Facts About Gases
Casey and Jesse are learning about gases:
Three Facts About Gases
1. Gases are made up of lots of tiny particles
2. The particles are too far apart to exert any force on
each other
3. The particles move around rapidly in all directions –
up, down, and sideways
A.) Jesse says: “I was learning about gases yesterday. Gases fill the
whole space they are in. You can tell that from Fact #1.” What is Jesse
claiming about gases? Circle one:
1. “I was learning about gases yesterday.”
2. “Gases fill the whole space they are in.”
3. “You can tell that from Fact #1.”
4. None of the above
Note: The numerical Levels indicated in the scoring rubrics were for research
purposes. Higher Levels indicate higher quality argumentation. We encourage
you to use a scoring scheme that matches your present goals for students.
Part A
Argumentation Level 0b: Identifying a claim
Level
1
0
Description
Student selects option 2 – “Gases fill the whole space they
are in.”
Student selects any option besides 2
B.) What is Jesse’s reason? Circle one:
1. “I was learning about gases yesterday.”
2. “Gases fill the whole space they are in.”
3. “You can tell that from Fact #1.”
4. None of the above
Part B
Argumentation Level 1b: Identifying reasoning
Level
1
Description
Student selects option 3 – “You can tell that from Fact
#1.”
0
Student selects any option besides 3
C.) Casey disagrees with Jesse about why “gases fill the whole space they are in”.
Who’s argument makes more sense?
Check the
better argument
Jesse: “Fact #1 explains it because if the gas particles are tiny, they
will float up and fill the whole space.”
Casey: “Fact #3 explains it because if gas particles move in all
directions, then they will move around into the whole space.”
D.) Explain why that argument makes more sense.
The argument makes more sense because…
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Part C and D
Argumentation Level 2b: Constructing a one-sided comparative argument
JESSE’S POSITION: GASES FILL THE WHOLE SPACE THEY ARE IN
JESSE’S ARGUMENT: Jesse appeals to Fact #1 (i.e., gases are made of lots of tiny particles). Jesse
argues that, “Fact #1 explains it because if the gas particles are tiny, they will float up and fill the whole
space.”
CASEY’S POSITION: GASES FILL THE WHOLE SPACE THEY ARE IN (same position as Jesse)
CASEY’S ARGUMENT: Casey appeals to Fact #3 (i.e., The particles move around rapidly in all
directions – up, down, and sideways). Casey argues that, “Fact #3 explains it because if gas particles
move in all directions, then they will move around into the whole space.”
Acceptable reasons for why Jesse’s argument is better:
[NOTE: Jesse’s argument is scientifically incorrect, so what follows are possible misconceptions]

Sure, the motion is random, but just because it is random doesn’t mean that the random
motion will quickly disperse throughout the container the gas occupies. Maybe the random
motion is confined to a smaller region of the container? [note: this would be a critique of
Casey]

Gases are made of particles, and when particles are pressed next to each other, there still
may be empty space between them. Hence gas particles cannot occupy all the space in which
the gas is contained. [note: this would be a critique of Casey]

Just because particles are small doesn’t mean they will disperse throughout the container
that holds them. After all, solids are made out of tiny particles too, but solids do not
necessarily occupy the entire space of the container that holds them. [note: this would be a
critique of Casey]
Acceptable reasons for why Casey’s argument is better:
[NOTE: this is actually the scientifically correct position]

Gases do not just float in one direction (e.g., up)

Gases do not “float” in the first place – even very small objects experience gravity insofar as
they have mass

