Air pollution is a topic that fits into almost all science content areas. Teach biology? You teach the water and carbon cycles. Environmental science? Climate change and smog. Earth and space science? Layers of the atmosphere and ozone. Chemistry? Water + CO2 = carbonic acid. (Side note: My students recently tested the pH of different water sources, and were blown away that the pH of our rainwater sample was 5.4). I think it is telling that our air and atmosphere are woven into so many different sciences. Air is vital, so let's talk about it with our students!
I recently did a mini unit with my students on urban ecology. We were learning about the effects of urbanization on ecosystems, and pollution and urban heat islands came up in our discussions. (You can read my blog post about urban heat islands here). Here in Phoenix it is relatively easy to see how polluted our air is, all you have to do is drive up a hill and you will see the layer of haze that sits over our city of 1.6 million people. We discussed the health effects of air pollution and I wanted my students to have a visual of what they were breathing in. You can buy fancy (and expensive) sensors that will give you data readings of all the particles in the air, but I found an easy way for students to see the particulate matter floating around.
You will need:
This lab is super easy. All you have to do is have students smear a thin layer of petroleum jelly across the center of a glass microscope slide with a clean cotton swab. If you want your students to have quantitative data at the end of the experiment, gridded slides are ideal (See image). No worries if you only have plain slides.
Students got to choose where they wanted to leave their vasaline-covered slide for 24 hours. I had some students leave the slides in the classroom and others left their slides outside. (Tip: I had students set them in a petri dish and label them with their initials so we could track them down easier the next day. Also, if students choose to leave them outside, find a location on your school campus where they won't get disturbed). In the next 24 hours, any particulate matter floating around will land on the slide and stick to the petroleum jelly. If you want easier cleanup, you can also try putting a piece of double sided tape on the slide instead.
The next day, students retrieved their slides and viewed them under the microscope. I had them switch slides with their neighbors so they could compare indoor vs. outdoor slides. As you can see from our results pictured below, there was generally a lot more particulate matter on the outdoor slides. I had students draw what they observed and do a little math to calculate the particle deposition rate. If you are interested in checking out the lab write up, click here.
Remember when I said there was generally more particulate matter outside than inside? Are you ready to be completely grossed out? I had a student that decided to hang his slide from the ceiling by the classroom air vent... and this is the image that ensued. Can you say "time to change the air filter?"
I hope your students enjoy this lab as much as mine did! It was definitely eye opening for them to see the microscopic matter going into their lungs.
I currently live in Phoenix, AZ, which is the 6th largest city in the United States. Considering our large population size and desert climate, we have a huge problem with heat. In the summer it is not uncommon for the temperature to stay above 100F all night. It can be miserably hot!
An urban heat island is an urban area that has a much higher temperature than the surrounding areas. Students probably haven't heard the term coined before, but can easily explain it to you. If you ask them why downtown Phoenix is hotter than some of the surrounding pockets of town, or ask them why it's cooler to stand under a tree than under a metal awning, they can explain it to you. As I was preparing to teach this concept to my students, I found (and created) a few resources you may want to check out!
Urban Heat Island Lab
In this activity, have your students head out around your school campus and measure the temperatures of different materials. Students will compare surfaces such as cement, asphalt, dirt, and grass in the sun and the shade. Students can brainstorm ways to improve the school campus and lower the overall temperature (and electric bill!) of the school.
ASU Ecology Explorer Lessons
Arizona State University has a few lessons on urban heat islands that are great! This first lesson uses thermal images to teach students that urban heat islands are a night-time phenomenon, opposed to day time. Students will compare thermal images and try and figure out which ones were taken during the day and which were taken at night.
This second lesson also uses thermal images, but students have to predict which object in the picture would be the hottest, and which would be the coolest. (If you don't have access to a color printer, you can just project the images on the board).
Climate Central Interactive
Do you live in an urban heat island? This fun interactive looks at 60 cities across the US and gives you data on each one. Check it out and see if your city is listed!
Start a citizen science project, where your students collect data about temperatures in your area, brainstorm ideas to mitigate the problem, and reach out to scientists, politicians, or even school board members to try and make a difference! It could be something as simple as planting a tree on campus or taking them to a community garden, to something larger like having students apply for grant money to have solar powered cell phone charging stations installed. If you let the students decide what impact they want to make their work ethic may surprise you!
(One great nonprofit organization that plants trees is onetreeplanted.org. They plant a tree for every dollar donated!)
With climate change being a current global crisis, we have an obligation to teach students how to make more sustainable decisions. If every one of your students made a small change in their front yard we could see incredible results. Who knows, you might have a student in your class that will major in urban planning or sustainability!