20090630

Astronomy in the marketplace: star party beer!

20090627197
http://www.flickr.com/photos/waiferx/3668359867/
Originally uploaded by Waifer X

Stargazer India Pale Ale bottle, BevMo!, San Luis Obispo, CA. Photo by Cuesta College Physical Sciences Division instructor Dr. Patrick M. Len, with a Nokia e71 smartphone.

20090629

Astronomy in the marketplace: Rare Earth hypothesis?

20090627195
http://www.flickr.com/photos/waiferx/3668358953/
Originally uploaded by Waifer X

Rare Earth cabernet sauvignon wine bottle, BevMo!, San Luis Obispo, CA. Photo by Cuesta College Physical Sciences Division instructor Dr. Patrick M. Len, with a Nokia e71 smartphone.

20090628

Non sequitur: bee!

20090621165
http://www.flickr.com/photos/waiferx/3668307249/
Originally uploaded by Waifer X

Bee! Green Acres Lavender Farm, Atascadero, CA. Photo by Cuesta College Physical Sciences Division instructor Dr. Patrick M. Len, with a Nokia e71 smartphone.

20090626

Bon mots: success and failure

"One essential to success is that your desire be an all-obsessing one, your thoughts and aims be co-ordinated, and your energy be concentrated and applied without letup."
--Claude M. Bristol

"If the day and the night are such that you greet them with with joy, and life emits a fragrance like flowers and sweet-scented herbs, more elastic, more starry, more immortal--that is your success."
--Henry David Thoreau

"Many of life's failures are experienced by people who did not realize how close they were to success when they gave up."
--Thomas Edison

"Success is the ability to go from one failure to another with no loss of enthusiasm."
--Sir Winston Churchill

"Failure is the condiment that gives success its flavor."
--Truman Capote

"The toughest thing about success is that you've got to keep on being a success."
--Irving Berlin

"Success is the point of self-deception. Failure is the point of self-knowledge."
--Graham Greene

"I am a success today because I had a friend who believed in me, and I didn't have the heart to let him down."
--Abraham Lincoln

"Failure is not the only punishment for laziness; there is also the success of other."
--Jules Renard

"If there is any great secret of success in life, it lies in the ability to put yourself in the other's place and to see things from his point of view--as well as your own."
--Henry Ford

"In most things success depends on knowing how long it takes to succeed."
--Charles Louis de Montesquieu

"Success is more permanent when you achieve it without destroying your principles."
--Walter Cronkite

"Success requires first expending ten units of effort to produce one unit of results. Your momentum will then produce ten units of results with each unit of effort."
--Givens, Charles J.

"Success isn't permanent and failure isn't fatal."
--Mike Ditka

"Success is a lousy teacher. It seduces smart people into thinking they can't lose."
--Bill Gates

"I cannot give you the formula for success, but I can give you the formula for failure--which is: Try to please everybody."
--Herbert Bayard Swope

"Failure is not the only punishment for laziness; there is also the success of others."
--Jules Renard

"Failure is instructive. The person who really thinks learns quite as much from his failures as from his successes."
--John Dewey

"Success is to be measured not so much by the position that one has reached in life as by the obstacles which he has overcome while trying to succeed."
--Booker T. Washington

"One does not get anywhere simply by going over the success again and again, whereas by talking over the difficulties people can hope to make some progress."
--P. A. M. Dirac

"In order to succeed, your desire for success should be greater than your fear of failure."
--Bill Cosby

"As long as an experiment yields data, it's a success."
--Adam Savage

"If at first you don't succeed, destroy all evidence that you tried."
--Steven Wright

"It is possible to fail in many ways, while to succeed is possible only in one way."
--Aristotle

"Fail again. Fail better."
--Samuel Beckett

"Let us be thankful for the fools. But for them the rest of us could not succeed."
--Mark Twain

"If you want to succeed, double your failure rate."
--Thomas Watson, founder of IBM

"If at first you don't succeed, failure may be your style."
--Quentin Crisp

"At first you don't succeed, try, try again. Then quit. There's no point in being a damn fool about it."
--W.C. Fields

"If at first you don't succeed, remove all evidence that you have ever tried."
--Ricky Gervais

"It is better to fail in originality than to succeed in imitation."
--Herman Melville

"I've missed more than 9,000 shots in my career. I've lost almost 300 games. Twenty-six times, I've been trusted to take the game winning shot and missed. I've failed over and over and over again in my life. And that is why I succeed."
--Michael Jordan

