Two-way vector

Photoshop Phriday: Signs Of Our Times II, by occamsmonkey
somethingawful.com
August 3, 2007

Maybe it's a tensor.

Kudos: from Physics 5A students, Spring Semester 2008

"Sorry I wasn't a more responsible student" by Student 2012
Physics 5A
May 2008
Cuesta College, San Luis Obispo, CA


"I understand the amount of work necessary" by Student 2880
Physics 5A
May 2008
Cuesta College, San Luis Obispo, CA

Kudos: from Astronomy 10 students, Spring Semester 2008

"...But was interested always" by Student 5352
Astronomy 10
May 2008
Cuesta College, San Luis Obispo, CA


"See you next semester" by Student 3512
Astronomy 10
May 2008
Cuesta College, San Luis Obispo, CA

The end of time

Sinfest, by Tatsuya Ishida
www.sinfest.net
September 17, 2007 (excerpt)

Now entering Zeno's Paradox

Photoshop Phriday: Signs Of Our Times II, by Hellkind
somethingawful.com
August 3, 2007

And yet somehow the jaywalker will reach the side of the road.

Education research: feedback on clickers (Cuesta College, Spring Semester 2008)

During Spring semester 2008, Cuesta College students taking Physics 5A (college physics, algebra-based, mandatory adjunct laboratory) at Cuesta College, San Luis Obispo, CA used numerical keypad clickers (Classroom Performance System, einstruction.com) to enter homework and to engage in peer-interaction discussion questions during lecture.

During the last week of instruction, students were given the opportunity to evaluate the instructional components of the course, and the use of clickers in an online "Learning Resource Survey" hosted by SurveyMonkey.com. Questions from section II are adapted from the Student Assessment of Learning Gains (SALG) survey (developed by Elaine Seymour, Wisconsin Center for Education Research, University of Wisconsin-Madison), and questions from section III (III.1, III.3, III.5, and III.7) were adapted from a "Clicker Attitude Survey" (N. W. Reay, Lei Bao, and Pengfei Li, Physics Education Research Group, Ohio State University).

These are the complete survey results, with some preliminary commentary. No statistical analysis was done (this was the first and only administration of this instrument), but will be forthcoming after more data has been compiled from future semesters. Values for the mean and standard deviations are given next to the modal response category for each question. Note that the order of questions within sections II and III were randomly scrambled for each student.

Learning Resource Survey
Cuesta College
Physics 5A Spring Semester 2008 sections 4987, 4988
(N = 28)

I. In order to receive credit for completing this survey, 
   first enter your four digit ID number below:
   ____


II. How much did each of the following aspects of the class help 
    your learning?

II.1 Lecture by instructor.
1. Strongly disagree      0 : 
2. Disagree               5 : *****
3. Neutral                6 : ******
4. Agree                 16 : ****************  [4.0 +/- 0.7]
5. Strongly agree         6 : ******
     
II.2 Doing assigned homework, to be entered using clickers. 
1. Strongly disagree      1 : *
2. Disagree               2 : **
3. Neutral                2 : **
4. Agree                 14 : **************  [4.0 +/- 1.0]
5. Strongly agree         9 : *********

II.3 Doing unassigned homework.
1. Strongly disagree      3 : ***
2. Disagree               1 : *
3. Neutral                8 : ********
4. Agree                 11 : ***********  [3.5 +/- 1.2]
5. Strongly agree         5 : *****

II.4 Using clickers to participate in class. 
1. Strongly disagree      0 : 
2. Disagree               2 : **
3. Neutral                3 : ***
4. Agree                 15 : ***************  [4.0 +/- 0.9]
5. Strongly agree         8 : ********

II.5 Reading the textbook.     
1. Strongly disagree      2 : **
2. Disagree               5 : *****
3. Neutral                4 : ****  [3.4 +/- 1.2]
4. Agree                 13 : *************
5. Strongly agree         4 : ****

II.6 Demonstrations/videos in class.      
1. Strongly disagree      0 : 
2. Disagree               2 : **
3. Neutral                0 : 
4. Agree                 21 : *********************  [4.0 +/- 0.7]
5. Strongly agree         5 : *****

II.7 Interacting with other students during class.   
1. Strongly disagree      0 : 
2. Disagree               0 : 
3. Neutral                7 : ******* 
4. Agree                 16 : **********  [3.9 +/- 0.7]
5. Strongly agree         5 : *****

II.8 Interacting with other students outside of class.
1. Strongly disagree      0 : 
2. Disagree               3 : ***
3. Neutral                7 : ******* 
4. Agree                 11 : ***********  [3.9 +/- 0.9]
5. Strongly agree         7 : *******

Students rated the usefulness of learning by using clickers in class (II.4), more so than any other instructional mode except for demonstrations/videos in class (II.6). Students rated doing assigned homework that was entered using clickers third highest in terms of learning usefulness, more so than lecturing by the instructor (II.1), reading the textbook (II.5), doing unassigned (but suggested) homework (II.3), and interacting with students outside (II.8) and during (II.7) class.

