Yes, you can teach photosynthesis so kids understand it. Keep it macro! First, roots pull in water. Second, leaves take in carbon dioxide. Then energy from the Sun causes a chemical reaction, and glucose is formed. A variety of fourth and fifth grade science standards support conceptualization of this important process.
Mr. Grow Prepares to Teach Photosynthesis
Our favorite fourth grade teacher, Ms. Sneed sat at the side table with her former student teacher. “As you prepare to teach fifth grade,” she said to Mr. Grow, “it’s important to understand the role of photosynthesis in life science standards. It’s all about making connections.”
Begin with Plant Structures and Functions
Ms. Sneed opened her laptop. Then she positioned it so Mr. Grow could see. “If you remember, fourth grade students explore plant structures and functions.” She pointed to the plant unit on the screen.
“Right. Roots take in water and stems transport it. In my class, kids explored plant parts with hands-on activities. And actually, we did touch on photosynthesis a bit. That function occurred in leaves.”
“Exactly. And if you think about it, most plant structures support one key process: photosynthesis.”
Mr. Grow wrinkled his brow. “Hmm, I never thought of that.” Then he smiled. “I guess that’s an important point to make with my students.”
Ms. Sneed nodded. “Yep. You’ve made your first curricular connection. For those of us teaching the Next Generation Science, these activities support NGSS 4-LS1-1.”
Use Hydroponics to Show That Photosynthesis Only Requires Air and Water
Ms. Sneed clicked away on her device. Soon, a hydroponics unit appeared on the screen. “In fifth grade,” she said, “you’ll teach NGSS 5-LS1-1. To address it, kids need to ‘support an argument that plants get the materials they need for growth chiefly from air and water.’ Basically, it boils down to hydroponics. I’m sure your students will enjoy these activities.
“First, kids germinate seeds in baggies. Then they take it a little farther with a hydroponics STEM challenge.”
Mr. Grow scratched his head. “I get it,” he said. “More photosynthesis. Obviously, air and water are the ingredients needed for photosynthesis.”
The mentor teacher’s eyes twinkled. “Right,” and as the teacher, you will help kids make the connections.”
Remember, Photosynthesis Is a Chemical Change
Next, she opened a matter unit. “Here,” she explained, “chemistry meets biology. The connection, however, is not so obvious. As your kids move through these physical science activities, they’ll learn all about matter. For NGSS 5-PS1-4, they develop particle models. Then, for 5-PS1-2, they explore all kinds of changes, as well as conservation of mass. In NGSS 5-PS1-3, they explore properties of matter.
“But the most important link to photosynthesis is NGSS 5-PS1-4: ‘Conduct an investigation to determine whether the mixing of two or more substances results in new substances.'”
“Ahh, chemical change.”
“Right. Clearly, you should teach matter before photosynthesis. That way, you can make connections.”
“Because photosynthesis is a chemical change.”
Ms. Sneed nodded in agreement.
Photosynthesis Is Necessary Part of the Food Chain
“Next, let’s talk about energy. In fourth grade, kids spend lots of time on forms of energy. Most of their exploration, however, focuses on kinetic energy.”
“I remember,” said Mr. Grow. “Sound, light, heat, and electricity.”
“Yes, and also motion.”
Mr. Grow nodded but looked a little puzzled. He wasn’t sure where she was going with this.
“In fifth grade,” his mentor continued, “you’ll teach potential energy. Specifically, the chemical energy stored in plants.”
The mentee’s face brightened. Then he shook his head. “Never in a million years,” he said, “would I have made that connection. You’re giving me such great ideas for reviewing fourth grade standards. Not only that, I can actually connect prior learning to fifth grade concepts.”
Ms. Sneed chuckled. “Yup. That’s the idea.”
On the laptop, she now opened a food chain resource. “For NGSS 5-PS3-1, kids must describe how energy for animals’ food originally came from the Sun.”
Mr. Grow pointed to the screen. “I see. Knowledge of photosynthesis helps kids understand food chains.”
“Right again. First, students explore producers, consumers, and decomposers. But ultimately, they will explain how the energy flows from the Sun to plants to animals.”
Energy from the Sun Moves Through Ecosystems
After a little more searching, Ms. Sneed pulled up an ecosystems unit. “This set of resources teaches NGSS 5-LS2-1. While it deals with the movement of matter, you can also make connections here. Not only does photosynthesis power individual food chains, it also flows through entire ecosystems.”
Ms. Sneed referred to her standards document. “Additionally, photosynthesis plays a big part in interactions between Earth’s spheres. Kids need to understand it for NGSS 5-ESS2-1. First, water from the hydrosphere enters a plant through its roots. Simultaneously, carbon dioxide from the atmosphere enters leaves. Then, through a chemical reaction, energy from the Sun converts them to glucose. Voila! Food for the entire biosphere is formed.”
In Fourth and Fifth Grades, the Cellular Level Is Optional
Mr. Grow sat back in his chair. “What about cells?” he asked.
“Well, that’s a tough one. While the standards don’t address the cellular level until middle school, I still like to introduce them. Nothing elaborate, though. As a matter of fact, we do only a tiny bit of microscope work and an introduction to organelles.”
“Yeah, a little knowledge of chloroplasts makes one more connection. But I’ll consider cells to be optional.”
Connections = Effective Teaching
“Let’s review,” said Ms. Sneed.
- In fourth grade, we teach kids about plant structures. Basically, all functions directly support photosynthesis.
- In fifth grade, understanding that plants mainly need air and water reinforces that.
- Then kids learn about chemical changes. And what’s the most important chemical change?
- Furthermore, fourth grade standards focus on transfer of energy. Then in fifth, you’ll teach them how the Sun transfers light energy to plants. And ultimately, that energy fuels all life in every ecosystem.”
“Wow,” said Mr. Grow, “as a new teacher, I never would have made all of these connections. This background information will allow me to teach so much more effectively.”