Analyzing Vehicle Emissions Lab for Biology & Environmental Science
A couple of weeks ago my Grade 12 IBDP Biology students were analyzing carbon dioxide and particulate matter emitted from a variety of different teacher's vehicles on campus as part of our study of climate change (Subtopics 4.3 & 4.4 in the old syllabus) and I of course, posted pictures on my Instagram. One of my follower's expressed interest in the lab and asked for information about it, and so this blog post was born! I am always eager to share resources, ideas and strategies with my colleagues from all over the world, so if you are teaching Integrated Science, Environmental Science (or IBDP ESS) or Biology this lab can be used in your course!
There are two versions of this lab that I will share, the first is useful if you don't have access to Carbon Dioxide sensors, or you only have a couple and you would like to use pH indicators as a way to estimate carbon dioxide levels. The second uses carbon dioxide sensors such as those from Vernier as a way to collect quantitative data regarding carbon dioxide levels which is really nice if your school has enough equipment to facilitate such a lab.
Version 1: Without a Carbon Dioxide Probe
This version of the lab can be done with pH indicators such as Bromothymol blue, Methylene blue or Bromophenol blue, it works on the premise that adding carbon dioxide to water will decrease its pH and it will show as more or less acidic using a pH indicator. You could also try this with a pH probe, although I haven't done so. The idea is that a significant sample of the vehicle exhaust is collected in a bottle and then carefully extracted using a syringe and then injected into a pH indicator solution (use the cards below here to help). This is not a particularly reliable method, but it does help students compare different vehicles and connect carbon dioxide production with acidification.
Version 2: With a Carbon Dioxide Probe
If you have a few carbon dioxide probes this is a much more accurate way to compare vehicles, although I have found that the probes take a long time to get a stable reading, so be careful to allow enough time for this. We ended up only doing one trial per vehicle with this method last time I did this lab since it took so long to get an accurate reading.
Tips & Tricks for this lab:
Ask your colleagues a week or so in advance if they would like to have their vehicles tested
Use a loop of paper stapled around the keys of each car to keep track of which is which, I put the owner's name, the car make, model & colour as well as their classroom number (see image above)
Be certain that students don't breathe in a large amount of fumes, you will want to make sure you do this lab outside and that students turn away from the exhaust as they collect the samples
Don't put the slide with petroleum jelly too close to the exhaust or the heat will melt the jelly and your data will be lost
use a Google Sheet like this one to help your class to share data, you can also see a sample of the data we collected this year
Most of all, have fun with your students & enjoy getting outside connecting the carbon cycle to the real world!
As always, thanks for reading teachers, travelers and curious souls of all kinds.
The Roaming Scientist
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