"Ninety-nine percent of failures come from people who have the habit of making excuses."
--George Washington Carver

"Failure is unimportant. It takes courage to make a fool of yourself."
--Charlie Chaplin

"When ideas fail, words come in very handy."
--Johann Wolfgang von Goethe

"This thing we call 'failure' is not the falling down, but the staying down."
--Mary Pickford

"Failure is only the opportunity to begin again more intelligently."
--Henry Ford

"There are two kinds of failure: those who thought and never did, and those who did and never thought."
--Laurence J. Peter

"The big failures aren't data failures; they aren't issues of 'We don't know.' They're issues of 'We don't want to make the effort to be rigorous.'"
--Dan diBartolomeo

"It is common sense to take a method and try it. If it fails, admit it frankly and try another. But above all, try something."
--Franklin Delano Roosevelt

"It is not enough to succeed, others must fail."
--Francois De La Rochefoucauld

"The surest way to fail is not to determine to succeed."
--Richard Brinsley Sheridan

20090625

Found physics: thermal volume expansion

20090621165
http://www.flickr.com/photos/waiferx/3656904465/
Originally uploaded by Waifer X

Volume expansion disclaimer, Costco fuel pump, San Luis Obispo, CA. Photo by Cuesta College Physical Sciences Division instructor Dr. Patrick M. Len.

20090624

Found physics: accelerating carbonation bubbles

20090621165
http://www.flickr.com/photos/waiferx/3656904227/
Originally uploaded by Waifer X

Rising carbonation bubbles in Wider's pear cider, Black Sheep Bar & Grill, San Luis Obispo, CA. Assuming that bubbles are forming and being released at regular time intervals at nucleation sites, increasing space between bubbles indicates acceleration (due to the bouyant force and Newtonian fluid forces, etc.). Photo by Cuesta College Physical Sciences Division instructor Dr. Patrick M. Len.

20090621

Education research: student flashcard responses

090128-1070926
http://www.flickr.com/photos/waiferx/3585909451/
Originally uploaded by Waifer X

Astronomy 210 students at Cuesta College using flashcards in a peer instruction ("think-pair-share") interactive learning environment. Instructor sees feedback from student responses to a multiple-choice question; if responses are only 30%-70% correct, then students are given "about a minute" to explain to a neighboring student why they chose their response, before responding with flashcards again. Sample instructor dialog is discussed in a previous post. Video by Cuesta College Physical Sciences division instructor Dr. Patrick M. Len.

Links to the full-size front and backs of these cards (to be folded over by the students and held under their chin to respond) are posted below:


20090620

Infrared and ultraviolet light, made visible

090529-1090773
http://www.flickr.com/photos/waiferx/3577304878/
Originally uploaded by Waifer X

Flickering infrared beam from DVD remote, while not visible to the naked eye, is detectable with a charged-coupled device (CCD) found in digital cameras. Video by Cuesta College Physical Sciences Division instructor Dr. Patrick M. Len.


090529-1090772
http://www.flickr.com/photos/waiferx/3577276128/
Originally uploaded by Waifer X

"Invisible" ink puzzle on the back of a Milky Way bar Star Wars promotional package, normally not visible to the naked eye, but made visible when illuminated by an ultraviolet lamp, causing the ink to fluoresce in the visible spectrum. Video by Cuesta College Physical Sciences Division instructor Dr. Patrick M. Len.

20090619

TireWriter(TM): spiral arm formation model

090421-1080882
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.

20090618

Cuesta College star parties (San Luis Obispo campus, North County campus)

20090429108
http://www.flickr.com/photos/waiferx/3567637614/
Originally uploaded by Waifer X

Waxing crescent Moon, taken with a Nokia e71 smartphone through the 14" reflector at the Bowen Obsevatory atop the Building 2400 Science Forum, on campus at Cuesta College, San Luis Obispo, CA. Photo by Cuesta College Physical Sciences Division instructor Dr. Patrick M. Len.


090430-1080966
http://www.flickr.com/photos/waiferx/3567639114/
Originally uploaded by Waifer X

Waxing crescent Moon, taken with a handheld Panasonic Lumix DMC-LZ8 through a 10" Newtonian reflector at a Cuesta College North County Campus star party, Paso Robles, CA. Photo by Cuesta College Physical Sciences Division instructor Dr. Patrick M. Len.


090430-1080969
http://www.flickr.com/photos/waiferx/3567641398/
Originally uploaded by Waifer X

Cuesta College Physical Sciences division instructor Dr. Patrick M. Len (L), and Astronomy 210L students and guests from both North County and San Luis Obispo campuses during the end-of-semester North County campus star party.

