6 students
v: 3 students
x: 1 student
y: 0 students
z: 0 students

Section 70160
Exam code: midterm02n4Rs
p: 20 students
r: 7 students
t: 2 students
v: 2 students
x: 2 students
y: 0 students
z: 0 students

A sample "p" response (from student 1327) comparing a bright/larger/cooler star versus a dim/smaller/hotter star:

A sample "p" response (from student 5656) comparing a bright/larger star that has the same temperature as a dim/smaller star:

A sample "p" response (from student 5309) comparing a bright/smaller/hotter star versus a dim/larger/cooler star:

A sample "p" response (from student 1795) comparing a bright/hotter star that has the same temperature as a dim/cooler star:

Astronomy current events question: Fornax Dwarf Spheroidal Galaxy globular cluster formation theories

Astronomy 210L, fall semester 2014
Cuesta College, San Luis Obispo, CA

Students are assigned to read online articles on current astronomy events, and take a short current events quiz during the first 10 minutes of lab. (This motivates students to show up promptly to lab, as the time cut-off for the quiz is strictly enforced!)
Søren Larsen , Frank Grundahl, Georgia Bladon, "The Riddle of the Missing Stars," (November 20, 2014)
http://www.spacetelescope.org/news/heic1425/
Hubble Space Telescope observations of globular clusters in the Fornax Dwarf Spheroidal galaxy present questions regarding theories of the Milky Way's:
(A) supermassive black hole mass.
(B) ratio of luminous to dark matter.
(C) number of spiral arms.
(D) red dwarf population.
(E) globular cluster formation.

Correct answer: (E)

Student responses
Sections 70178, 70186
(A) : 6 students
(B) : 4 students
(C) : 4 students
(D) : 2 students
(E) : 20 students

Astronomy current events question: Jupiter's Red Spot color origins

Astronomy 210L, fall semester 2014
Cuesta College, San Luis Obispo, CA

Students are assigned to read online articles on current astronomy events, and take a short current events quiz during the first 10 minutes of lab. (This motivates students to show up promptly to lab, as the time cut-off for the quiz is strictly enforced!)
Preston Dyches, "Jupiter's Red Spot Most Likely A Sunburn, Not a Blush," (November 11, 2014)
http://www.jpl.nasa.gov/news/news.php?feature=4372
Jet Propulsion Laboratory scientists propose that the color of Jupiter's Great Red Spot is due to chemicals reacting with sunlight, based on comparing observations with:
(A) increased activity due to solar flares.
(B) correlated auroral activity.
(C) decreasing wind speeds.
(D) samples brought back by the Cassini mission.
(E) experiments in Earth-based laboratories.

Correct answer: (E)

Student responses
Sections 70178, 70186
(A) : 8 students
(B) : 7 students
(C) : 4 students
(D) : 5 students
(E) : 13 students

Astronomy current events question: observing effects of C/2013 A1 (Siding Spring) on Mars' atmosphere

Astronomy 210L, fall semester 2014
Cuesta College, San Luis Obispo, CA

Students are assigned to read online articles on current astronomy events, and take a short current events quiz during the first 10 minutes of lab. (This motivates students to show up promptly to lab, as the time cut-off for the quiz is strictly enforced!)
APPEL news staff, "A Rare Event Offers Insight into Solar System Origins," (November 24, 2014)
http://appel.nasa.gov/2014/11/24/a-rare-event-offers-insight-into-solar-system-origins/
NASA and European Space Agency spacecraft are measuring the effects on Mars' atmosphere due to dust deposited by a:
(A) reactivated volcano.
(B) nearby comet.
(C) small asteroid impact.
(D) planet-wide sandstorm.
(E) solar flare.

Correct answer: (B)

Student responses
Sections 70178, 70186
(A) : 5 students
(B) : 29 students
(C) : 1 student
(D) : 2 students
(E) : 0 students

Astronomy quiz question: type Ia supernova in distant galaxy

Astronomy 210 Quiz 7, fall semester 2014
Cuesta College, San Luis Obispo, CA

An observer in San Luis Obispo, CA detects a type Ia supernova in a distant galaxy right now. An observer inside that distant galaxy, very close to that location would observe right now a:
(A) nova.
(B) supergiant.
(C) white dwarf.
(D) type Ia supernova.
(E) medium-mass main-sequence star.
(F) (None of the above choices, as there is nothing left at that location right now.)

Correct answer (highlight to unhide): (F)

A type Ia supernova occurs when a white dwarf star takes hydrogen from a close binary companion star such that its carbon-oxygen core will have sufficient pressure to undergo fusion, and explode and completely destroy itself.

The finite speed of light results in information of events that occurred in the past taking time to reach distant locations, such that when we observe this type Ia supernova, the white dwarf has already exploded and is no more. An observer much closer to that location would have already seen that type Ia supernova explosion before us, and will now observe nothing remaining at that location.

Section 70158
Exam code: quiz07su4R
(A) : 1 student
(B) : 2 students
(C) : 13 students
(D) : 8 students
(E) : 3 students
(F) : 12 students

Success level: 33% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.17

Section 70160
Exam code: quiz07n0Lb
(A) : 2 students
(B) : 1 student
(C) : 13 students
(D) : 1 student
(E) : 2 students
(F) : 13 students

Success level: 45% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.24

Astronomy quiz question: products of fusion in the sun's core

Astronomy 210 Quiz 7, fall semester 2014
Cuesta College, San Luis Obispo, CA

Fusion reactions in the sun's core produced the:
(A) hydrogen in the sun.
(B) gold and silver in Earth's crust.
(C) heat inside Earth's core.
(D) lithium in car batteries.
(E) (More than one of the above choices.)
(F) (None of the above choices.)

Correct answer (highlight to unhide): (F)

The sun is a medium-mass main sequence star, so it is currently fusing hydrogen into helium in its core.

Hydrogen is merely the raw ingredient of the universe, and was created in the first few moments of the big bang, while lithium was produced by fusion few minutes after the start of the big bang.

Massive stars fuse hydrogen into heavier elements in their cores up through iron, and as a result of undergoing a type II supernova they produce heavier elements than iron, such as gold and silver. These heavy elements from the remnants of a previous generation massive star would then be incorporated into the formation of Earth in the early solar system.

The heat in Earth's core was produced from the conversion of gravitational potential energy during its formation, and also from the radioactive decay of unstable heavy elements (produced by a type II supernova of a previous generation massive star) in its core.

Section 70158
Exam code: quiz07su4R
(A) : 14 students
(B) : 12 students
(C) : 4 students
(D) : 1 student
(E) : 8 students
(F) : 5 students

Success level: 16% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.17

Section 70160
Exam code: quiz07n0Lb
(A) : 8 students
(B) : 7 students
(C) : 1 student
(D) : 1 student
(E) : 4 students
(F) : 10 students

Success level: 35% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.51