Astronomy 10 Quiz 12, Fall Semester 2007
Cuesta College, San Luis Obispo, CA
Astronomy 10 learning goal Q12.3
[3.0 points.] Which one of the following choices best describes the evidence for the existence of dark energy?
(A) Stars in the inner and outer parts of the disk orbit the center of the Milky Way with the same speed.
(B) Each and every galaxy sees all other galaxies moving away from its location.
(C) Nearly equal amounts of cosmic background radiation are detected from all directions.
(D) Distant galaxies appear to be much younger than nearby galaxies.
(E) Type Ia supernovae in distant galaxies appear to be dimmer than expected from their redshifts.
Correct answer: (E)
Since type Ia supernovae in distant galaxies appear to be dimmer than expected from their redshifts, this shifts the slope of the Hubble plot for the long-ago (distant) universe, compared to the recent (nearby) universe. Thus the expansion rate of the universe has been accelerating recently, and this is the evidence for dark energy.
Response (A) describes the evidence for dark matter in the halo of the Milky Way. Response (B) is the consequence of an expanding universe. Response (C) describes the "horizon problem" of the cosmic microwave background, and is the evidence for the inflation era of expansion. Response (D) is the consequence of the finite speed of light.
Student responses
Section 0135
(A) : 4 students
(B) : 3 students
(C) : 13 students
(D) : 2 students
(E) : 7 students
20071224
Erasing slate: cool tablet
"Cool Tablet :)" 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.
20071221
Astronomy quiz question: dark energy destiny
Astronomy 10 Quiz 12, Fall Semester 2007
Cuesta College, San Luis Obispo, CA
Astronomy 10 learning goal Q12.3
[3.0 points.] Which one of the following choices best describes what dark energy may eventually do to the universe in the distant future?
(A) The expansion of space will continue forever, until matter fades away, or is torn apart.
(B) The expansion of space will eventually slow down and stop, and begin contracting as galaxies and stars collide in a "Big Crunch."
(C) Eventually produce enough antimatter to annihilate all matter in the universe.
(D) Stabilize the expansion caused by inflation, such that universe will remain the same size.
(E) Stabilize the contraction caused by dark matter, such that the universe will remain the same size.
Correct answer: (A)
Dark energy is responsible for the recent accelerating expansion of space in the universe. As dark energy is apparently created by space itself, the expansion of space creates more dark energy, which would in turn accelerate the expansion of space, etc. Thus the expansion would steadily increase such that universe would be subject to a "Big Rip" or "Big Tear," as distant galaxies and nearer galaxies recede faster than the speed of light, disappearing from our view, and then locally the expansion of space would rip apart matter itself, overcoming attractive gravitational, electromagnetic, and then nuclear forces.
The "Big Crunch" response (B) had previously been the prevailing prediction for the fate of the universe, before the discovery of accelerating expansion caused by dark energy. For a closed, matter-dominated universe, gravitational forces could eventually overcoming the expansion of space, resulting in slowing down, stopping, and possibly reversing the expansion of space.
Student responses
Section 1073
(A) : 16 students
(B) : 20 students
(C) : 2 students
(D) : 5 students
(E) : 2 students
Cuesta College, San Luis Obispo, CA
Astronomy 10 learning goal Q12.3
[3.0 points.] Which one of the following choices best describes what dark energy may eventually do to the universe in the distant future?
(A) The expansion of space will continue forever, until matter fades away, or is torn apart.
(B) The expansion of space will eventually slow down and stop, and begin contracting as galaxies and stars collide in a "Big Crunch."
(C) Eventually produce enough antimatter to annihilate all matter in the universe.
(D) Stabilize the expansion caused by inflation, such that universe will remain the same size.
(E) Stabilize the contraction caused by dark matter, such that the universe will remain the same size.
Correct answer: (A)
Dark energy is responsible for the recent accelerating expansion of space in the universe. As dark energy is apparently created by space itself, the expansion of space creates more dark energy, which would in turn accelerate the expansion of space, etc. Thus the expansion would steadily increase such that universe would be subject to a "Big Rip" or "Big Tear," as distant galaxies and nearer galaxies recede faster than the speed of light, disappearing from our view, and then locally the expansion of space would rip apart matter itself, overcoming attractive gravitational, electromagnetic, and then nuclear forces.