III. Answer the following statements which may or may not describe 
     your beliefs about the use of clickers in this class.

III.1 I like using clickers. 
1. Strongly disagree      1 : *
2. Disagree               3 : ***
3. Neutral                2 : **
4. Agree                 18 : ******************  [3.7 +/- 1.0]
5. Strongly agree         4 : ****

III.2 Clickers helped me understand lectures better.   
1. Strongly disagree      1 : *
2. Disagree               3 : ***
3. Neutral                9 : *********
4. Agree                 12 : ************  [3.5 +/- 1.0]
5. Strongly agree         3 : ***

III.3 I would recommend using clickers in future semesters of Physics 5A. 
1. Strongly disagree      2 : **
2. Disagree               2 : **
3. Neutral                1 : *
4. Agree                 17 : *****************  [3.8 +/- 1.1]
5. Strongly agree         6 : ******

III.4 I will avoid other classes using clickers in future semesters. 
1. Strongly disagree      8 : ********
2. Disagree              14 : **************  [2.0 +/- 0.9]
3. Neutral                4 : ****
4. Agree                  2 : **
5. Strongly agree         0 : 

III.5 Clickers were a positive experience.    
1. Strongly disagree      0 : 
2. Disagree               2 : **
3. Neutral                6 : ******
4. Agree                 16 : ****************  [3.8 +/- 0.8]
5. Strongly agree         4 : ****

III.6 Too much time in class was spent using clickers.   
1. Strongly disagree      2 : **
2. Disagree              16 : ****************  [2.4 +/- 0.9]
3. Neutral                6 : ******
4. Agree                  3 : ***
5. Strongly agree         1 : *

III.7 Too many clicker questions were asked. 
1. Strongly disagree      4 : ****
2. Disagree              16 : ****************  [2.3 +/- 1.0]
3. Neutral                4 : ****
4. Agree                  3 : ***
5. Strongly agree         1 : *
     
III.8 Clickers should be used to collect assigned homework. 
1. Strongly disagree      2 : **
2. Disagree               3 : ***
3. Neutral                5 : *****
4. Agree                 12 : ************  [3.6 +/- 1.2]
5. Strongly agree         6 : ******
     
III.9 Using clickers was difficult. 
1. Strongly disagree     11 : ***********
2. Disagree              13 : *************  [1.8 +/- 0.9]
3. Neutral                2 : **
4. Agree                  2 : **
5. Strongly agree         0 :

Overall, the responses in section III are positive towards the use of clickers. Although students collectively approved of the use of clickers to collect homework, a vocal minority expressed their comments below.

IV. (Optional.) Please type in any comments you may have regarding 
    the use of clickers in Physics 5A.

The following are all of the student responses to this question, verbatim and unedited.

"the clikers were very useful and i really like how their was alot of participation clicker questions. it helped out understanding the material and becuase of the clikers i felt that i was involved in the class more than other classes."

"I think that the clickers helped me to stay on the same page as the lectures. The clicker question were a good way to keep the students paying attention to the lectures."

"at first, they seemed like a pain. But after a couple of weeks using them, i realized how nice they were. I sat in the back most of the time, and it saved a lot time not having to get up to turn stuff in. sometimes it was frustrating not being able to join in a session after it had started, but that is the only draw back i see with the product."

"I like how they require you to interact with the current discussions in class. However, there are sometimes when I feel we spent too much time with them... and would have been better off seeing another example worked out on the board."

"I feel like too much time was spent using the clickers. While they might have their place for entering homework, I think we could have done more example problems and gotten more material covered with better notes had the clickers not been used."

"it sucks that when we turn in homework we dont get any partial credit or we never find out where we went wrong."

"Have a great summer P-Dog, hope to run into you in the future. 'Enjoy using clickers in your future classes.' (<- To be relevent to clickers.)"

