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Teaching photosynthesis can be daunting. How much do I teach? How can I make photosynthesis simple without dumbing it down and leaving out important structures and steps?
After trying many strategies for a few decades, I got it right, these last few years. My students moved through the process steadily with (relatively little) stress. They nailed their unit test with the help of our summarization strategies, and blew our EOC test scores out of the state.
Best of all, they learned. They asked questions as we were working together and shared their learning with one another. They affirmed that if given the chance, students learn best from one another. Over the years, I’ve fleshed out the details dritical to student understanding and found effective strategies for presenting that content
Here’s how you can do it, too.
Start with an activity that introduces photosynthesis from the perspective of Jean Baptiste von Helmont, who wondered whether the mass of a plant came from the soil in which the plant lives or from the water taken up. (Turns out, neither, but that’s what your students will find out.)
Take von Helmont’s experiment further with a demo that shows that air really is made of stuff. There’s a 1-page reading – first a bit of history on the experiment, then von Helmont’s own writing about his experiment Students first do a science-modified close read to identify an experimental question, evidence, and a claim; well, as much can be identified in writing that took place before we had any type of scientific methodology.
Then, move on to a demo examining what happens when a beaker is placed over the top of a burning candle in a pan of water. Directions for this demo are in the resources in the link at the bottom of this page. A brief video is below, in case your students are online, or absent for the video.
To further investigate atmospheric gases and their effects on plants and animals, Joseph Priestly set up 3 trials. The mouse and the plant both lived longer when they were together. Interesting.
Soon after LaVosier’s work, Inglehaus (17790 took the investigations a step further, with evidence that sunlight was necessary for this symbiotic relationship.
Discuss this with students. Ask them to write in their understanding in their guided notes and talk with a partner. Or two partners. Let them talk. Listen to them.
Partner talk and listening is important as you move though the content in the photosynthesis steps.
The next activity involves students learning the important structure of a leaf, from the layers of cells down to the chlorophyll on a thylakoid.
Once students are comfortable with the structures, I break the process down into light dependent reactions and light independent reactions Since state standards (in most states and the NGSS) focus on the process rather than details such as names of enzymes and the electron transport chain, I don’t focus on them either We DO focus on inputs and outputs and where in photosynthesis they occur. We also count the carbons and follow the flow of energy from the sun to the sugars produced.
You can work through these scenarios and activities with your own slides, or you can get mine at this link: Photosynthesis slides, guided notes, and lab.