September 2, 2007
The key chart graphically relating instaneous, average, and difference kinematic variables.
20070831
The physics chain of pain
September 2, 2007
The key chart graphically relating instaneous, average, and difference kinematic variables.
20070830
The dudes of displacement
Delta Chi fraternity membersFrostburg State University
Frostburg, MD
http://involvement.frostburg.edu/pic_gallery/Delta_chi.jpg
Displacement vector lovers, represent!
20070829
Total lunar eclipse: August 28, 2007
070828lunareclipse.jpgOriginally uploaded by Waifer X
Total lunar eclipse sequence, photographed through Cuesta College's Dobsonian-mounted 8" reflector using a point-and-shoot 4-megapixel digital camera (Pentax Optio S40).
20070828
Physics clicker question: what is not a vector?
Physics 5A, Fall Semester 2007
Cuesta College, San Luis Obispo, CA
Cf. Giambattista/Richardson/Richardson, Physics, 1/e, Chapter 2.2
Students were asked the following clicker question (Classroom Performance System, einstruction.com) near the beginning of their learning cycle:
[0.3 participation points.] Consider the following list of quantities:
Position.
Displacement.
Distance traveled by an object.
How many of the above quantities are vectors? _____.
Correct answer: 2.
Student responses
Sections 0906, 0907
"1" : 16 students
"2" : 28 students
"3" : 2 students
Teachable moment! Students were then asked to identify the one quantity that was not a vector, eliciting various responses, most notably "position." Following discussion ensues:
Cuesta College, San Luis Obispo, CA
Cf. Giambattista/Richardson/Richardson, Physics, 1/e, Chapter 2.2
Students were asked the following clicker question (Classroom Performance System, einstruction.com) near the beginning of their learning cycle:
[0.3 participation points.] Consider the following list of quantities:
Position.
Displacement.
Distance traveled by an object.
How many of the above quantities are vectors? _____.
Correct answer: 2.
Student responses
Sections 0906, 0907
"1" : 16 students
"2" : 28 students
"3" : 2 students
Teachable moment! Students were then asked to identify the one quantity that was not a vector, eliciting various responses, most notably "position." Following discussion ensues:
- "Displacement" is a vector, pointing from the initial to the final location.
- "Distance traveled by an object" is not a vector but a scalar, and in one-dimensional travel may move back and forth along itself.
- "Position" is a vector, as it points from the origin to the location. Many students were thinking of a location as just a point, and thus not a vector. Or a few students had considered a special case that if an object starts from the origin, then its initial position is then a point and not a vector; but this brings up the special case of a null vector.
20070827
Erasing slate: shocked and awed?
"Untitled" by AnonymousFall Semester 2007
Cuesta College, San Luis Obispo, CA
Latest scribbling on the lift-and-erase slate in the hallway, outside the office door.
20070824
Physic clicker question: one billion dinara note
Physics 5A, Fall Semester 2007
Cuesta College, San Luis Obispo, CA
Cf. Giambattista/Richardson/Richardson, Physics, 1/e, Chapter 1.4
Inflacija, by Goranka Matic
As posted on boingboing.net
May 4, 2006
Students were asked the following clicker question (Classroom Performance System, einstruction.com) near the beginning of their learning cycle:
[0.3 points.] Consider an old Yugoslavian billion dinara banknote.
Enter the number of significant figures: _____.
When a number is written in non-scientific notation with empty zeros, the number of significant figures is ambiguous. The rule of thumb here is to follow the "min 2" rule, where this would be expressed in scientific notation as 1.0 x 10^9 dinara. However, assuming that dinara can be exchanged into 100 cents (the practicalities of inflation notwithstanding), then currency would be significant to the hundredths decimal place, so this would be 1.00000000000 x 10^9 dinara.
The point is that there are different rules in science and in finance, so unless it is clear that money is being discussed, the "min 2" rule will apply to ambiguous zeros.
Correct answer: 2, or 12.
Student responses
Sections 0906, 0907
"1" : 3 students
"2" : 23 students
"10": 1 student
Cuesta College, San Luis Obispo, CA
Cf. Giambattista/Richardson/Richardson, Physics, 1/e, Chapter 1.4
Inflacija, by Goranka MaticAs posted on boingboing.net
May 4, 2006
Students were asked the following clicker question (Classroom Performance System, einstruction.com) near the beginning of their learning cycle:
[0.3 points.] Consider an old Yugoslavian billion dinara banknote.
Enter the number of significant figures: _____.
When a number is written in non-scientific notation with empty zeros, the number of significant figures is ambiguous. The rule of thumb here is to follow the "min 2" rule, where this would be expressed in scientific notation as 1.0 x 10^9 dinara. However, assuming that dinara can be exchanged into 100 cents (the practicalities of inflation notwithstanding), then currency would be significant to the hundredths decimal place, so this would be 1.00000000000 x 10^9 dinara.