"i still think they cost more than they are worth..."

"Clickers worked well and kept the entire class concentrated on the lecture. Clickers are also a great way to earn some participation points;)"

"We just need to focus our time on the problems, and anwering questions more effieciently and doing problem after problem until we understand"

"The only thing I don't like about the Clickers is the fact that they souldn't be used to colletct homework. I did not like the fact of spending anywhere from a half an hour to an hour on the assigned homework and not getting the correct answer after entering it with the clickers. I believe homework should have been collected by hand for partial credit for showing work. On the contrary, I enjoyed using the clickers for participation credit."

"Thanks for a great class!"

Previous posts:

• Education research: feedback on clickers (Cuesta College, Spring Semester 2008)
  Discussion of end-of-semester student opinions from the start of this past semester.
• Education research: feedback on clickers (Cuesta College, Spring Semester 2008)
  Discussion of preliminary student opinions from the start of this past semester.
• Education research: feedback on clickers (Cuesta College, Fall Semester 2007)
  Discussion of end-of-semester student opinions from a previous semester.

Education research: preliminary MPEX comparison (Cuesta College, Spring Semester 2008)

The Maryland Physics Expectations survey (MPEX) was administered to Cuesta College Physics 5A (college physics, algebra-based, mandatory adjunct laboratory) students at Cuesta College, San Luis Obispo, CA. The MPEX was given during the first week of the semester, and then on the last week of the semester, to quantify student attitudes, beliefs, and assumptions about physics using six question categories, rating responses as either favorable or unfavorable towards:

1. Independence--beliefs about learning physics--whether it means receiving information or involves an active process of reconstructing one's own understanding;
   
2. Coherence--beliefs about the structure of physics knowledge--as a collection of isolated pieces or as a single coherent system;
   
3. Concepts--beliefs about the content of physics knowledge--as formulas or as concepts that underlie the formulas;
   
4. Reality Link--beliefs about the connection between physics and reality--whether physics is unrelated to experiences outside the classroom or whether it is useful to think about them together;
   
5. Math Link--beliefs about the role of mathematics in learning physics--whether the mathematical;
   formalism is used as a way of representing information about physical phenomena or mathematics is just used to calculate numbers;
   
6. Effort--beliefs about the kind of activities and work necessary to make sense out of physics--whether they expect to think carefully and evaluate what they are doing based on available materials and feedback or not.

Cuesta College
Physics 5A Spring Semester 2008 sections 4987, 4988
(N = 29, matched pairs)
Percentage of favorable:unfavorable responses
        Overall Indep.  Coher.  Concept Real.   Math    Effort
Initial 55:17   44:13   41:27   52:19   76:05   52:14   68:10
Final   48:29   37:29   43:36   54:30   70:10   42:30   44:33

Previous posts:

• Education research: preliminary MPEX comparison (Cuesta College, Fall Semester 2007)
  (More detailed discussion on interpreting historical MPEX results at Cuesta College.)
  
• Education research: student expectations in physics
  (Background on the MPEX by E. F. Redish, J. M. Saul, and R. N. Steinberg.)

Rearview train

Rearview Train, by pvictory
Worth1000.com
Amazing Reflections and Shadows contest

1. The train may appear closer than it actually is.
2. A perfectly inelastic collision is imminent.

Physics final exam question: hot coffee plus frozen coffee

Physics 5A Final Exam, Spring Semester 2008
Cuesta College, San Luis Obispo, CA

Cf. Giambattista/Richardson/Richardson, Physics, 1/e, Problem 14.40

[20 points.] A Physics 5A student is going to make iced coffee by first brewing hot coffee, at a temperature of 85.0° C, and pouring it into a glass containing 0.300 kg of frozen coffee from a freezer at –15.0° C. How much hot coffee should the student pour into the glass, in order to result in a final temperature of 10.0° C? Assume that coffee is essentially water. Neglect the temperature change of the glass. Show your work and explain your reasoning.

(The specific heat of ice is 2.10 kJ/(kg*K); the specific heat of water is 4.19 kJ/(kg*K); the latent heat of fusion for water is 334 kJ/kg.)

Solution and grading rubric:

• p = 20/20:
  Correct. Net heat exchange with the environment (or glass) is set to zero, and equates this to sum of the heat taken in by the ice to warm up from -15.0 degrees C to 0 degrees C, the heat taken in to melt this ice completely, the heat taken in by the melted ice (as water) to warm up from 0 degrees C to 10 degrees C, and the heat given up by the coffee to cool down from 85.0 degrees C to 10.0 degrees C. Solves for the mass of the hot coffee, which is 0.389 kg.
  
