Astronomy clicker question: retrograde/prograde rise/set

Astronomy 10, Summer Session 2007
Cuesta College, San Luis Obispo, CA

Astronomy 10 learning goal Q3.2

Students were asked the following clicker question (Classroom Performance System, einstruction.com) near the end of their learning cycle:

[0.3 points.] As seen from San Luis Obispo, CA, when a planet is in retrograde motion, how will it move in a single night?
(A) It will rise from the east horizon, and set in the west horizon.
(B) It will rise from the east horizon, and shortly afterwards set in the east horizon.
(C) It will rise from the west horizon, and set in the east horizon.
(D) It will rise from the west horizon, and shortly afterwards set in the west horizon.

Correct answer: (A).

Most students are probably thinking that retrograde motion (planet moves a very small distance east-to-west relative to the background stars) is the reason why it will rise in the east horizon, and set in the west horizon. The next clicker question will test for this misconception.

Student responses
Section 8027
(A) : 11 students
(B) : 1 student
(C) : 2 students
(D) : 0 students

[0.3 points.] As seen from San Luis Obispo, CA, when a planet is in prograde motion, how will it move in a single night?
(A) It will rise from the east horizon, and set in the west horizon.
(B) It will rise from the east horizon, and shortly afterwards set in the east horizon.
(C) It will rise from the west horizon, and set in the east horizon.
(D) It will rise from the west horizon, and shortly afterwards set in the west horizon.

Correct answer: (A).

This follow-up question causes a lot of consternation for students, who must realize that in prograde motion, a planet moves a very small distance west-to-east relative to the background stars, which themselves over a single night rise from the east horizon, and set in the west horizon. Thus a planet will be seen to rise from the east horizon, and set in the west horizon in a single night, regardless if it is undergoing retrograde or prograde motion!

Student responses
Section 8027
(A) : 3 students
(B) : 1 student
(C) : 10 students
(D) : 0 students

Carousel teacup epicycle movie

070526 Carousel Teacup Epicycle
Venetian Carousel, K Street Mall
Sacramento, CA
http://www.youtube.com/watch?v=FIsiezgo7nY

Astronomy 10 learning goal Q3.2

Dramatization of planetary motion in the Ptolemaic model. Watch the girl in the teacup (planet on epicycle) as the merry-go-round (the deferent), well, goes around and around.

General relativity: warped spacetime

"Spacetime 2"
David J. Grossman (c) 1996
http://unpronounceable.com/graphics/raytraces/spactim2.html

What better way to depict the gravitational distortion of spacetime than with distorted Einsteins?

Astronomy clicker question: lunar phases

Astronomy 10, Summer Session 2007
Cuesta College, San Luis Obispo, CA

Astronomy 10 learning goal Q2.1

Students were asked the following clicker question (Classroom Performance System, einstruction.com) at the start of their learning cycle:

[0.3 points.] Shown below are eight different Moon phases.


What causes these different phases of the Moon?
(A) Different amounts of the far and near sides of the Moon as seen from the Earth.
(B) Different amounts of the day and night sides of the Moon as seen from the Earth.
(C) The Earth blocks light from the Sun, casting a shadow on the Moon.
(D) The slow, gradual rotation of the Moon about its own axis.

Correct answer: (B).

The border between the sides of the Moon that are illuminated or non-illuminated by the Sun is the terminator. As the Moon orbits the Earth (in approximately 28 days), the terminator moves across the face of the Moon. Students are instructed to diagram this, in order to construct a mental model of this phenomenon.

Student responses
Section 8027
(A) : 1 student
(B) : 4 students
(C) : 7 students
(D) : 1 student

Universe expansion movie

Continued Consistent Expansion (*.mov, 3.7 MB)
Hubblesite.org

Astronomy 10 learning goal Q12.2

This movie is not just a zoom-in shot! Note that as the universe expands, the distances between galaxies increases, while the size of the galaxies remains constant (due to gravitational interactions). This can be illustrated during the movie by covering one of the galaxies with the mouse cursor, and showing that that the size of the galaxy does not change relative to the cursor.

Geocentrism, redux

"Something's going wrong. Stop the global warming."

Dogal Hayati Koruma Dernegi (Turkish Nature Life Protection Association), www.dhkd.org
(Via shedwa.blogspot.com)

Astronomy 10 learning goal Q3.2

Ignorance of global warming is equated with the antiquated geocentric model of planetary motion.

Pirate displacement vectors

Bizarro, by Dan Piraro
www.bizarro.com
June 18, 2007

Physics 8A learning goal Q1.3

GPS is concerned with position vectors, here we have pirate displacement vectors!

Rifle bugle

Rifle Barrel Becomes Bugle for Musical Stunt
Popular Science, March 1938
blog.modernmechanix.com

Physics 8B learning goal Q1.4

Even though the bolt has been removed, don't try this at home?

Kudos: frequency of the electric wave...

(Front)

(Back)

"Frequency of the Electric Wave..." by Mary W. and Janet L.
Physics 5B
Spring Quarter 1991
University of California, Davis, CA

Bon mot: on the shoulders of giants

Illustration by Matt Collins
www.mattcollins.com

"If I have seen a little further it is by standing on the shoulders of Giants."
--Isaac Newton

Elaboration of this metaphor in contemporary and earlier attributions is discussed on Wikipedia. Apparently it has been adopted as the byword of Google Scholar.

"Ultra Violet" wine

"Ultra Violet" Merlot wine bottle label
Casa de Caballos Vineyards
Paso Robles, CA

Would they happen to have an Infrared Zinfandel?

Kudos: P-A-T

Anonymous
Physics 7B course evaluation
Winter Quarter 2001
University of California, Davis, CA

Kudos: love and amazement of the universe

"Love and Amazement of the Universe" by Carley F.
Astronomy 10
May 2007
Cuesta College, San Luis Obispo, CA

Kudos: jigsaw puzzle

(Front)

(Back)

"Thanks!!!!!" by Charissa S.
Physics 7C
December 1998
University of California, Davis, CA

Overheard: pee-pee

Physics 7B, Fall Quarter 2002
University of California, Davis, CA

Excerpt from a student e-mail regarding placement of the origin (pivot point) for torque calculations:

Anyways I just had a thing [that] helped me in PHYS 7B. "Beware where you place your P.P." P.P. as in pivot point you know, but it's cool cause it sounds like pee-pee. Ha-ha, well anyways, thanks for being a good prof and bearing with my office hour visits.
--K. H.

Schrödinger's lolcat

Schrodinger's lolcat
Originally uploaded by dantekgeek, from original photo by Keven Steele

Physics 8C learning goal QX.x

This one lives... Close the box and try again. Or don't open the box, and keep 'em guessing.