The "Big Crunch" response (B) had previously been the prevailing prediction for the fate of the universe, before the discovery of accelerating expansion caused by dark energy. For a closed, matter-dominated universe, gravitational forces could eventually overcoming the expansion of space, resulting in slowing down, stopping, and possibly reversing the expansion of space.
Student responses
Section 1073
(A) : 16 students
(B) : 20 students
(C) : 2 students
(D) : 5 students
(E) : 2 students
20071217
Physics clicker question: heat capacity during phase change
Physics 5A, Fall Semester 2007
Cuesta College, San Luis Obispo, CA
Cf. Giambattista/Richardson/Richardson, Physics, 1/e, Conceptual Question 13.11
Students were asked the following clicker question (Classroom Performance System, einstruction.com) at the beginning of their learning cycle:
[0.6 participation points.] The heat capacity of a material undergoing a phase change (such as melting/freezing, or boiling/condensing) is typically:
(A) zero.
(B) infinity.
(C) a finite number.
(D) (Not enough information is given.)
(E) (I'm lost, and don't know how to answer this.)
Sections 0906, 0907
(A) : 10 students
(B) : 12 students
(C) : 11 students
(D) : 0 students
(E) : 0 students
Correct answer: (B)
The heat capacity is defined as the ratio of the heat Q (put in) to the resulting temperature increase delta(T):
C = Q/delta(T).
But when heat is put into, or extracted from a system, its temperature remains constant, making delta(T) = 0, and thus its heat capacity will be undefined as it would approach infinity.
Cuesta College, San Luis Obispo, CA
Cf. Giambattista/Richardson/Richardson, Physics, 1/e, Conceptual Question 13.11
Students were asked the following clicker question (Classroom Performance System, einstruction.com) at the beginning of their learning cycle:
[0.6 participation points.] The heat capacity of a material undergoing a phase change (such as melting/freezing, or boiling/condensing) is typically:
(A) zero.
(B) infinity.
(C) a finite number.
(D) (Not enough information is given.)
(E) (I'm lost, and don't know how to answer this.)
Sections 0906, 0907
(A) : 10 students
(B) : 12 students
(C) : 11 students
(D) : 0 students
(E) : 0 students
Correct answer: (B)
The heat capacity is defined as the ratio of the heat Q (put in) to the resulting temperature increase delta(T):
C = Q/delta(T).
But when heat is put into, or extracted from a system, its temperature remains constant, making delta(T) = 0, and thus its heat capacity will be undefined as it would approach infinity.
20071214
Hot coffee
"Any Tool (That's Some Powerful Hot Coffee!)," by MissChiefWorth1000.com
More Power 7 contest
"Caution: the coffee you are about to drink may be very hot."
20071213
Physics clicker question, movie: Space Shuttle tile
Physics 5A, Fall Semester 2007
Cuesta College, San Luis Obispo, CA
Cf. Giambattista/Richardson/Richardson, Physics, 1/e, Conceptual Question 13.9 (extended)
Students were asked the following clicker question (Classroom Performance System, einstruction.com) at the beginning of their learning cycle:
[0.6 participation points.] A 50 g Space Shuttle heat tile, and a 50 g iron sample each absorb an equal amount of heat from a bunsen burner. Which sample will have a greater increase in temperature?
(A) Space Shuttle tile.
(B) 50 g iron sample.
(C) (Both samples will have approximately the same increase in temperature.)
(D) (I'm lost, and don't know how to answer this.)
Sections 0906, 0907
(A) : 0 students
(B) : 26 students
(C) : 3 students
(D) : 0 students
Correct answer: (B)
The heat capacity is defined as the ratio of the heat Q (put in) to the resulting temperature increase delta(T):
C = Q/delta(T).
