OpenSciEd Unit 7.6 · Lesson 10 · 10.B
Look for: What evidence do you have that H2O is produced?
From Teacher Edition
Facilitation guidance from the lesson plan — what to notice in student thinking and how to respond while teaching.
Building towards
10.B.2 Ask questions to clarify whether the CO2 in the atmosphere can come from burning fossil fuels for energy.
What to look / listen for
students asking each other for evidence for the products of the combustion of fossil fuels such as:
What evidence do you have that H2O is produced?
How do you know the H2O wasn’t in the air to start with?
Do you have evidence beyond the humidity sensor values?
What evidence do you have that CO2 is produced?
How do you know the CO2 wasn’t in the air to start with?
students being skeptical because there is not sufficient evidence to convince them that fossil fuels in general produce CO2 and water when they burn;
students requesting or asking questions to get more evidence to support their findings—evidence that is sufficient to make a claim that CO2 and water are products of the combustion of a variety of fossil fuels; and
students recognizing that energy is a product of the combustion reactions, as well as matter that comes from the reactants.
What to do
Encourage students to ask each other questions, especially if the student responding is vague or gives an incomplete answer. Students should be asking questions of each other to clarify any claims or the evidence they have collected. Some students may need sentence starters to help them frame their questions. If your students need this support, write a few sentence starters on the whiteboard. Some examples of starters include: What do you mean by________? What evidence do you have that____________ is true? How do you know _____________?
Return to general chemical reaction. Display slide Q. Say, We have burned two different fossil fuels and have gotten similar results. Are you comfortable with saying that CO2 and water are two products of the reaction? Students may all be convinced but you may have some who are not. The teacher reference, Burning Fuels Instructions, gives suggestions for other tests with additional fossil fuels.
Say, Can we add products to this reaction that we started with? If some students are not convinced that this reaction can be generalized, write “butane” and “methanol” underneath “Fossil Fuel” so that you honor their skepticism but can move ahead.
(reactants)
(products)
Fossil fuel + oxygen (O2) →
CO2 + water