Teaching cellular respiration in middle school is like trying to explain WiFi to your boomer parents – oversimplify it, and they think the internet is magic; go too deep, and you’ve lost them somewhere between “router” and “bandwidth.” Lean too far into “mitochondria are the powerhouse of the cell,” and students won’t see the bigger picture. But if you start throwing around terms like “electron transport chain,” you’ll lose them. (And it’s unnecessary at this level anyway.)
The trick is finding that sweet spot – enough depth for real understanding, but not so much that it feels like a crash course in biochemistry. Middle school is the perfect time to lay this foundation.
It’s important to note that I teach photosynthesis before I teach cellular respiration, and then I sort of cover them both together as a cycle. You can read about how I cover photosynthesis in this blog post HERE.
So please understand that the activities below are all done AFTER I’ve covered photosynthesis.
Even though I just threw a little bit of shade at boomers, I am still a little old school myself. When I teach cellular respiration in middle school, I like to start out by explicitly teaching the concept and then following up with inquiry activities, labs, and other stuff.
I start out teaching cellular respiration with a quick – but very effective – reading from my cellular energy reading set. The reading is not too hard, not too easy, but at just the right level. After students read about cellular respiration, they’ll analyze simple diagrams and answer follow-up questions. It’s a simple, straightforward way to introduce cellular respiration and gets everyone started on the same page.
A fun way to show cellular respiration in action is the bromothymol blue demonstration. It never fails to impress my students (even lately, when kids have generally been more apathetic!), and it takes less than 5 minutes of prep.
What You’ll Need:
Here’s What Works For Me: I set up a few containers of the bromothymol blue solution and let more than one student be the “demonstrator.” Fill your test tubes about 1/3 full with water and add a few drops of bromothymol blue until you get a nice blue color. Have a student gently blow through the straw into the solution (one straw per student for hygiene). The solution will gradually turn from blue to yellow as the CO2 from their breath forms carbonic acid. My students love watching the color change happen right before their eyes!
A fun way to make this activity “extra” (as the kids say) is to use a very long piece of tubing and have a student blow through the tubing to your cup of bromothymol blue solution on the opposite side of the room! Does it change the science? No. Is it just that much more fun? YES!
Pro Tips:
Bonus Discussion Point: Ask students why athletes breathe harder during exercise. This connects perfectly to this demo since more cellular respiration = more CO2 produced.
Don’t have bromothymol blue? You can show students this simple video!
While teachers appreciate my photosynthesis lab, kids LOVE my cellular respiration lab! Students watch as a balloon gets blown up by yeast performing cellular respiration!
This cellular respiration lab keeps it simple with clear and easy-to-follow instructions. Students add a few ingredients to a balloon and observe the changes over a class period. Students are amazed to see the changes to the balloon right before their eyes. But of course, there’s also rigorous questions to answer!
The laboratory materials are simple, cheap, and easy to obtain, but this is one of the most talked-about labs all year!
Now that my students have an understanding of both photosynthesis and respiration (remember, I cover photosynthesis first), I reinforce the learning with a sorting activity. It seems simple – and it is – but it is so effective to get kids to truly “get” how photosynthesis and respiration differ. It’s actually one of the most popular free downloads that I offer!
Students will sort and categorize 24 phrases that are associated with either photosynthesis or cellular respiration. Phrases review the reactants and products of each process, where they occur, how energy is involved, etc.
Try this simple activity to get kids thinking beyond memorized definitions!
Now that students have a solid background in photosynthesis and respiration, it’s time to highlight the connection between them and their cyclical nature.
I use these Cell Energy Stations as a fun way to get kids to explore and go deeper into photosynthesis and respiration without feeling overwhelmed or bored. Kids get up and moving around the room as they visit different stations and answer questions.
Some of the stations include a somewhat straightforward review of photosynthesis and respiration, while others go deeper into an interesting extension topic.
Stations Include:
It’s a great way to “pull everything together” at the end of a cell energy unit!
An awesome way to wrap up this unit is with a fun take-home project! This project supports a deeper understanding of the cyclical nature of carbon in photosynthesis and respiration, as well as how each process contributes to the cycle of matter in ecosystems.
While this assignment appears simple, the concepts are thoroughly based on NGSS science and are more complex than a simple food chain activity. Students are assigned to either make a diorama or a hanging mobile to represent the carbon cycle. They must represent every step carbon takes as it makes its way through the atmosphere, is in plants as carbohydrate, is released by burning fossil fuels, and more. Students must also include the reactants and products of photosynthesis and respiration.
So it’s more rigorous than it looks at first glance!
And kids love it!
Looking for a “done for you” option for teaching cellular respiration in middle school? Check out my complete photosynthesis and respiration unit. You’ll get EVERYTHING you need to teach these topics – from start to finish!
And don’t forget you can learn more about how I cover photosynthesis in this blog post HERE.
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