The point is that there are different rules in science and in finance, so unless it is clear that money is being discussed, the "min 2" rule will apply to ambiguous zeros.
Correct answer: 2, or 12.
Student responses
Sections 0906, 0907
"1" : 3 students
"2" : 23 students
"10": 1 student
20070823
Physics clicker question: significant figures
Physics 5A, Fall Semester 2007
Cuesta College, San Luis Obispo, CA
Cf. Giambattista/Richardson/Richardson, Physics, 1/e, Chapter 1.4
Students were asked the following clicker question (Classroom Performance System, einstruction.com) near the beginning of their learning cycle:
[0.3 points.] Consider these five length measurements:
(A) 0.00409 m.
(B) 81.602 m.
(C) 1.970 × 10^3 cm.
(D) 80,000 km.
(E) 80,000.0 mm.
Which measurement has the most number of significant figures?
Student responses
Sections 0906, 0907
(A) : 5 students
(B) : 6 students
(C) : 3 students
(D) : 3 students
(E) : 10 students
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, as students were able to discuss and determine the correct answer among themselves.
[0.3 points.] Consider these five length measurements:
(A) 0.00409 m.
(B) 81.602 m.
(C) 1.970 × 10^3 cm.
(D) 80,000 km.
(E) 80,000.0 mm.
Which measurement has the most number of significant figures?
Correct answer: (E)
Student responses
Sections 0906, 0907
(A) : 2 students
(B) : 0 students
(C) : 1 student
(D) : 0 students
(E) : 24 students
Cuesta College, San Luis Obispo, CA
Cf. Giambattista/Richardson/Richardson, Physics, 1/e, Chapter 1.4
Students were asked the following clicker question (Classroom Performance System, einstruction.com) near the beginning of their learning cycle:
[0.3 points.] Consider these five length measurements:
(A) 0.00409 m.
(B) 81.602 m.
(C) 1.970 × 10^3 cm.
(D) 80,000 km.
(E) 80,000.0 mm.
Which measurement has the most number of significant figures?
Student responses
Sections 0906, 0907
(A) : 5 students
(B) : 6 students
(C) : 3 students
(D) : 3 students
(E) : 10 students
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, as students were able to discuss and determine the correct answer among themselves.
[0.3 points.] Consider these five length measurements:
(A) 0.00409 m.
(B) 81.602 m.
(C) 1.970 × 10^3 cm.
(D) 80,000 km.
(E) 80,000.0 mm.
Which measurement has the most number of significant figures?
Correct answer: (E)
Student responses
Sections 0906, 0907
(A) : 2 students
(B) : 0 students
(C) : 1 student
(D) : 0 students
(E) : 24 students
20070822
Physics clicker question: significance of signficant figures
Physics 5A, Fall Semester 2007
Cuesta College, San Luis Obispo, CA
Cf. Giambattista/Richardson/Richardson, Physics, 1/e, Chapter 1.4
Invisible Measuring Tape, by rm
icanhascheezburger.com
March 27, 2007
Students were asked the following clicker question (Classroom Performance System, einstruction.com) near the beginning of their learning cycle:
[0.3 points.] The number of significant figures measures:
(A) accuracy.
(B) precision.
(C) determinacy.
(D) significancy.
For many students "accuracy" and "precision" are synonymous, but there is an important distinction between them!
Correct answer: (B).
Student responses
Sections 0906, 0907
(A) : 11 students
(B) : 15 students
(C) : 0 students
(D) : 2 students
N.B. This was the very first clicker question of the semester!
Cuesta College, San Luis Obispo, CA
Cf. Giambattista/Richardson/Richardson, Physics, 1/e, Chapter 1.4
Invisible Measuring Tape, by rmicanhascheezburger.com
March 27, 2007
Students were asked the following clicker question (Classroom Performance System, einstruction.com) near the beginning of their learning cycle:
[0.3 points.] The number of significant figures measures:
(A) accuracy.
(B) precision.
(C) determinacy.
(D) significancy.
For many students "accuracy" and "precision" are synonymous, but there is an important distinction between them!
Correct answer: (B).
Student responses
Sections 0906, 0907
(A) : 11 students
(B) : 15 students
(C) : 0 students
(D) : 2 students
N.B. This was the very first clicker question of the semester!
20070821
Astronomy current events questions: August 28, 2007 event, and Mars e-mail hoax
Astronomy 10L, Fall Semester 2007
Cuesta College, San Luis Obispo, CA
Students are assigned to read online articles on current astronomy events (skytonight.com, from Sky & Telescope magazine), 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!)
A sample quiz is given to the students on the first lab meeting of the semester, and is not graded.
[0.2 points.] What special astronomical event will occur from 2:52 AM to 4:22 AM on August 28, 2007 for observers in San Luis Obispo, CA?
(A) A total lunar eclipse.
(B) A total solar eclipse.
(C) A discarded service module from the International Space Station will burn up as it enters the atmosphere.