The Space Shuttle TPS (thermal protection tile) has a larger heat capacity, as it experiences a small increase in temperature for a given amount of heat, while the iron sample has a smaller heat capacity, experiencing a large increase in temperature with the same amount of heat.
Space Shuttle Thermal Protection System (TPS) Tile
Posted by ntschke
http://www.youtube.com/watch?v=XuSlkEob-3w
Do not touch the tile immediately after heating!
Cuesta College, San Luis Obispo, CA
Cf. Giambattista/Richardson/Richardson, Physics, 1/e, Conceptual Question 13.9 (extended)
Students were asked the following clicker question (Classroom Performance System, einstruction.com) at the beginning of their learning cycle:
[0.6 participation points.] A 50 g Space Shuttle heat tile, and a 50 g iron sample each absorb an equal amount of heat from a bunsen burner. Which sample will have a greater increase in temperature?
(A) Space Shuttle tile.
(B) 50 g iron sample.
(C) (Both samples will have approximately the same increase in temperature.)
(D) (I'm lost, and don't know how to answer this.)
Sections 0906, 0907
(A) : 0 students
(B) : 26 students
(C) : 3 students
(D) : 0 students
Correct answer: (B)
The heat capacity is defined as the ratio of the heat Q (put in) to the resulting temperature increase delta(T):
C = Q/delta(T).
The Space Shuttle TPS (thermal protection tile) has a larger heat capacity, as it experiences a small increase in temperature for a given amount of heat, while the iron sample has a smaller heat capacity, experiencing a large increase in temperature with the same amount of heat.
Space Shuttle Thermal Protection System (TPS) Tile
Posted by ntschke
http://www.youtube.com/watch?v=XuSlkEob-3w
Do not touch the tile immediately after heating!
20071212
Physics clicker question: molecular rms speeds
Physics 5A, Fall Semester 2007
Cuesta College, San Luis Obispo, CA
Cf. Giambattista/Richardson/Richardson, Physics, 1/e, Conceptual Question 13.1 (extended)
Students were asked the following clicker question (Classroom Performance System, einstruction.com) at the beginning of their learning cycle:
[0.6 participation points.] Which type of air molecule has the fastest rms speed at room temperature?
(A) CO2.
(B) H2O.
(C) N2.
(D) O2.
(E) (I'm lost, and don't know how to answer this.)
Sections 0906, 0907
(A) : 5 students
(B) : 9 students
(C) : 14 students
(D) : 4 students
(E) : 0 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, in order to see if students were going to be able to discuss and determine the correct answer among themselves.
Sections 0906, 0907
(A) : 5 students
(B) : 14 students
(C) : 9 students
(D) : 2 students
(E) : 0 students
Correct answer: (B)
The rms speed of a particle is given by:
v_rms = sqrt(3*k*T/m),
where k is Boltzmann's constant, T is the absolute temperature (in Kelvin), and m is the particle mass (in kg). In unified atomic mass units, the masses of these molecules are 44 u, 18 u, 28 u, and 32 u, respectively, making H2O (the lightest molecular mass in this list) the molecule with the fastest rms speed.
Cuesta College, San Luis Obispo, CA
Cf. Giambattista/Richardson/Richardson, Physics, 1/e, Conceptual Question 13.1 (extended)
Students were asked the following clicker question (Classroom Performance System, einstruction.com) at the beginning of their learning cycle:
[0.6 participation points.] Which type of air molecule has the fastest rms speed at room temperature?
(A) CO2.
(B) H2O.
(C) N2.
(D) O2.
(E) (I'm lost, and don't know how to answer this.)
Sections 0906, 0907
(A) : 5 students
(B) : 9 students
(C) : 14 students
(D) : 4 students
(E) : 0 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, in order to see if students were going to be able to discuss and determine the correct answer among themselves.
Sections 0906, 0907
(A) : 5 students
(B) : 14 students
(C) : 9 students
(D) : 2 students
(E) : 0 students
Correct answer: (B)
The rms speed of a particle is given by:
v_rms = sqrt(3*k*T/m),
where k is Boltzmann's constant, T is the absolute temperature (in Kelvin), and m is the particle mass (in kg). In unified atomic mass units, the masses of these molecules are 44 u, 18 u, 28 u, and 32 u, respectively, making H2O (the lightest molecular mass in this list) the molecule with the fastest rms speed.
