Answer Key to Gases Task

Within the gases task, each question is designed to measure a specific level of the Particulate Explanations of Physical Change Learning Progression OR the Arguing from Evidence Learning Progression. The target level label shows the level that the question is designed to measure. A scoring guide follows each item with instructions for scoring open-ended responses along with the percentage of students who typically provide that response.

Arguing from Evidence Learning Progression

Level 3: Students at this level are able to argue from evidence, making claims, supporting the claims with evidence, and connecting them with reasoning. Students need support in constructing counter arguments and identifying which of two arguments is stronger.

Level 2: Students at this level are able to make claims and identify evidence. They need support finding reasoning to connect their claims to evidence.

Level 1: Students at this level are starting to understand how to argue from evidence. They may be able to make a claim and are beginning to learn to identify evidence.

Level 0: Students at this level need support making claims and finding evidence.

Particulate Explanations of Physical Changes (EPC) - Strand C: Arrangements and movements

Level 3: Can explain why a volume of ice contains fewer molecules than the same volume of water. Water molecules occupy more space when the water evaporates and they are moving more freely.

Level 2: Knows that a given volume of ice contains fewer molecules than the same volume of water.Knows that in ice the spaces between the molecules are empty.

Level 1: Can describe the arrangements molecules in ice, water and water vapor. Can describe the movements of molecules in ice, water and water vapor. Knows that a given volume of water vapor contains fewer molecules than the same volume of liquid water.

Target level : explanation of physical changes - arrangements and movements - level 2

A. The container above contains a gas. Why doesn't all of the gas stay at the bottom of the container?

All of the gas doesn’t stay at the bottom of the container because…

________________________________________________________________________________________________________

2 points: Student provides a mechanism of how the gas fills the container in terms of the motion of molecules or particles OR collisions (does not have to say "particles" or "molecules"). The answer has to get at how gases move.

1 point: Student provides an explanation in terms of the property of gases filling containers they occupy. The answer does not convey movement. AND/OR student provides partially correct molecular-level explanation.

0 point: Explanation in terms of the gas float or its density or other incorrect explanation.

Target level: explanation of physical changes - arrangements and movements - level 1

B. A gas is put into the bottom of the container. The container is then completely closed. At first, the gas particles are arranged like this:

After several minutes, which of the following arrangements of gas particles is most likely?

The most likely arrangement is...

A

B

C

D

Target level: explanation of physical changes - arrangements and movements - level 2

C. At first, the gas particles are arranged like this:

You said the particles would be arranged like this after several minutes:

How do the particles go from where they start to where they finish?

The particles...

________________________________________________________________________________________________________

2 points: Student provides a complete explanation in terms of the colliding, bouncing, AND spreading out

and/or talks about random movement (or moving around in all directions or all over the place).

1 point: Student provides a partially correct explanation in terms of the particles.

0 points: Student provides an incorrect, off-topic, explanation.

Target level: Argumentation level 1b

D. Sally is thinking about the gas particles and she makes the following argument.

Sally’s Argument: I think the gas particles will be arranged like the picture shows below. My teacher told me the gas particles don’t attract each other. Since gas particles don’t attract each other, they would be spread out in the container.

What reason does sally give for her picture choice in her argument?

The reason in Sally’s argument is…

________________________________________________________________________________________________________

1 point: student correctly identifies reasoning OR the student explains the argument.

0 points: student does not correctly identify Sally's reasoning.

E1. Two students are talking about gases.

Their teacher tells them three facts about gases.

1. Gases are made up of lots of tiny particles.

2. Gases are less dense than liquids and solids.

3. The particles move around rapidly in all directions – up, down, and sideways.

Which student do you agree with more?

A. Johnny

B. Sally

E2. Which fact about gases best supports the student you agree with more?

1. Gases are made up of lots of tiny particles.

2. Gases are less dense than liquids and solids.

3. The particles move around rapidly in all directions – up, down, and sideways.

Target level: Argumentation level 1a

E3. Explain how the evidence you selected supports the student's answer. The evidence I selected best supports the student’s idea because…

_______________________________________________________________________________________________________________

2 points: NOTE: Score needs to reference whether the student selected Johnny or Sally AND the evidence.

Student provides a complete and logical warrant explaining how the evidence supports the claim (it explains the connection between the claim and the evidence)

The student has to reference the evidence (moving rapidly) and the particles spreading out, being in all parts of the container, or that it is not just at the top of the container (the opposite).

1 point: Student restates the claim and/or evidence or student provides a partial warrant.

0 points: Student does not provide a warrant and does not restate the claim or evidence or provides a nonsensical response.

Target level: Argumentation 2b

F. “I think [student’s] idea is better because…”

You said you agree with Johnny more than Sally. Why do you think Johnny’s idea is better?

I think Johnny’s idea is better because…

_______________________________________________________________________________________________________________

2 points: Student's justification includes evidence (which may be a restatement) AND reasoning.

1 point: Student’s justification includes evidence OR accurate reasoning. Student may refute the other argument.

0 points: Student's justification does not include evidence or reasoning. This may include restating the claim verbatim.

Target level: Argumentation level 2a

G. “I agree less with [student] because…”

Why do you agree less with Sally?

I agree less with Sally because...

________________________________________________________________________________________________________

2 points: Note: Reference who the student did NOT select for Item E1. Student identifies a flaw that is consistent with what is provided in the gases item AND explains why it is a flaw.

1 point: Student identifies a flaw that is consistent with what is provided in the gases item. The student provides a counter-argument (evidence or reasoning supporting the student they agree with).

0 points: Student does not identify a flaw.