OpenSciEd Unit 7.6 · Lesson 11 · 11.A
Look for: see the Key Ideas section above,
From Teacher Edition
Facilitation guidance from the lesson plan — what to notice in student thinking and how to respond while teaching.
Building towards
11.A Apply mathematical concepts to compare the rate of combustion and cellular respiration putting CO2 into the atmosphere to the rate for photosynthesis taking CO2 out of the atmosphere leading to an imbalance in the system.
What to look / listen for
see the Key Ideas section above,
students to apply the rates to make sense of the imbalance that occurs when comparing the rate of CO2 entering the atmosphere from combustion versus the rate of CO2 taken out of the atmosphere from photosynthesis,
- students use the rates to explain that a net of 8.5 GtC/yr is going into the atmosphere without an offsetting process to take it out.
- students may explain that the processes are not balanced.
- students may explain that when humans started to burn fossil fuels we created a change to the system.
What to do
During the discussion
If students need additional support, have them return to the graphs from Lesson 10 depicting population growth and energy use and discuss (1) what would we predict will happen to the combustion number given our population growth and needs for energy? and (2) What do we predict could happen to the photosynthesis number given land use choices we learned about in the Palm Oil Unit? Have students complete a third round of the dice game but with increased fossil fuel use so that, when they roll the dice, there is more opportunity to leave the fossil fuel reservoir. Have them complete a round with reduced fossil fuel use where there is only one opportunity (rolling a 6) to leave the fossil fuel location. The additional rounds may help students see that the rate of use of fossil fuels can greatly affect buildup of carbon atoms in the atmosphere.
In response to the exit ticket
Review the exit tickets before the assessment in Lesson 12. Depending on what you notice, consider allotting time to (1) look for patterns in responses and identify any partially correct or incorrect responses to inform your next steps. What you do will depend on the patterns you notice, (2) arrange students in groups of 3 with their individual exit tickets. Ask them to use ideas from their individual responses to craft a consensus statement to share with the class. They can exchange their consensus statement for evaluation by another group, and then make revisions.
Additional Lesson 11 Teacher Guidance
SUPPORTING STUDENTS IN MAKING CONNECTIONS IN MATH
CCSS.Math.Content.6.RP.A.3: Use ratio and rate reasoning to solve real-world and mathematical problems.
After 6th grade students should be familiar with unit rates. In this lesson, students use the unit rate of gigatons of carbon per year. Have your students compare rates for photosynthesis, cellular respiration, and combustion to make sense of the increase in carbon dioxide in the atmosphere. Have students compare the magnitude of combustion, which seems far less than the natural processes, yet there is no offset for this source of CO2.