20090617

Central Coast Astronomical Society monthly meeting: Cal Poly meteorite collection

090423-1080884
http://www.flickr.com/photos/waiferx/3566822715/
Originally uploaded by Waifer X

090423-1080885
http://www.flickr.com/photos/waiferx/3567636770/
Originally uploaded by Waifer X

California Polytechnic State University Physics Department professor Dr. John Keller gives a presentation on meteorite (and meteorwrong) samples at a monthly Central Coast Astronomical Society meeting held on campus at Cuesta College, San Luis Obispo, CA. Photo by Cuesta College Physical Sciences Division instructor Dr. Patrick M. Len.


090423-1080887
http://www.flickr.com/photos/waiferx/3586244186/
Originally uploaded by Waifer X

Acid-etched iron meteorite slice, revealing the characteristic Widmanstatten pattern, indicative of slow cooling and crystallization within the iron-nickel cores of larger asteroids. Note the "vug" inclusion on the middle left of the slice. From the California Polytechnic State University Physics Department meteorite collection, presented at the April 2009 meeting of the Central Coast Astronomical Society. Photo by Cuesta College Physical Sciences Division instructor Dr. Patrick M. Len.

20090616

Kudos: physics is awesome like that!

"Physics is awesome like that!" by Student 4974
Physics 205A
May 2009
Cuesta College, San Luis Obispo, CA

The teapot mentioned here is reference to a Physics 205A final exam problem.

20090615

Kudos: to be honest...

"To be honest I am not sure how to go about solving this problem..." by Student 4284
Physics 205A
May 2009
Cuesta College, San Luis Obispo, CA

20090614

Physics final exam problem: hot bullet into ice block

Physics 205A Final Exam, Spring Semester 2009
Cuesta College, San Luis Obispo, CA

Cf. Giambattista/Richardson/Richardson, Physics, 2/e, Comprehensive Problem 14.102

[20 points.] A 0.44 kg lead slug leaves a rifle at a temperature of 155 degrees C and travels at a speed of 190 m/s until it hits a 20.0 kg block of ice at 0 degrees C and comes to a rest within it. Determine how much ice will melt. Show your work and explain your reasoning.

(Specific heat of lead is 0.13 kJ/(kg*K); specific heat of ice is 2.1 kJ/(kg*K); latent heat of fusion for water is 333.7 (kJ/kg) ; specific heat of water is 4.19 kJ/(kg*K).)

Solution and grading rubric:
  • p = 20/20:
    Correct. The kinetic energy of the bullet that is lost (7,942 J) as it comes to a complete stop, along with the heat it gives up as it cools down to 0 degrees C (8,866) is equal to the heat absorbed by the ice as it melts (16,808 J), and the resulting mass of ice melting is found to be 0.0504 kg.
  • r = 16/20:
    Nearly correct, but includes minor math errors.
  • t = 12/20:
    Nearly correct, but approach has conceptual errors, and/or major/compounded math errors. Does not include the kinetic energy of the bullet.
  • 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:
Sections 30880, 30881
p: 2 students
r: 5 students
t: 22 students
v: 9 students
x: 0 students
y: 0 students
z: 1 student

A sample "p" response (from student 5225):

A sample "r" response (from student 0008), with a kJ to J conversion error:

Another sample "r" response (from student 1830), with similar kJ to J conversion errors, but no explicit calculation for the amount of ice melted:

Another sample "r" response (from student 1990), with similar kJ to J conversion errors, coming to the conclusion that the entire ice block would melt:

Another sample "r" response (from student 6447), again with similar kJ to J conversion errors and concluding that the entire ice block would melt:

A sample "t" response (from student 1807), with no kinetic energy of the bullet:

Another sample "t" response (from student 1991), again with no kinetic energy of the bullet:

20090613

Physics final exam problem: block sliding downhill into spring

Physics 205A Final Exam, spring semester 2009
Cuesta College, San Luis Obispo, CA

Cf. Giambattista/Richardson/Richardson, Physics, 2/e, Comprehensive Problem 6.87

A 0.45 kg block is 1.20 m above the base of a slope, where it starts with an initial speed. At the bottom of the slope is a horizontal k = 60 N/m spring, which is compressed by 0.55 m from equilibrium when the block comes (momentarily) to a stop. What was the initial speed of the block? Neglect friction and drag. Show your work and explain your reasoning using the properties of energy conservation.