• r = 16/20:
  Nearly correct, but includes minor math errors. May neglect the specific heat capacity for ice and water being different, or may have converted temperature changes in Celsius into absolute temperatures in Kelvins.
  
• t = 12/20:
  Nearly correct, but approach has conceptual errors, and/or major/compounded math errors. At least has energy balance equation with systematic application of Q = m*c*delta(T) and Q = m*L heat exchanges.
  
• v = 8/20:
  Implementation of right ideas, but in an inconsistent, incomplete, or unorganized manner.
  
• x = 4/20:
  Implementation of ideas, but credit given for effort rather than merit.
  
• y = 2/20:
  Irrelevant discussion/effectively blank.
  
• z = 0/20:
  Blank.
  

Grading distribution:
p: 3 students
r: 3 students
t: 10 students
v: 15 students
x: 0 students
y: 1 student
z: 0 students

A sample of a "p" response (from student 1484) is shown below:
An "r" response (from student 7937) that uses the same heat capacity for ice and for liquid coffee:
An "x" response (from student 1337) that ends on a friendly note:

Physics final exam question: cable, boom, and load

Physics 5A Final Exam, spring semester 2008
Cuesta College, San Luis Obispo, CA

Cf. Giambattista/Richardson/Richardson, Physics, 1/e, Problem 8.37

[20 points.] A uniform beam and sign are suspended using a cable that has a breaking strength of 200.0 N, as shown at right. The sign has a weight of 150.0 N and the beam's weight is 60.0 N. The beam's length is 2.00 m and the sign is a square 1.00 m on each side. What is the minimum angle theta allowed between the beam and cable? Show your work and explain your reasoning.

Solution and grading rubric:

• p = 20/20:
  Correct. In order for the beam and sign to be suspended, the net torque on this system must be zero, and equates this to the sum of the torques of the weight of the beam and sign, and the torque of the cable (using the left end of the beam as the origin). Solves for the minimum angle allowed, which is 45.4 degrees.
  
• r = 16/20:
  Nearly correct, but includes minor math errors. May have mismeasured a lever arm.
  
• t = 12/20:
  Nearly correct, but approach has conceptual errors, and/or major/compounded math errors. At least has net torque equation set to zero, but problematic calculation of individual torques.
  
• v = 8/20:
  Implementation of right ideas, but in an inconsistent, incomplete, or unorganized manner. Some systematic approach at calculating individual torque terms.
  
• x = 4/20:
  Implementation of ideas, but credit given for effort rather than merit.
  
• y = 2/20:
  Irrelevant discussion/effectively blank.
  
• z = 0/20:
  Blank.
  

Grading distribution:
p: 4 students
r: 7 students
t: 3 students
v: 12 students
x: 2 students
y: 1 student
z: 2 students

A sample of a "p" response (from student 1468) that keeps it short and simple is shown below:
An "r" response (from student 6867) with an error in a lever arm:
A rather flippant "x" response (from student 1337):

Physics final exam question: bullet embedding in block

Physics 5A Final Exam, Spring Semester 2008
Cuesta College, San Luis Obispo, CA

Cf. Giambattista/Richardson/Richardson, Physics, 1/e, Problem 7.44

[20 points.] A 0.075 kg bullet is shot horizontally and collides with a 2.00 kg block of wood that is initially stationary. The bullet embeds in the block and the block slides along a horizontal surface for 1.25 m. The coefficient of kinetic friction between the block and surface is 0.400. Determine the original speed of the bullet. Show your work and explain your reasoning.

Solution and grading rubric:

• p = 20/20:
  Correct. The collision between the bullet and block is a perfectly inelastic collision, and uses conservation of momentum to relate the initial velocity v_1,i of the bullet with the final velocity of the bullet-block system v_12,f. As the bullet-block system slides across the surface, applies energy conservation to relate the amount of kinetic energy contained in v_12,f with the negative work done by kinetic friction. Finds that v_12,f = 3.13 m/s, and v_1,i = 86.6 m/s.
  
• r = 16/20:
  Nearly correct, but includes minor math errors. At least systematically divides problem into momentum conservation and energy conservation segments, and serious attempt at connecting information and reduction of unknowns between the momentum and energy conservation equations.
  
