For my ADI, I intend to focus on the learning standard 3221.2.7 in Chemistry:comprehension of the relationships between pressure, volume, and temperature in determining the behavior of a gas.
Step 1:
Beforehand, students should have a basic understanding of some of the behaviors of gases (namely, the tendency of a gas to expand to fill its container) and students should also have a basic understanding of how solids and liquids differ in this behavior. Prior instruction should also define in a basic matter volume, pressure, and temperature. This experiment would serve as an introduction to the ideal gas law, and the ultimate objective of this experiment would be for students to be able to derive the ideal gas law and be able to explain why each variable affects gaseous behavior in the way it does.
As a note, discussion of gases will be kept primarily in terms of ideal gases; for a high school course of chemistry, while it is important to know the shortcomings of the ideal gas law, I do not think it is helpful to complicate the experiment with discussions of van der Waals gases or other models of gaseous behavior. Ideal gas assumptions/approximations should suffice for the purpose of the course and the learning standard.
Problem- How do pressure, volume, and temperature affect each other in a gas? What does this tell us about the behavior of a gas in general? How would you write an equation that expresses these behaviors (hopefully, by the end of it students may be able to answer how the amount of particles present will also be a relevant factor)?
Step 2:
Experiment Setup- Students will work with online demos, initially being shown individual screenshots of pressure, temperature, and volume at various levels, and then be allowed to work with the demo software itself. Students should be able to work by changing one variable, holding one constant, and seeing how this change affects the third variable. Students should, as the activity progresses, start to be able to make rudimentary predictions of what will happen as a certain variable such as temperature will change.
Step 3:
Students would be encouraged to use the simulation itself in order to aid explanations. Whiteboards/poster paper would be used in order for students to map out what relationships between the variables they had observed; students should also use this space to present preliminary explanations of why changing a variable causes another to change and in what way. The discussion should ideally be focused on why students THINK these relationships are linked. Students would also be encouraged to share their prototypical explanations of the ideal gas law, if possible.
Steps 4-8:
From here, much of the work is based on students evaluation and discussion; for ease of reading, it will all be covered here. Students will have to explain/defend their theories to their peers, first in small groups as the class will come together in the end of the project. Students should use this time to refine their own models of the ideal gas law, and be prepared to justify why they don't believe in changing a model if it conflicts with another group member's. Students should NOT necessarily come to a consensus or copy off of one model, students should use communication with their peers as a way to gather information. Students should then formally type their observations/arguments and have them distributed anonymously to their peers, as per the ADI method. From here, students should revise their models based off of the feedback of their peers, and prepare to present their findings to the class.
At the end of this (with teacher instruction if necessary), students should have an understanding of the ideal gas law as well as why volume, pressure, and temperature all relate to each other in the way they do and be able to articulate this to the teacher and their peers.
I think the ideal gas law is a really accessible topic for students to understand through an online activity, especially in the manner you discussed. I wonder how diverse the students tentative models will be if they are all given the same online demos to observe/manipulate? Are there way this activity can be altered based on the level of student knowledge?
ReplyDeleteOverall, I think this example is great in its ability to incorporate so many elements beyond simply the Ideal Gas Law equations including computer literacy, math literacy (if students are challenged to mathematically compute the relationships between variables), as well as english literacy. This exercise can also benefit students when faced with test questions about gas laws because instead of just being told the relationships students discovered them themselves which is much more memorable.