Solution and grading rubric:
  • p:
    Correct. Sets up an energy conservation equation with changes in gravitational potential energy, translational kinetic energy, and elastic potential energy summing to zero (as there is no non-conservative work), and solves for the initial speed of the block.
  • r:
    Nearly correct, but includes minor math errors. Typically forgets to square quadratic terms, or has sign error.
  • t:
    Nearly correct, but approach has conceptual errors, and/or major/compounded math errors. At least applies energy conservation, but with non-conservative work done, a missing energy term, etc.
  • v:
    Implementation of right ideas, but in an inconsistent, incomplete, or unorganized manner. Calculations of energy terms, but does not tie them together in an energy conservation equation.
  • x:
    Implementation of ideas, but credit given for effort rather than merit. Approach involving methods other than energy conservation.
  • y:
    Irrelevant discussion/effectively blank.
  • z:
    Blank.

Grading distribution:
Sections 30880, 30881
p: 10 students
r: 11 students
t: 7 students
v: 7 students
x: 4 students
y: 0 students
z: 0 students

A sample "p" response (from student 1990):
A sample "r" response (from student 0506), with a sign error for -9.80 m/s2 (which should be positive in calculating scalar quantities such as gravitational potential energy):
Another sample "r" response (from student 2411), with two sign errors:
Another sample "r" response (from student 4278), forgetting to square the quadratic terms for spring potential energy:
A sample v" response (from student 4444), with a plea for clemency, but at least demonstrating some attempt at applying energy conservation concepts:

20090612

Physics final exam problem: sliding and falling string-connected boxes

Physics 205A Final Exam, spring semester 2009
Cuesta College, San Luis Obispo, CA

Cf. Giambattista/Richardson/Richardson, Physics, 2/e, Problem 4.87

Consider a 5.0 kg box on a horizontal table, which is not frictionless. A second box of mass 2.0 kg hangs from an ideal cord of negligible mass that runs over an ideal pulley and then is connected to the 5.0 kg box. The boxes are released from rest, and accelerate at a rate of 1.6 m/s2. What is the magnitude of the kinetic friction force on the 5.0 kg box? Show your work and explain your reasoning using free-body diagram(s), the properties of forces, and Newton's laws.

Solution and grading rubric:
  • p:
    Correct. Isolates 5.0 kg and 2.0 kg boxes by drawing free-body diagrams for each, and applies Newton's second law to each box. Finds that the upwards tension force on the 2.0 kg box is 16.4 N (which is equal in magnitude to the rightwards tension force on the 5.0 kg box, from Newton's third law). Thus the leftwards kinetic friction force on the 5.0 kg box must be 8.4 N. (May also use a combined 7.0 kg box with only weight and kinetic friction acting on opposite directions on it.)
  • r:
    Nearly correct, but includes minor math errors.
  • t:
    Nearly correct, but approach has conceptual errors, and/or major/compounded math errors. Applies Newton's first law instead of Newton's second law to the 2.0 kg box, effectively making the tension force 19.6 N.
  • v:
    Implementation of right ideas, but in an inconsistent, incomplete, or unorganized manner. Some application of Newton's laws to forces shown on free-body diagrams.
  • x:
    Implementation of ideas, but credit given for effort rather than merit. Approach involving methods other than application of Newton's laws.
  • y:
    Irrelevant discussion/effectively blank.
  • z:
    Blank.

Grading distribution:
Sections 30880, 30881
Exam code: finalDe4f
p: 3 students
r: 2 students
t: 17 students
v: 10 students
x: 6 students
y: 1 student
z: 0 students

A sample "p" response (from student 0915), treating the 5.0 kg box and 2.0 kg box as separate objects:
Another sample "p" response (from student 2679), treating the 5.0 kg box and the 2.0 kg box as a single object:
A sample "r" response (from student 2411), which has the 2.0 kg box accelerating upwards, due to a sign error on a vector direction:
A sample "t" response (from student 1830), with Newton's first law applied to the 2.0 kg box, but Newton's second law correctly applied to the 5.0 kg box. Note that additional step of finding coefficient of kinetic friction:

Physics final exam problem: diagonally downwards-kicked ball

Physics 205A Final Exam, spring semester 2009
Cuesta College, San Luis Obispo, CA

Cf. Giambattista/Richardson/Richardson, Physics, 2/e, Comprehensive Problem 3.96

A ball is kicked off the edge of a cliff at an initial velocity of 15 m/s at angle of 60° below the horizontal. How long does it take for the ball to fall to the ground 40 m below? Neglect air resistance. Show your work and explain your reasoning using properties of projectile motion.