If gases “float” opposite of gravity, eventually the gas particles would only occupy the top of
the container
Level
3
Description
Student constructs a one-sided
comparative argument, by identifying
(1) who has the better argument AND
(2) explaining why it is the better
argument
In order to completely satisfy (2), the
student answer could perhaps refer to the
quality of evidence, the quantity of
evidence, the strength of connection
between claim and evidence, or perhaps
the consistency with outside world/their
own experiences. Appealing to all of
these criteria is not necessary, but to get a
Level of 3 the student needs to provide an
acceptable reason for why the argument
they selected is better. Please see above
Empirical Example
[chooses Casey] Casey’s make more sense
because particles don’t just float up, they float
around. Note: While similar to repeating
Casey’s argument, this answer actually
critiques Jesse’s argument by correctly noting
that gas particles move in all directions, not
just up
Chooses Jesse] Fact number 3 doesn’t mention
particle size so if the particles were big there
would be empty voids that can’t be filled in since
this argument mentions that they are small they
can fill the space
Note: States a good objection to Fact 3,
namely that particle size is not addressed and
that large particles would have gaps, thereby
not filling the space
[chooses Casey] The argument makes more
in boldface for examples of what counts
as acceptable.
2
Student attempts to argue for whether
Jesse or Casey has the better argument
BUT
Student provides an only partially
acceptable reason for why the argument
they selected is better. Please see above
in boldface for examples of what counts
as acceptable.
1
Student makes an authentic attempt to go
beyond the givens of the problem and
argue for whether Jesse or Casey has the
better argument
sense because Jesse says that if they float up it
will take up all the space. But that would only be
in a single direction. While if you move in all
directions you’d take up all the space.
T506 [Chooses Casey] Casey made more sense
because it’s like smoke when you see them move
around Note: This appeal to everyday
experience is not a complete justification, but
still an attempt to go beyond the givens of the
problem.
[Chooses Casey] If the atoms did not move it
would be a solid Note: Not scientifically
correct, but still an attempt to go beyond the
givens of the problem.
[Chooses Casey] They can explain or spread due
to their mass and form Note: explain or spread
due to mass and form” is incoherent – a lot
would have to be inferred from this statement
to give the student a higher Level
BUT
Student provides an incoherent
explanation and/or the student appears to
misunderstand the problem.
[Chooses Jesse] Atoms move, and not all gases
are made of a lot of atom Note: attempted
explanation is authentic, but not coherent
[Chooses Jesse] If it took up a whole space it
wouldn’t have enogh room to move up, down,
and sideways Note: this an example of the
student misunderstanding the problem, as the
student chooses Jesse but then argues against
the gas particles taking up the entire space of
their container, which is precisely Jesse’s
position
[Chooses Casey] Because gases do move around
it will move Note: attempted explanation is
authentic, but not coherent
0
Student does not explain why an
argument is better.
[Chooses Casey] Because there moving all over
Note: just repeats Casey’s argument
This includes a student claiming that one
argument is better, but providing no
justification at all as to why it is superior
(e.g., “Jesse’s/Casey’s argument is better
because it’s right”)
[Chooses Casey] Fact 3 makes more sense
because as particles move around they fill up the
spaces
This also includes a student merely
[Chooses Jesse] Because they explaining Note:
repeating information already provided to
them (e.g., simply repeating the
arguments advanced by Jesse and/or
Casey).
No real reason provided
E.) Explain why the other argument make less sense?
The other argument makes less sense because…
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Part E
Argumentation Level 2a: Providing a counter-critique
JESSE’S POSITION: GASES FILL THE WHOLE SPACE THEY ARE IN
JESSE’S ARGUMENT: Jesse appeals to Fact #1 (i.e., gases are made of lots of tiny particles). Jesse
argues that, “Fact #1 explains it because if the gas particles are tiny, they will float up and fill the whole
space.”
CASEY’S POSITION: GASES FILL THE WHOLE SPACE THEY ARE IN (same position as Jesse)
CASEY’S ARGUMENT: Casey appeals to Fact #3 (i.e., The particles move around rapidly in all
directions – up, down, and sideways). Casey argues that, “Fact #3 explains it because if gas particles
move in all directions, then they will move around into the whole space.”
Acceptable reasons for why Casey’s argument is WORSE:
[NOTE: Jesse’s argument is scientifically incorrect, so what follows are possible misconceptions]

Sure, the motion is random, but just because it is random doesn’t mean that the random
motion will quickly disperse throughout the container the gas occupies. Maybe the random
motion is confined to a smaller region of the container? [note: this would be a critique of
Casey]

Gases are made of particles, and when particles are pressed next to each other, there still
may be empty space between them. Hence gas particles cannot occupy all the space in which
the gas is contained. [note: this would be a critique of Casey]

Just because particles are small doesn’t mean they will disperse throughout the container
that holds them. After all, solids are made out of tiny particles too, but solids do not
necessarily occupy the entire space of the container that holds them. [note: this would be a
critique of Casey]
Acceptable reasons for why Jesse’s argument is WORSE:
[NOTE: this is actually the scientifically correct position]

Gases do not just float in one direction (e.g., up)

Gases do not “float” in the first place – even very small objects experience gravity insofar as
they have mass

If gases “float” opposite of gravity, eventually the gas particles would only occupy the top of
the container
Level
3
Description
Student constructs a one-sided comparative
argument, by identifying
Empirical Example
[chooses Jesse] If it floats up it won’t fill
the whole space. Only the top.
(1) who has the WORSE argument AND
[chooses Jesse] If the gas particles are
tiny, they would FLOAT UP. If they’re
just going to float up, there will be none
left on the bottom. How will it fill up the
whole space if there are none left at the
bottom?
(2) explaining why it is a WORSE argument
2
In order to completely satisfy (2), the student
answer could perhaps refer to the quality of
evidence, the quantity of evidence, the strength of
connection between claim and evidence, or perhaps
the consistency with outside world/their own
experiences. Appealing to all of these criteria is not
necessary, but to get a Level of 3 the student needs
to provide an acceptable reason for why the
argument they selected is WORSE. Please see
above in boldface for examples of what counts
as acceptable.
Student attempts to argue for whether Jesse or
Casey has the WORSE argument
BUT
1
Student provides an only partially acceptable
reason for why the argument they selected is
WORSE. Please see above in boldface for
examples of what counts as acceptable.
Student makes an authentic attempt to go beyond
the givens of the problem and argue for whether
[chooses Casey] If they’re always
moving, there will always be a gap due
to movement
[chooses Casey] The other argument
makes less sense because if you only
float up, you only fill a part of the
space.
[chooses Jesse] If it just floats, it won’t
move unless something does. Note:
Student begins to make an argument
against Jesse’s “floating” scenario,
but the argument is incomplete
[chooses Jesse] Jesse doesn’t make
much sense because gas particles just
Jesse or Casey has the WORSE argument
BUT
Student provides an incoherent explanation and/or
the student appears to misunderstand the problem.
don’t float and fill the whole space
Note: Student misunderstands the
question, because both Jesse and
Casey agree that gas particles fill the
entire space that encloses the gas
[chooses Jesse] Gas doesn’t stick
together so why would it go all into one
space Note: Student misunderstands
the question, because both Jesse and
Casey agree that gas particles fill the
entire space that encloses the gas.
Because only some of it goes in the
thing
0
Student does not explain why an argument is
WORSE.
This includes a student claiming that one argument
is WORSE, but providing no justification at all as
to why it is INFERIOR (e.g., “Jesse’s/Casey’s
argument is worse because it’s wring”)
This also includes a student merely repeating
information already provided to them (e.g., simply
repeating the arguments advanced by Jesse and/or
Casey).
They are gases are they
It sounds confusing because its
basically saying it it make’s no sense!