Bubbles in Water

Brian and Joe are looking at the water boiling in the pan on the stove.

Brian says that the bubbles are made of air that gets pushed out of the water when the water gets hot.

He argues that he knows that there is air dissolved in water because fish are able to breath the oxygen in the water.

Joe says that the bubbles are made of water that has turned into a gas – water vapor.

Joe agrees with Brian that fish are able to breathe oxygen in the water. But the pan has been boiling for 10 minutes and it is still bubbling just as much as it was at the beginning. If Brian was right, wouldn’t the air be gone by now?

  1. What idea is Brian arguing for?

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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 1
ArgumentationLevel 0b: Identifying a claim

Level / Description / Empirical Example
1 / Student answer refers to “air.” / air is dissolved in the water
That there is air in water
0 / Student does not identify Brian’s argument / bubbles pushing out of the pan.
bubbles
  1. What is the reason Brian gives to convince Joe that he is right?
  2. Fish are able to breath the oxygen in the water
  3. Bubbles are made of air
  4. The pan has been boiling for 10 minutes and it is still bubbling
  5. Hot water boils

Part 2
ArgumentationLevel 1b: Identifying reasoning

Level / Description / Empirical Example
1 / Circles (a)
0 / Circles (b) (c) or (d)
  1. What ideais Joetrying to argue for?

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Part 3
ArgumentationLevel 0b: Identifying a claim

Level / Description / Empirical Example
1 / Student answer refers to “gas” or “water vapor” / Bubble turned to gas
bubbles in water is gas
0 / Student does not identify Joe’s argument / how it affect the it
When water gets hot, it bubbles
  1. What is the reasonJoe gives to convince Brian he is right?
  2. Fish are able to breath the oxygen in the water
  3. Bubbles are made of air
  4. The pan has been boiling for 10 minutes and it is still bubbling
  5. Hot water boils

Part 4
ArgumentationLevel 1b: Identifying reasoning

Level / Description / Empirical Example
1 / Student circles (c)
0 / Student circles (a), (b) or (d)

5. Briansays that he knows that water is made of hydrogen and oxygen. The bubbles are caused by the water breaking down to produce hydrogen and oxygen that are both gases. These form bubbles like the gas in soda.

Joe is unconvinced. He remembers observing that the saucepan lid became covered in water drops as the water continued to boil. How could he use this observation to convince Brian that he is wrong?

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Part 5
Argumentation Level 2a: Providing a counter-critique

Level / Description / Empirical Example
2 / Student provides a complete and accurate counterargument, including some kind of comparison of the two ideas.
Student makes an argument that it’s state change; therefore, it can’t be a chemical change.
If water is collecting on the top of the lid, then the most likely thing that is bubbling out of the liquid water is gaseous water.
Brian is wrong because if it were oxygen and hydrogen, they wouldn’t collect as water on the top of the lid.
If there are water drops on the pan it suggests that the oxygen and hydrogen didn’t split / None found
1 / Student provides a plausible argument, but might be incomplete or not 100% accurate.
Student makes an argument that it’s a state change. / The water vapor evaporated and landed on the lid
The water boils so it evaporates
0 / Student provides an incorrect counterargument or fails to answer the question. / It is because the water has been boiling for more than 10 minutes
Try the experiment again.