Solution and grading rubric:
  • p:
    Correct. Finds x- and y-components of initial velocity: v0x = +7.50 m/s, v0y = –13.0 m/s; and uses kinematic equations for constant acceleration to solve for t = 1.82 s, implementing the quadratic equation directly, or by first finding the final vertical velocity vy, and then solving for t.
  • r:
    Nearly correct, but includes minor math errors. May also have drawn the initial velocity vector as being 30° below the horizontal.
  • t:
    Nearly correct, but approach has conceptual errors, and/or major/compounded math errors.
  • v:
    Implementation of right ideas, but in an inconsistent, incomplete, or unorganized manner. Some systematic attempt at resolving vectors into components, or using kinematics.
  • x:
    Implementation of ideas, but credit given for effort rather than merit.
  • y:
    Irrelevant discussion/effectively blank.
  • z:
    Blank.

Grading distribution:
Sections 30880, 30881
p: 13 students
r: 9 students
t: 8 students
v: 7 students
x: 2 students
y: 0 students
z: 0 students

A sample "p" response (from student 0506):
Another sample "p" response (from student 1697):
A sample "r" response (from student 3693), with a sign error for the magnitude of vertical acceleration:

20090611

Physics final exam question: icy lake versus hot teapot

Physics 205A Final Exam, Spring Semester 2009
Cuesta College, San Luis Obispo, CA

Cf. Giambattista/Richardson/Richardson, Physics, 2/e, Conceptual Question 14.20

[10 points.] Which possesses more total internal energy, the water within a large, partially ice-covered lake in winter, or a 6-cup teapot filled with hot tea? Explain using the properties of heat and internal energy?

Solution and grading rubric:
  • p = 10/10:
    Correct. At absolute zero (0 kelvins), there is zero total internal energy. It will take much more heat to bring a frozen lake from absolute zero to partially frozen 273 K, than it would to bring a teapot of ice from absolute zero to near/at 373 K, as mass predominates over the delta(T) factors.
  • 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.
  • t = 6/10:
    Nearly correct, but argument has conceptual errors, or is incomplete. Recognizes mass and delta(T) factors are relevant, but chooses delta(T) as the determinant factor.
  • v = 4/10:
    Limited relevant discussion of supporting evidence of at least some merit, but in an inconsistent or unclear manner.
  • 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:
Sections 30880, 30881
p: 12 students
r: 12 students
t: 11 students
v: 3 students
x: 0 students
y: 0 students
z: 1 student

A sample of a "p" response (from student 0402):

Another sample of a "p" response (from student 1830), also taking into consideration the heat put in starting from absolute zero as the amount of internal energy present:

Another sample of a "p" response (from student 1985), using a heat exchange argument between these two systems:

20090610

Physics final exam question: kelvins versus Celsius degrees

Physics 205A Final Exam, Spring Semester 2009
Cuesta College, San Luis Obispo, CA

Cf. Giambattista/Richardson/Richardson, Physics, 2/e, Conceptual Question 13.3

[10 points.] Are there any special circumstances that kelvins or Celsius degrees can be used interchangeably? Explain your answer using the properties of heat and temperature.

Solution and grading rubric:
  • p = 10/10:
    Correct. Kelvins or Celsius degrees can be used interchangeably if changes in temperatures (delta(T)) are involved, typically in calculating the thermal expansion of materials, or the heat transferred to/from thermal energy systems. Discusses/demonstrates the distinction between temperature and temperature differences.
  • 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.
  • t = 6/10:
    Nearly correct, but argument has conceptual errors, or is incomplete. Understands the distinction between kelvins and Celsius degrees only.
  • v = 4/10:
    Limited relevant discussion of supporting evidence of at least some merit, but in an inconsistent or unclear manner.
  • 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:
Sections 30880, 30881
p: 32 students
r: 0 students
t: 6 students
v: 0 students
x: 1 student
y: 0 students
z: 0 students

A sample of a "p" response (from student 1991):

Another sample of a "p" response (from student 0402):

Another sample of a "p" response (from student 1141):

A sample of a "t" response (from student 2484):

20090609

Kudos: not ass kissing

"Not ass-kissing" by Student 1192
Astronomy 210
May 2009
Cuesta College, San Luis Obispo, CA

This a follow-up to answering a final exam question on Pluto not being a planet.

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:
  • 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.
Grading distribution:
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: