Lesson 1: Carbon Content of Fuel Combustion
The first activity that the students will participate in is the mathematical calculation of the mass of carbon dioxide that is produced from a given amount of gasoline. I want them to understand exactly how much carbon dioxide pollution comes from the combustion of gasoline as a motor fuel. This is critical to engage them in understanding that the carbon from fossil fuels has been locked away from the atmosphere for millions of years, and that by combusting gasoline they are releasing carbon which has been sequestered in the Earth's crust. I want them to get an idea of just how much pollution they themselves create every day, in order to get them interested in the possible solutions they will be researching. Based on the Law of Conservation of Matter, which states that matter may be neither gained nor lost in a chemical reaction, students will calculate the amount of oxygen required to fully combust gasoline. They will also calculate the mass of Carbon Dioxide and water vapor that is created in the combustion process.
The essential learning from this activity is that the combustion of gasoline produces a large quantity of carbon dioxide as a product. The students will most likely be surprised at the amount of carbon dioxide that is produced from the combustion of gasoline.
Activity 1: Calculation of Carbon Dioxide Pollution from Gasoline Combustion
The actual activity is fairly straightforward. Students will receive a handout with a structural drawing of a hypothetical gasoline molecule (See Appendix 2). They will be informed that a 100% combustion efficiency is obtained, to simplify the calculations and make their calculations uniform.
Students will work in pairs or groups of three. They will be told that the products are carbon dioxide and water, and will first need to write an equation that shows the combustion of gasoline. The student groups will then have to balance the equations, and derive the number of moles of carbon dioxide that are produced per mole of gasoline combusted.
Activity 2: Calculation of the Carbon Dioxide Pollution Produced per Student, Efficiency Calculations
Now that students understand how much carbon dioxide is released from the combustion of gasoline, I will get them to think about fuel efficiency and how they can lower the amount of carbon dioxide that they produce as they drive.
I will keep the students in the same groups as they were in previously for this activity.
I will randomly assign a number that represents the miles per gallon average that their vehicle gets. I will tell them all that they drive an average of 10,000 miles in a year. They will then have to calculate the amount of carbon dioxide that they produce from their vehicle. Once they have calculated their carbon dioxide emissions, I will have them estimate the carbon dioxide emissions for the United States if one million people drove their type of automobile for the same number of miles each year.
I will ask them to come up with some variables that are probably not taken into consideration for this calculation. For example, not everyone drives 10,000 miles per year. The students will write their ideas in a sheet of white paper to be hung around the room as they discuss their answers.
Homework Assignment:
I will assign each student to research ways in which to increase the mileage of their assigned automobile. Methods will need to be realistic and easily achieved by the average motorist.
When the class reconvenes during the next block, I will have the students sit with their group. They will discuss the various ways that they have discovered to raise their automobiles mileage. The group will then prioritize what they feel are the ten best ways to increase gas mileage. Once all of the groups are ready, they will stand and present their findings to the class. The class will then prioritize a list of conservation tactics that they feel are feasible. I will take the class out to the parking lot and show them easy ways to increase their fuel mileage. For example, I will point out where a typical air filter is located, and show them how easy it is to check the air pressure in their tires. At some point I will have them create mini posters to hang throughout the school to advertise the ways to conserve when using an automobile.
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