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Clicker Questions for NEXUS/Physics
Fluids
A note on usage:
The clicker slides in this booklet are meant
to be used as stimuli to encourage class discussion.
They are intended for use in a class that attempts
to help students develop a coherent and sophisticated
understanding of scientific thinking.
They are NOT intended as items to test whether
students are “right or wrong” or “know” the correct
answer by one-step recall if enough cues are given.
This has a number of instructional implications
that are reviewed in general on the next four slides.
The individual slides also contain annotations
discussing their intended use.
Usage: 1
• Feedback
One of the most important values of a clickerresponse system is to provide instructors with
some understanding of what students are thinking.
Good clicker questions can be highly revealing
(and surprising). But the critical fact is not that the
students make mistakes but to use those mistakes
to probe their thinking and find out why.
This raises the importance of a rich subsequent
discussion well above “letting the students know
what the right answer is.”
Usage 2:
• Student-student interactions
The critical value for student learning occurs
in what happens after a clicker question has
obtained a mixed response from the students.
The standard next cue is, “Find someone
who disagreed with the answer you chose
and see if you can convince them.”
After a minute or two of discussion, a second click
may show students having moved dramatically
towards the correct answer. A brief call for who
changed their answer and why can lead to a
useful exchange. When they have not moved
significantly, more discussion is called for.
Usage: 3
• Incompletely specified questions
Some items have questions that are simple if idealized
assumptions are made, subtler if they are not. Part of
the discussion of these items are intended to include
issues of modeling, idealizations, and hidden
assumptions.
• Questions where answers are not provided.
In these items, the intent is to have students come up
with potential answers and have the instructor collect
them and write them on the board.
Occasionally, especially at the beginning of a class, it may
take some time before students are willing to contribute
answers. It can help if you have some prepared answers
ready, walk around the class, and put up the answers as if
they came from the students. This can help students get
more comfortable with contributing.
Usage: 4
• Cluster questions
Some questions are meant to be used as part of a
group of questions. In this case, resolving the answers
to individual questions is better left until the entire
group is completed. The value of the questions are
often in the comparison of the different items and in
having students think about what changes lead to what
differences and why.
• Problem solving items
In these items (indicated by a pencil cluster logo), the
intent is to have students work together to solve some
small problem. After a few minutes, ask the groups to
share their answers, vote on the different answers
obtained, and have a discussion.
A cylinder with a movable piston
is filled with a uniform fluid. If the
corks are all in equally tightly,
which are most likely to pop when
we hit the piston with a hammer?
A.
B.
C.
D.
E.
F.
G.
Cork 1
Corks 1 & 2
Cork 3
Cork 4
Some other combination
All
None
1
2
3
4
An object hung from a spring
scale is lowered into water.
When the object is immersed,
the scale will read
A.
B.
C.
D.
a larger value
a smaller value
the same value
can’t tell – not enough info
Consider the containers at right.
Which of the following correctly
compares the pressure (P) of the
water at the bottoms of the containers?
A.
B.
C.
D.
E.
F.
G.
P1 = P2 = P3
P3 > P1 > P2
P3 > P1 = P2
P2 > P1 > P3
P1 = P2 > P3
P2 > P1 = P3
None of these
(1)
(2)
(3)
Consider the containers at right.
Which of the following correctly
compares the force (F) exerted by the
water on the bottoms of the containers?
A.
B.
C.
D.
E.
F.
G.
F1 = F2 = F3
F3 > F1 > F2
F3 > F1 = F2
F2 > F1 > F3
F1 = F2 > F3
F2 > F1 = F3
None of these
(1)
(2)
(3)
Three cubes of equal volume are
hung on strings. A and B have the same
mass and block C has less. The blocks
are lowered into a fish tank and they hang
at rest as shown.
How does the force exerted by the water
on the top surface of cube A compare to
the force exerted by the water
on the top surface of cube B?
A. The force on A is bigger
B. The force on B is bigger
C. They are the same.
Three cubes of equal volume are
hung on strings. A and B have the same
mass and block C has less. The blocks
are lowered into a fish tank and they hang
at rest as shown.
How do the buoyant forces exerted by the water on the
three cubes rank?
A.
B.
C.
D.
E.
BFB > BFA = BFC
BFB = BFA > BFC
BFB > BFA > BFC
BFA = BFB = BFC
Some other ranking
A. greater than
B. less than
C. the same as
10/28/11
13
A chunk of iron is sitting on a table. It is then
moved from the table into a bucket of water
sitting on the table. The iron now rests on the
bottom of the bucket. The force the bucket
exerts on the chunk when the block is sitting on
the bottom of the bucket is __________the
force that the table exerted on the chunk when
the chunk was sitting on the table.
