Reflection: Classroom Setup How Much Gasoline Do You Really Use?  Section 3: Explain
The easiest, most timeefficient manner to calculate CO2 emissions is with the CO2 calculator. The organization called Carbon Offsets to Alleviate Poverty has a CO2 calculator. I have used this site as a modification for the struggling math students and absent students.
When the students do the math, my best defense is a good offense. I like to read about the formula to get a better idea for myself how to teach it. To help with some of the CO2 calculations, Slate Magazine wrote an article explaining the formula. In addition the Pedestrian and Bicycle Information Center produces a document of FAQ's that has been helpful for me.
How Much Gasoline Do You Really Use?
Lesson 6 of 7
Objective: Students will be able to use a mathematical model to determine personal gasoline use and the costs involved.
Big Idea: Here's a great way to hit home the costs of every day driving habits. Students analyze family driving habits to calculate the environmental impact and the cost in money.
Engage
Everyone in my class has had experience with driving errands. My strategy is a student led discussion, so this is the time to let students tell their stories to one another. I hand out the questions, "What are your family's driving habits?" and "Where does your family drive to most often?" on strips of paper. Students write their responses on the strips.
Then I ask students to generate a list of questions or comments they can ask one another in a discussion. I use, "What you said reminded me of...." "I wonder...." "I go there and we...." If a student has a different response, they can use it. I tell them this is like the game Hot Potato. They want to stay in the conversation as long as possible but one person cannot talk for too long. My intention is to involve all students in a conversation to develop background knowledge, share common experiences, and to learn from one another.
Explore
In the lesson my strategy is to use mathematical analysis to determine how much carbon dioxide the student's family emits.
I present the following grid:
Prediction Grid
Destination Miles Gallons of gas Cost
I ask students to use their strips and conversations to call out places they drive for vacation and occasional but regular visits. I ask them to predict the miles, gallons of gas, and the cost. They usually say they don't know. I say guess and sometimes students will come up with completely wrong predications. Resist the urge to correct them.
Be sure to use proper nouns such as Safeway (instead of grocery store) or St. Mary's (or church) for destinations. At the end of the lesson, you will pull out these presentation boards and compare predictions with the actual results.
My strategy is to integrate technology and promote an understanding of mathematical models of transportation habits. I have students fill in the Destination column on the Transportation Analysis. Using the presentation boards from Engage, I direct students to fill in 10 destinations.
Destination 
Miles 
Miles per gallon 
Gas used (gallons) 
Cost of gas Dollars/ cents 
Cost of Trip Dollars, cents 
1 





2 





3 





4 





5 





6 





7 





8 





9 





10 





TOTALS 
A= 

B= 
XXXXXXXXX 

Resources (2)
Explain
I ask students to go to the computer and open Map Quest. I like Map Quest because students type in their home address and the computer remembers it. I ask them to write in the destination. If they do not know the address, I encourage them to look it up on the computer. The computer will get to things like St. Barbaras Church but place like McDonald's may need an address. Students will say I don't know my grandma's address. I'll ask them to choose something close by as a destination.
Students then find out the miles per gallon of their cars. I usually ask students to find out the type of car their family drives and its gas mileage as a homework assignment. Some students don't complete the assignment so I use the site called Fuel Economy. On this site the government has a handy tool in which students can select the year, make, and model of cars to determine the mileage. Sometimes students don't know their cars so I ask them to use a friend's. The site also has pictures so if they know the manufacturer they look at the pictures to find it.
To calculate the price per gallon, students use current gas prices for regular gas. Many of my student families have Hybrid vehicles. I say, "That is so cool! Now we can compare a hybrid against a nonhybrid!"
Students calculate the costs to drive to destinations. They find the totals and calculate the amount of CO_{2 }emissions their driving habits contribute to Climate Change. The Environmental Protection Agency calculates 19.4 pounds of CO_{2 }emissions PER GALLON of regular gas and 22.2 pounds of CO_{2 }emissions PER GALLON of diesel fuel.
Resources (1)
Resources (1)
Resources
Expand
On the second page students will be thinking about changing their driving habits. My strategy is to ask students to estimate the impact of a change. I ask for five alternative destinations and ask students to recalculate using the new destination. There are several places students can not change, church, Grandma's etc. I ask students to examine their shopping errands. In my community we have a Target, WalMart, and Costco a distance away. I ask students to change those errands to Walgreens, CVS, or other closer stores. The students complain, "But they are more expensive!" My response is, "Calculate the gas price to see how much it costs to get to the big box stores. find out for me if they are still worth it." My intention is to create a situation in which students understand how driving to the big box stores to get a deal, is not always the best idea.
Families regularly go on trips of three destinations. Students say, "But we go to three places at once." I acknowledge the good habits and ask how they would change the data to be more reflective of their practices. I have also said, "When you do your final calculations, remember that and in your reflection explain what you think the difference might be."
Students determine the total miles of the original destinations vs the changed destinations. they calculate the change in gas cost as well as the difference in CO_{2 }emissions.
Evaluate
Whew! If you did the math and you made it to the reflection point, congratulations!
My strategy is a Mathematical Analysis of the data. My intention is to ask the students to estimate the impact of their driving habits on the environment.
To evaluate the learning, my strategy is a Reflection.
Answer the following questions. Include data from your analysis worksheet.
 What surprised you about your results?
 What was most interesting about your data?
 Name two things you can do to lower your family's carbon dioxide emissions.
In the film below, one of my students explains his worksheet. He was quite nervous and mistakes that I spoke him about afterwards.
MS ESS35 Ask questions to clarify evidence of the factors that have caused the rise in global temperatures over the past century.
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