• t = 12/20:
  Nearly correct, but approach has conceptual errors, and/or major/compounded math errors. Typically has one conservation law applied on a systematic manner, the other is problematic or missing.
  
• v = 8/20:
  Implementation of right ideas, but in an inconsistent, incomplete, or unorganized manner. Only one conservation law applied, and in a problematic manner (or equivalent amount of constructive effort).
  
• x = 4/20:
  Implementation of ideas, but credit given for effort rather than merit.
  
• y = 2/20:
  Irrelevant discussion/effectively blank.
  
• z = 0/20:
  Blank.
  

Grading distribution:
p: 2 students
r: 5 students
t: 7 students
v: 15 students
x: 3 students
y: 1 student
z: 0 students

A sample of a "p" response (from student 7937) is shown below:
A nearly correct attempt (from student 6867) is a sample of an "r" response:
A "v" response (from student 6788) has a "WTF" ("what to find") moment:

Physics final exam question: box sliding down inclined board

Physics 5A Final Exam, Spring Semester 2008
Cuesta College, San Luis Obispo, CA

Cf. Giambattista/Richardson/Richardson, Physics, 1/e, Comprehensive Problem 4.146

[20 points.] The coefficient of static friction between a 2.50 kg box and a wooden board is 0.45 and the coefficient of kinetic friction between the box and the board is 0.28. The box is placed on the board, which is slowly lifted at one end until the box starts to slide down the board, at which point the angle theta of the board is held constant. Determine the angle theta of the board, and the acceleration of the box as it slides down the board. Show your work and explain your reasoning.


Solution and grading rubric:

• p = 20/20:
  Correct. At the angle where static friction is (about to be) overwhelmed, it is equal to the x-component of weight, and Newton's first law is used to determine that the angle theta = 24.2 degrees. At this angle, kinetic friction acts on box, and Newton's second law is used to find that the acceleration of the box is 1.52 m/s^2 down along the ramp.
  
• r = 16/20:
  Nearly correct, but includes minor math errors. Correct angle for ramp, but acceleration has minor problems, such as kinetic friction being the only force acting along the x-direction in Newton's second law, or divides by g instead of by mass on both sides of Newton's second law.
  
• t = 12/20:
  Nearly correct, but approach has conceptual errors, and/or major/compounded math errors. Angle of board is wrong, but accounts for both kinetic friction and the x-component of weight acting on the box in Newton's second law. Or determines correct angle of board, but nothing much further than that.
  
• v = 8/20:
  Implementation of right ideas, but in an inconsistent, incomplete, or unorganized manner. Some systematic attempt at both the (limiting) static and accelerating case.
  
• x = 4/20:
  Implementation of ideas, but credit given for effort rather than merit.
  
• y = 2/20:
  Irrelevant discussion/effectively blank.
  
• z = 0/20:
  Blank.
  

Grading distribution:
p: 3 students
r: 4 students
t: 9 students
v: 9 students
x: 7 students
y: 1 student
z: 0 students

A sample of a "p" response (from student 6154) is shown below:
An "r" response (from student 2012), where the sine and cosine components were inadvertently switched, but following results were essentially correct:
Another "r" response (from student 5711), where at the last step, g is divided from both sides of Newton's second law, instead of m:
A "t" response (from student 2880), where only the angle of the board is found:

Physics final exam question: molar specific heats of gases

Physics 5A Final Exam, Spring Semester 2008
Cuesta College, San Luis Obispo, CA

Cf. Giambattista/Richardson/Richardson, Physics, 1/e, Conceptual Question 14.14

[10 points.] Which has the greater molar specific heat—a diatomic gas such as N2, or a monatomic gas such as Ne? Explain your answer using the properties of the specific heats of ideal gases.

Solution and grading rubric:

• p = 10/10:
  Correct. A (rigid-bond) diatomic gas molecule can have three modes of translational kinetic energy, as well as two rotation modes, whereas a monoatomic gas atom can only have the three translation kinetic energy modes. Thus a diatomic gas molecule can take in more heat than a monatomic gas atom to produce a given increase in temperature (which is related to an increase in translational kinetic energy).
  
• r = 8/10:
  As (p), but argument indirectly, weakly, or only by definition supports the statement to be proven, or has minor inconsistencies or loopholes. At least has some discussion of the different number of modes in equipartition.
  
• t = 6/10:
  Nearly correct, but argument has conceptual errors, or is incomplete. States that C_V = (5/2)*R for diatomic gas molecules, and C_V = (3/2)*R for monatomic gas atoms, with no discussion of equipartition/modes.
  