Ph
ysi
cs
13
A. greater than
B. less than
C. the same as
10/28/11
14
A chunk of iron is sitting on a table. It is then
moved from the table into a bucket of water
sitting on the table. The iron now rests on the
bottom of the bucket. The total force on the
chunk when it is sitting on the bottom of the
bucket is __________ it was on the table.
Ph
ysi
cs
13
A. greater than
B. less than
C. the same as
10/28/11
15
A chunk of iron is sitting on a table. It is then
covered by a bell jar which has a nozzle
connected to a vacuum pump. The air is
extracted from the bell jar. The force the table
exerts on the block when the block is sitting in a
vacuum is __________ the force that the table
exerted on the block when the block was sitting
in the air
Ph
ysi
cs
13
A. greater than
B. less than
C. the same as
10/28/11
16
A chunk of iron is sitting on a scale. The iron
and the scale are then both immersed in a large
vat of water. After being immersed in the water,
the scale reading will be __________ the scale
reading when they were simply sitting in the air.
(Assume the scale would read zero if nothing
were sitting on it, even when it is under water.)
Ph
ysi
cs
13
A ball floats in a beaker of water. The ball sinks
in a beaker of mineral spirits. The mineral spirit will float
above the water when poured slowly on top of water.
If the ball is floating on the water
2/3 of the way under the water,
what will happen to the ball when
mineral spirits is slowly poured
on top of the water?
• Relative to the top of the water,
A. The ball will go down.
B. The ball will go up.
C. The ball will stay at the
same level.
There is a lot of talk about the north polar
ice cap melting. When it melts what will
the result be on sea level?
A. It will rise.
B. It will fall.
C. It will stay the
same
A large chunk of ice is floating in water in
a bucket. When it melts what will the
water level in the bucket do?
A. It will rise.
B. It will fall.
C. It will stay the same
Two identical glasses are filled to the
same level with water. One of the two
glasses has ice cubes floating in it.
Which glass weighs more?
A. The glass without
ice cubes.
B. The glass with
ice cubes.
C. The two weigh
the same.
D. There is not enough
information to decide.
Two identical glasses are filled to the
same level with water. One of the two
glasses has ice cubes floating in it.
When the ice cubes melt, in which glass
is the level of the water higher ?
A. The glass without
ice cubes.
B. The glass with
ice cubes.
C. It is the same
in both.
D. There is not enough
information to decide.
Two balloons are connected by a pipe
with a valve. When the valve
is opened, what will happen?
1. The big balloon will get smaller and the
small get larger until the two are equal.
2. The big balloon will get larger and the
small get smaller until the small one is
very small.
3. Something else
will happen.
Blood flows through a coronary artery
that is partially blocked by deposits
along the artery wall. Through which part
of the artery is the flux (volume of blood
per unit time) largest?
A. The narrow part
B. The wide part
C. Same in both
Blood flows through a coronary artery
that is partially blocked by deposits
along the artery wall. Through which part
of the artery is the speed of the blood the
largest?
A. The narrow part
B. The wide part
C. Same in both
You can readily observe that when you run water
from a faucet at a moderate steady
flow rate, the stream of water narrows as it
descends. This implies that the speed of
the water at point 2 is _______ the speed
at point 1. Which best completes the sentence?
A. greater than (>)
B. less than (<)
C. equal to (=)
The main blood vessel carrying blood out of your heart
is the aorta. It carries blood down towards the legs.
In your abdomen it splits into two, the common iliac
arteries. The diameter of a typical aorta is 2 cm,
while the iliac arteries typically have diameters of about
1 cm. A typical value for the speed of the blood in the
aorta is vA = 30 cm/s when the heart is contracting.
While this is occurring, the speed of the blood flowing in
the iliac arteries will be closest to
A.
B.
C.
D.
E.
F.
120 cm/s
60 cm/s
30 cm/s
15 cm/s
7.5 cm/s
It’s not close to any of these.
Smoking tobacco is bad for your circulatory health. In an
attempt to maintain the blood’s capacity to deliver oxygen,
the body increases its red blood cell production, and this increases
the viscosity of the blood. In addition, nicotine from tobacco causes
arteries to constrict. For a nonsmoker, with blood viscosity of
2.5 × 10–3 Pa·s, normal blood flow requires a pressure difference of
8.0 mm Hg between the two ends of a certain artery. If this person
were to smoke regularly, his blood viscosity would increase to
2.8 × 10–3 Pa·s, and the diameter of his artery would constrict by 10%.
Assuming the pressure difference has not changed, which of the two
effects would have a larger effect on the amount of blood flow?
A.
B.
C.
D.
E.
The change in viscosity.
The change in diameter.
The effects of the two changes would be equal.
Neither would have an effect on the flow.
There is not enough information to tell
Construct the two combinations of coffee
straws as shown in the figure below. Fill
your lungs with air and blow as hard as
you can through each one.
Which did you find?
A. Arrangement A was
faster.
B. Arrangement B was
faster.
C. Both were the same.
A.
B.

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