20071211
Physics clicker question: molar mass
Physics 5A, Fall Semester 2007
Cuesta College, San Luis Obispo, CA
Cf. Giambattista/Richardson/Richardson, Physics, 1/e, Conceptual Question 13.11
Students were asked the following clicker question (Classroom Performance System, einstruction.com) at the beginning of their learning cycle:
[0.6 participation points.] The mass of a single aluminum atom is 27.0 u. What is the mass of one mole of aluminum atoms?
(A) (27.0/N_A) g = 4.48*10^-23 g.
(B) 27.0 g.
(C) 27.0 kg.
(D) (N_A/27.0) g = 2.23*10^22 g.
(E) (27.0*N_A) g = 1.63*10^25 g.
(F) (I'm lost, and don't know how to answer this.)
Sections 0906, 0907
(A) : 11 students
(B) : 5 students
(C) : 2 students
(D) : 4 students
(E) : 9 students
(F) : 2 students
Correct answer: (B)
The unified atomic mass unit, "u" is defined to be exactly 1/12th the mass of one mole of carbon-12 atoms (as opposed to the defunct "amu" atomic mass unit, which is either defined to be exactly 1/16th the mass of one mole of oxygen-16 atoms, or 1/16th the mass of one mole of all isotopes of oxygen as found in their naturally occurring proportions). Thus the mass of any particle, in unified atomic mass units, is exactly the mass of one mole of these particles.
Cuesta College, San Luis Obispo, CA
Cf. Giambattista/Richardson/Richardson, Physics, 1/e, Conceptual Question 13.11
Students were asked the following clicker question (Classroom Performance System, einstruction.com) at the beginning of their learning cycle:
[0.6 participation points.] The mass of a single aluminum atom is 27.0 u. What is the mass of one mole of aluminum atoms?
(A) (27.0/N_A) g = 4.48*10^-23 g.
(B) 27.0 g.
(C) 27.0 kg.
(D) (N_A/27.0) g = 2.23*10^22 g.
(E) (27.0*N_A) g = 1.63*10^25 g.
(F) (I'm lost, and don't know how to answer this.)
Sections 0906, 0907
(A) : 11 students
(B) : 5 students
(C) : 2 students
(D) : 4 students
(E) : 9 students
(F) : 2 students
Correct answer: (B)
The unified atomic mass unit, "u" is defined to be exactly 1/12th the mass of one mole of carbon-12 atoms (as opposed to the defunct "amu" atomic mass unit, which is either defined to be exactly 1/16th the mass of one mole of oxygen-16 atoms, or 1/16th the mass of one mole of all isotopes of oxygen as found in their naturally occurring proportions). Thus the mass of any particle, in unified atomic mass units, is exactly the mass of one mole of these particles.
20071210
Physics clicker question: opening in heated metal plate
Physics 5A, Fall Semester 2007
Cuesta College, San Luis Obispo, CA
Cf. Giambattista/Richardson/Richardson, Physics, 1/e, Conceptual Question 13.4 (extended)
Students were asked the following clicker question (Classroom Performance System, einstruction.com) at the beginning of their learning cycle:
[0.6 participation points.] A square opening is made in a metal plate. If the metal plate is heated up from room temperature by 100 degrees C, what happens to the size of the square opening?
(A) The square opening becomes smaller.
(B) The square opening becomes larger.
(C) The square opening remains the same size as before.
(D) (Not enough information is given.)
(E) (I'm lost, and don't know how to answer this.)
Sections 0906, 0907
(A) : 19 students
(B) : 12 students
(C) : 2 students
(D) : 0 students
(E) : 0 students
Correct answer: (B)
All dimensions, external as well as internal in the metal plate expand when it is heated, and this includes the dimensions of the square opening. However, the hole in the middle of a ring of donut batter will get smaller as the donut cooks in oil, but this is an entirely different phenonomenon--no "fluffy donuts!"
Cuesta College, San Luis Obispo, CA
Cf. Giambattista/Richardson/Richardson, Physics, 1/e, Conceptual Question 13.4 (extended)
Students were asked the following clicker question (Classroom Performance System, einstruction.com) at the beginning of their learning cycle:
[0.6 participation points.] A square opening is made in a metal plate. If the metal plate is heated up from room temperature by 100 degrees C, what happens to the size of the square opening?
(A) The square opening becomes smaller.
(B) The square opening becomes larger.
(C) The square opening remains the same size as before.
(D) (Not enough information is given.)
(E) (I'm lost, and don't know how to answer this.)
Sections 0906, 0907
(A) : 19 students
(B) : 12 students
(C) : 2 students
(D) : 0 students
(E) : 0 students
Correct answer: (B)
All dimensions, external as well as internal in the metal plate expand when it is heated, and this includes the dimensions of the square opening. However, the hole in the middle of a ring of donut batter will get smaller as the donut cooks in oil, but this is an entirely different phenonomenon--no "fluffy donuts!"
20071207
Astronomy quiz question: lavender/pink and blue nebulae
Astronomy 10 Quiz 11, Fall Semester 2007
Cuesta College, San Luis Obispo, CA
Astronomy 10 learning goal Q11.1
[Version 1]
[3.0 points.] Which one of the following choices best describes what causes the color of a lavender/pink nebula?
(A) Photons emitted by electrons.
(B) Scattered light from stars.
(C) Blackbody radiation.
(D) Gravitational contraction.
(E) Dark matter.
Correct answer: (A)
The lavender/pink color is the mixture of several visible light photons of different wavelengths, emitted when an electron jumps down several hydrogen orbitals.
Student responses
Section 0135
(A) : 17 students
(B) : 9 students
(C) : 3 students
(D) : 2 students
(E) : 1 student
[Version 2]
[3.0 points.] Which one of the following choices best describes what causes the color of a blue nebula?
(A) Photons emitted by electrons.
(B) Scattered light from stars.
(C) Blackbody radiation.
(D) Gravitational contraction.
(E) Dark matter.
Correct answer: (B)
Very small dust particles will scatter short wavelengths of light more than long wavelengths. Thus red light will typically pass through this type of nebula, while blue light will be scattered in all directions.
Student responses
Section 1073
(A) : 12 students
(B) : 27 students
(C) : 1 student
(D) : 0 students
(E) : 2 students
Cuesta College, San Luis Obispo, CA
Astronomy 10 learning goal Q11.1
[Version 1]
[3.0 points.] Which one of the following choices best describes what causes the color of a lavender/pink nebula?
(A) Photons emitted by electrons.
(B) Scattered light from stars.
(C) Blackbody radiation.
(D) Gravitational contraction.
(E) Dark matter.
Correct answer: (A)
The lavender/pink color is the mixture of several visible light photons of different wavelengths, emitted when an electron jumps down several hydrogen orbitals.
Student responses
Section 0135
(A) : 17 students
(B) : 9 students
(C) : 3 students
(D) : 2 students
(E) : 1 student
[Version 2]
[3.0 points.] Which one of the following choices best describes what causes the color of a blue nebula?
(A) Photons emitted by electrons.
(B) Scattered light from stars.
(C) Blackbody radiation.
(D) Gravitational contraction.
(E) Dark matter.
Correct answer: (B)
Very small dust particles will scatter short wavelengths of light more than long wavelengths. Thus red light will typically pass through this type of nebula, while blue light will be scattered in all directions.
Student responses
Section 1073
(A) : 12 students
(B) : 27 students
(C) : 1 student
(D) : 0 students
(E) : 2 students
20071206
Erasing slate: have a nice day
"[flower] Have a nice day!" 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.
20071205
Student scribble: sleepy time
"Sleepy Time" by AnonymousFall Semester 2007
Cuesta College, San Luis Obispo, CA
Found artifact from student notebook.
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