Teaching leaves and photosynthesis in fourth and fifth grades can be tricky. Just take it slow and easy. First, teach the basics of cells and chemical reactions. Then move on to leaf parts. Soon kids will be ready for an introduction to the process.
Ms. Sneed Prepares for Teaching Leaves and Photosynthesis
After school, our favorite fourth grade teacher sat at the side table. “Next in life science,” she said to her teaching partner, “we’ll teach kids about leaves and photosynthesis.”
“Ah,” said Mr. Frank, “the last of our plant structures and functions.”
“Right. First, we tackled seeds and germination. Second, kids explored flowers and pollination. As you know, in our third mini-unit, they simulated roots and stems. Fortunately, those seemed pretty easy. But I’m worried about this next topic. It requires some heavy-duty background knowledge.”
“Agreed. To understand photosynthesis, kids need to know a little about cells. Especially chloroplasts. Furthermore, a little tutorial on chemical change wouldn’t help.”
Ms. Sneed shuddered. “A little deep for fourth grade, but let’s do it. Integrating science ideas will help them understand.”
She opened her laptop and started clicking away.
Leaves Have Chloroplasts for Photosynthesis
“Here we go,” Ms. Sneed said. “We can do a one-day lab on plant and animal cells.”
“Wait, does this mean we get to break out the microscopes?” Mr. Frank grinned.
“Sure does! After reading a little about cells, kids can look at cheek and onion cells under a microscope. That will establish that plant leaves have chloroplasts.”
“And that will provide one critical piece of background knowledge for teaching photosynthesis. Great!”
In a Chemical Change, a New Substance Is Formed
Ms. Sneed sighed. “Next up, chemical change. Seriously, I don’t want to make a big production about this. After all, it’s a fifth grade concept.”
“Then we can just stick to the basics. In physical change, the object is altered or mixed in some way, but no new substance is formed. However, during a chemical change, the particles rearrange, and a new substance is formed.”
“Right.” Ms. Sneed pulled up a page physical and chemical changes. “What do you think about a simple introduction like this?”
“Yes, I think that would work. Of course, we could always throw in just a little investigation. I think I’ll use the tried-and-true baking soda and vinegar activity.”
“Perfect,” said Ms. Sneed.
The Main Function of Leaves Is Photosynthesis
Next, the teacher pulled up a few pages on photosynthesis. “What do you think of these?” she asked.
“Hmm. I think the pictorial approach is right for fourth grade. It shows that roots pull in water and leaves take in carbon dioxide. Chlorophyll absorbs the sun’s energy, and voila! A chemical reaction changes the water and carbon dioxide to glucose. In the process, oxygen is released. That’s all they need to know.”
“I like the other page too. But not necessarily for our kids. For us. It offers some great background information – and will help us answer questions.”
Parts of Leaves Facilitate Photosynthesis
“Now that they know about photosynthesis,” said Mr. Frank, “I suppose it’s time to teach anatomy of leaves.”
Once again, Ms. Sneed pecked around on her computer. “Here,” she finally said. “First, we can go over these leaf parts and their functions. Then kids can do this worksheet.”
“Wow,” Mr. Frank exclaimed. “This is super thorough. But I agree that it will work for our students. It definitely supports our standard on plant and animal structures. Furthermore, it provides background needed for the fifth grade standards on hydroponics.”
Photosynthesis Occurs When Particles Rearrange
Ms. Sneed sat back in her chair. “Look.” She pointed to the screen of her laptop. “In this activity, students rearrange atoms to simulate photosynthesis. Do you think it’s too sophisticated for our kids?”
Mr. Frank’s eyes glowed. “Ha! You know how I feel about stuff like this. Yes, I feel that they will be ready. Although we aren’t teaching this much chemistry in fourth grade, it will give them a great preview.”
“And help build conceptual understanding,” Ms. Sneed added.
“Let’s go over the activity. Before the lab, we gather items for them to use. First, we’ll need twelve small objects to represent hydrogen. In this picture, they used raisins. Second, we’ll need eighteen medium-sized pieces for oxygen. Here, they used M&Ms. Third, we’ll gather six larger items, like the candy they used.”
“Um-hm. The first page of the activity asks kids to create six water molecules on the top of the page. Then, on the bottom of the page, they create six carbon dioxide molecules. All of the pieces will be used up in these two sections.”
Ms. Sneed scrolled to the next page. “On this page, kids rearrange the pieces. First, they use most of the pieces to build a glucose molecule. And the pieces that are left over are paired and released. Again, all atoms are used.”
“Sounds like the law of conservation of mass to me,” Mr. Frank chuckled.
“Haha. Let’s not get ahead of ourselves. I stand with your earlier comment. For me, this will provide a quick preview to much more sophisticated chemistry concepts in kids’ futures. But I don’t even want to bring up any of the lingo.”
Mr. Frank nodded reluctantly. “As much as I’d love to dig into it, I agree.”
Then he chuckled. “Okay, I admit it. Even digging into these concepts a little makes me enjoy teaching. When we put together challenging units, I simply love it. This leaves and photosynthesis sequence will be great.