(D) Daylight savings time will end.
(E) The Perseid meteor shower will reach its peak.
Correct answer: (A).
[0.2 points.] What recent e-mail hoax is circulating on the internet regarding Mars?
(A) Mars will appear as large as the full Moon, to the naked eye sometime this month.
(B) Mars is completely covered by a dust storm that shrouds the entire planet.
(C) A NASA space probe launched this month will land on Mars only nine months from now.
(D) The NASA already lost radio contact with the Mars rovers Spirit and Opportunity over one year ago.
(E) The temperature of Mars proves that global warming is actually caused by sunspot activity.
Correct answer: (A).
Cuesta College, San Luis Obispo, CA
Students are assigned to read online articles on current astronomy events (skytonight.com, from Sky & Telescope magazine), 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!)
A sample quiz is given to the students on the first lab meeting of the semester, and is not graded.
[0.2 points.] What special astronomical event will occur from 2:52 AM to 4:22 AM on August 28, 2007 for observers in San Luis Obispo, CA?
(A) A total lunar eclipse.
(B) A total solar eclipse.
(C) A discarded service module from the International Space Station will burn up as it enters the atmosphere.
(D) Daylight savings time will end.
(E) The Perseid meteor shower will reach its peak.
Correct answer: (A).
[0.2 points.] What recent e-mail hoax is circulating on the internet regarding Mars?
(A) Mars will appear as large as the full Moon, to the naked eye sometime this month.
(B) Mars is completely covered by a dust storm that shrouds the entire planet.
(C) A NASA space probe launched this month will land on Mars only nine months from now.
(D) The NASA already lost radio contact with the Mars rovers Spirit and Opportunity over one year ago.
(E) The temperature of Mars proves that global warming is actually caused by sunspot activity.
Correct answer: (A).
20070820
Neverending cycle
"For Dan In Taiwan" by Jessica Hagyindexed.blogspot.com, July 30, 2007
And so it begins, the start of another academic year at Cuesta College!
20070817
Scale movie: planets and stars
"Planets and Stars," posted by nectarianhttp://www.youtube.com/watch?v=_WEL117xXpw
By no means the first such scale movie (and no, Pluto is no longer a planet!), but done nicely without having previous objects pull back into perspective behind foreground objects, which would distort the scale comparison.
20070816
Crying over spilt...Milky Way
"Milky" Way, by claramaraWorth1000.com
Alternate Explanations 3 contest
Several Greek myths discuss the origins of the Milky Way ("Galaxias," from "gala" or milk) as seen from Earth, with Hera unknowingly breastfeeding Heracles, or Rhea attempting to breastfeed a stone in swaddling clothes to dupe her husband Cronus.
Further discussion: Milky Way (mythology), from wikipedia.org.
20070815
Meteor shower movie
Leonids meteor storm (*.mov, 66 MB)http://metaresearch.org/expeditions/past/storms/Leonids-fullscrn-download.wmv
From MetaResearch.org, an apparently pseudoscientific (but interesting) website:
H. John Wood acquired an excellent 2-hour video of the 19 November 2002 Leonids storm. The image tube was pointed toward the radiant, making most of the trails very short. Matthew Willson has extracted a 6-minute portion near the storm peak so that our web site visitors can get a sense of what this rare spectacle was like. The video is sped up by approximately a factor of three from real time. However, the field of view covers only about 10% of the sky. So the video extract shows only about 1/3 of the real-time meteor rates that an on-site observer might have seen under ideal viewing conditions.
20070814
The showerhead effect
Janet Leigh in Psycho(Paramount/Universal Pictures, 1960)
The meteor tracks for the Perseid meteor shower appear to diverge from the constellation Perseus (which is the epynomous "radiant" for that meteor shower). Although these meteor tracks are essentially parallel, they appear to radiate outwards from that point in the sky due to "The Showerhead Effect."
20070810
Kudos: awesome new world of astronomy
"Awesome New World of Astronomy" by Genesis N.Astronomy 10
July 2007
Cuesta College, San Luis Obispo, CA
20070809
Heat death of the universe
Dinosaur Comics, by Ryan Northwww.qwantz.com
July 18, 2007 (excerpt)
Astronomy 10 learning goal Q12.3
Ryan North hits another one out of the park, astronomy-wise, in describing the heat death that will result from the expansion of the universe (exacerbated by the acceleration due to dark energy?), imagined here as a "Choose Your Adventure." But at least there is a happy ending in the last panel.
Previous post: comment on Ryan North's Dinosaur Comics discussion of the tidal slowing of Earth's rotation.
20070802
Crop circle signs of intelligence
Driver comes a cropper in police chase, metro.co.uk
June 25, 2007
Physics 8A learning goal F.3
A driver allegedly under the influence of cocaine, pursued by four police cars in a corn field in the Netherlands. Would this pattern be interpreted as a purposeful sign of intelligence by extraterrestrials?
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