• v = 4/10:
  Limited relevant discussion of supporting evidence of at least some merit, but in an inconsistent or unclear manner. May state correct answer with no discussion, or incorrect answer motivated by complexity, molar mass, presence of a bond, relative bond strengths, etc.
  
• x = 2/10:
  Implementation/application of ideas, but credit given for effort rather than merit.
  
• y = 1/10:
  Irrelevant discussion/effectively blank.
  
• z = 0/10:
  Blank.
  

Grading distribution:
p: 2 students
r: 6 students
t: 10 students
v: 14 students
x: 0 students
y: 1 student
z: 0 students

A sample of a "p" response (from student 1337) is shown below:

A "t" response (from student 1024) where only the correct values for the molar specific heats are cited:

Physics final exam question: loosening a jar lid

Physics 5A Final Exam, Spring Semester 2008
Cuesta College, San Luis Obispo, CA

Cf. Giambattista/Richardson/Richardson, Physics, 1/e, Conceptual Question 13.6

[10 points.] One way to loosen the metal lid on a glass jar is to run it under very hot water. Explain how this works using the properties of heat transfer and thermal expansion.

Solution and grading rubric:

• p = 10/10:
  Correct. As heat is transferred to the metal lid and glass jar, both of them undergo thermal expansion. However, the material in the lid must have a greater coefficient of thermal expansion than glass, in order to expand more and loosen in relation to the opening of the jar.
  
• r = 8/10:
  As (p), but argument indirectly, weakly, or only by definition supports the statement to be proven, or has minor inconsistencies or loopholes. Does not take in account that the glass jar must expand less (or negligibly so) relative to the metal lid in order for it to loosen.
  
• t = 6/10:
  Nearly correct, but argument has conceptual errors, or is incomplete.
  
• v = 4/10:
  Limited relevant discussion of supporting evidence of at least some merit, but in an inconsistent or unclear manner. Explanation may actually result in lid being tighter on jar, or motivates contents under higher pressure will loosen the lid.
  
• x = 2/10:
  Implementation/application of ideas, but credit given for effort rather than merit.
  
• y = 1/10:
  Irrelevant discussion/effectively blank.
  
• z = 0/10:
  Blank.
  

Grading distribution:
p: 10 students
r: 16 students
t: 1 students
v: 5 students
x: 0 students
y: 1 student
z: 0 students

A sample of a "p" response (from student 5711) is shown below:
A somewhat strange "v" response (from student 1024) that does result in loosening the lid is claimed to be caused by the glass jar contracting in size:

"You don't know anything."

College, by Dan Killeen
As published in The California Aggie (University of California, Davis)
Ca. 1993

The trials and tribulations of IB--Idiot Boy.

There's one in every class.

(Dan Killeen's current strip is Steve, at dankilleen.com.)

Education research: SATA results (Cuesta College, Spring Semester 2008)

Student attitudes were assessed using the Survey of Attitudes Towards Astronomy (SATA), a 34-question, five-point Likert scale questionnaire that measures four attitude subscales (Zeilik & Morris, 2003):

• Affect (positive student attitudes towards astronomy and science);
  
• Cognitive competence (students' self-assessment of their astronomy/science knowledge and skills);
  
• Difficulty (reverse-coded such that high-difficulty corresponds to a rating of 1, low-difficulty assessment of astronomy/science corresponds to a rating of 5);
  
• Value (students' assessment of the usefulness, relevance, and worth of astronomy/science in personal and professional life).

The SATA was administered as a pre-test on the first day of class, and as a post-test on the last day of class.

Cuesta College
Astronomy 10 Spring Semester 2008 section 4160
(N = 30, matched pairs only)
        Affect       Cogn. Comp.  Difficulty   Value
Initial 3.7 +/- 0.6  3.6 +/- 0.4  3.7 +/- 0.4  2.5 +/- 0.4
Final   3.8 +/- 0.7  3.6 +/- 0.7  3.7 +/- 0.4  2.6 +/- 0.6

Cuesta College
Astronomy 10 Spring Semester 2008 section 5166
(N = 43, matched pairs only)
        Affect       Cogn. Comp.  Difficulty   Value
Initial 3.6 +/- 0.6  3.5 +/- 0.5  3.7 +/- 0.5  2.7 +/- 0.5
Final   3.5 +/- 0.7  3.4 +/- 0.7  3.5 +/- 0.6  2.8 +/- 0.6

Apparently no statistically significant differences between the pre-test and post-test results for each section.

References, and more detailed discussion on previous semesters' results:
Education research: SATA results (Cuesta College, Fall Semester 2007).

Astronomy final exam question: countering Drake equation pessimism

Astronomy 10 Final Exam, Spring Semester 2008
Cuesta College, San Luis Obispo, CA

Astronomy 10 learning goal F.2

[15 points.] The Drake equation can be used to show that Earth is the only advanced technological civilizations in the Milky Way. Discuss a plausible argument against this unreasonably pessimistic result.

Solution and grading rubric:

• p = 15/15:
  Correct. Discusses in some form how a null result cannot disprove a hypothesis, the Mediocrity Principle/Copernicanism, the Scale Argument, or any sound, principled, reasonable argument against overly pessimistic results from the Drake equation.
  
• r = 12/15:
  Nearly correct (explanation weak, unclear or only nearly complete); includes extraneous/tangential information; or has minor errors.
  
• t = 9/15:
  Contains right ideas, but discussion is unclear/incomplete or contains major errors. Argues uncertain, unproven characteristics ("SWAG") of Drake equation components, or instead cites arguments against unreasonably optimisitic results.
  
• v = 6/15:
  Limited relevant discussion of supporting evidence of at least some merit, but in an inconsistent or unclear manner.
  
• x = 3/15:
  Implementation/application of ideas, but credit given for effort rather than merit.
  
• y = 1.5/15:
  Irrelevant discussion/effectively blank.
  
• z = 0/15:
  Blank.
  

Grading distribution:
Section 4160
p: 19 students
r: 0 students
t: 13 students
v: 2 students
x: 0 students
y: 1 student
z: 0 students

Section 5166
p: 30 students
r: 2 students
t: 6 students
v: 1 student
x: 0 students
y: 1 student
z: 0 students

A sample "p" response (from student 4024):
Another "p" response (from student 1337):
A "p" response (from student 1379) with a nice afterword:
Yet another "p" response (from student 1886) with a nice afterword:
Student 3635 goes for the "y" response:

Astronomy final exam question: dark energy properties and evidence

Astronomy 10 Final Exam, Spring Semester 2008
Cuesta College, San Luis Obispo, CA

Astronomy 10 learning goal 12.3

[15 points.] Describe the properties of dark energy, and explain the observational evidence for its existence.

Solution and grading rubric:

• p = 15/15:
  Correct. Distant type Ia supernovae are dimmer than expected from their redshifts, which means that the expansion of the universe today is different (faster) now than back then. Dark energy is the proposed agent of this acceleration, and produces a "pressure" that accelerates the expansion rate of the universe, and is itself produced by space itself, resulting in more dark energy as space expands.
  
• r = 12/15:
  Nearly correct (explanation weak, unclear or only nearly complete); includes extraneous/tangential information; or has minor errors. Only correctly describes properties of dark energy, or only correctly describes the observational evidence for the existence of dark energy.
  
• t = 9/15:
  Contains right ideas, but discussion is unclear/incomplete or contains major errors. Typically claims dark energy causes the expansion of the universe (it is causing the recent acceleration of the expansion of the universe), or had caused the inflation which happened just after recombination.
  
• v = 6/15:
  Limited relevant discussion of supporting evidence of at least some merit, but in an inconsistent or unclear manner. Confuses dark energy with dark matter, scalar field energy, etc.
  
• x = 3/15:
  Implementation/application of ideas, but credit given for effort rather than merit.
  
• y = 1.5/15:
  Irrelevant discussion/effectively blank.
  
• z = 0/15:
  Blank.
  

Grading distribution:
Section 5166
p: 1 student
r: 5 students
t: 4 students
v: 26 students
x: 3 students
y: 1 student
z: 0 students

A sample "p" response (from student 2431):
Student 1886 wanders off-topic from dark energy by including details about dark matter, for an "r" response:
Student 1426 at least remembers the story behind dark energy being a "sexy" placeholder name for whatever it is that is accelerating the expansion of space, for an "x" response:
Student 2743 has another example of an "x" response that has a good start, but ends abruptly before the magic can begin:
An "x" response (from student 7499) attempts to appeal to the obvious:
Student 3635 is a race to the bottom, earning a "y" response:

Astronomy final exam question: dark matter properties and evidence

Astronomy 10 Final Exam, Spring Semester 2008
Cuesta College, San Luis Obispo, CA

Astronomy 10 learning goal 11.3

[15 points.] Describe the properties of dark matter, and explain the observational evidence for its existence.

Solution and grading rubric:

• p = 15/15:
  Correct. The orbital speeds of stars are nearly the same for all distances from the center of the Milky Way, instead of decreasing with increasing distance. This is due to the mass of the Milky Way not being concentrated at the very center (despite a supermassive black hole there), but being diffusely distributed above and below the disk of the Milky Way. Because this amount of mass is not visible in a manner such as luminous stars and gas, this unseen mass is termed "dark matter." May also discuss properties of WIMPs and MaCHOs, the latter of which has been observed due to gravitational lensing.
  
• r = 12/15:
  Nearly correct (explanation weak, unclear or only nearly complete); includes extraneous/tangential information; or has minor errors. Only correctly describes properties of dark matter, or only correctly describes the observational evidence for the existence of dark matter.
  
• t = 9/15:
  Contains right ideas, but discussion is unclear/incomplete or contains major errors. At least identifies dark matter as being in the halo of the Milky Way.
  
• v = 6/15:
  Limited relevant discussion of supporting evidence of at least some merit, but in an inconsistent or unclear manner. Confuses dark matter with dark nebulae, dark energy, etc.
  
• x = 3/15:
  Implementation/application of ideas, but credit given for effort rather than merit.
  
• y = 1.5/15:
  Irrelevant discussion/effectively blank.
  
• z = 0/15:
  Blank.
  

Grading distribution:
Section 4160
p: 7 students
r: 6 students
t: 6 students
v: 13 students
x: 2 students
y: 1 student
z: 0 students

A sample "p" response (from student 1721) ponders the MaCHos versus WIMPs debate:
Another "p" response, from student 6221 discusses the gravitational lensing evidence for dark matter:
Student 7045 gives a "p" response discussing how Kepler's third law is apparently violated by the gravitational properties of dark matter:
An "x" response from student 0501 appeals to a perceived duality of dark matter and luminous matter:
Student 0223 goes for the whimsical "y" response:

Astronomy final exam question: halo cluster vs. disk star age

Astronomy 10 Final Exam, Spring Semester 2008
Cuesta College, San Luis Obispo, CA

Astronomy 10 learning goal 11.5

[15 points.] Discuss the evidence that stars in the halo clusters of the Milky Way are older than stars in the disk of the Milky Way.

Solution and grading rubric:

• p = 15/15:
  Correct. Halo cluster stars are known to be older because there are no massive stars left on the main sequence, and their spectra are metal-poor; in contrast to the stars in the disk of the Milky Way, of which there are many massive stars on the main sequence (thus formed relatively recently), and their spectra are metal-rich (heavy elements from past type II supernovae).
  
• r = 12/15:
  Nearly correct (explanation weak, unclear or only nearly complete); includes extraneous/tangential information; or has minor errors. Cites plausible, but somewhat less convincing evidence (e.g., massive stars are only found in the disk of the Milky Way).
  
• t = 9/15:
  Contains right ideas, but discussion is unclear/incomplete or contains major errors. Uses argument that Milky Way evolved from spherical- to disk-shaped, when in fact this theory of evolution is based on the fact that halo cluster stars are older than disk stars (due to the reasons cited in (p)).
  
• v = 6/15:
  Limited relevant discussion of supporting evidence of at least some merit, but in an inconsistent or unclear manner.
  
• x = 3/15:
  Implementation/application of ideas, but credit given for effort rather than merit.
  
• y = 1.5/15:
  Irrelevant discussion/effectively blank.
  
• z = 0/15:
  Blank.
  

Grading distribution:
Section 4160
p: 7 students
r: 6 students
t: 6 students
v: 13 students
x: 2 students
y: 1 student
z: 0 students

Section 5166
p: 4 students
r: 1 student
t: 10 students
v: 21 students
x: 0 students
y: 2 students
z: 0 students

A sample "p" response (from student 1721):
Student 1882 gets a "x" for circular reasoning:
Student 0000 gets a "y" for begging the question:
Student 1337 gets a "y" for a display of artistic skill:

Lolcat: Astro Cat

"Astro Cat Will Play for you the Symphony of Space" by Shauna! >^.^YTMND
icanhascheezburger.com
February 22, 2007

The apparently original photo is found below, as retrieved from mirror.waffleimages.com: