Photosynthesis can be a difficult concept for some children to understand. They are familiar with plants and plant parts as well as what helps a plant to grow. But the concept of the plant making its own food is new to them, and it often takes several lessons to understand photosynthesis fully.
Build on Prior Knowledge
Teaching photosynthesis should start with a review of plant parts and what plants need to grow. Most students will have some prior knowledge of both of these concepts. They may not remember what each plant part does or everything a plant needs to grow, but they should be able to label parts such as leaves, roots, and the stem, and remember that a plant needs sunlight, soil, water, and carbon dioxide (or air) to grow. You can even start this lesson by planting a flower in a pot (or individual seeds in styrofoam cups) in your classroom and talking about the plant parts and plant needs while doing the activity.
Once this has been reviewed, you are reading to move on to the second part of teaching photosynthesis.
Discuss Process and Vocabulary
Once children have planted something and have reviewed their prior knowledge, now you want to introduce the term photosynthesis. Write this term on the board or chart paper and have children practice saying it. You might even want to clap out each syllable--to reach all styles of learning.
It's also best to have a diagram of photosynthesis to display in your classroom. You can use one from the Internet, or you can create your own that better matches your objectives. Display the diagram and have a real plant on display while teaching students the process. When teaching photosynthesis, remind students that plants need water, air (carbon dioxide), and sunlight because it mixes with the cholrophyll in the leaves to produce food. Explain how the green color of the leaves comes from the cholorophyll. You will also want to teach students how the process gives off oxygen for us to breathe and how the food is carried to the rest of the plant. A diagram will help visual learners while orally explaining the process will help auditory learners.
Activities and worksheets
When you are finished teaching photosynthesis, you will need to provide guided and individual practice. Once students have reviewed prior knowledge and learned about the photosynthesis process, you can do several activities or assign worksheets to students, so they will learn the process and the vocabulary. Here are some ideas:
- Play a quiz game with students where all the questions focus on photosynthesis. Divide students into two teams. Reward one point for each correct answer a team gives. You can also do a "race" for the correct answer. The first team that answers correctly receives two points. Any correct answer receives one point.
- Give students their own individual photosynthesis diagram to label. Once you have checked their labeling, students can save these in their science folders to refer to when they have a question about photosynthesis.
- Students can do a teaching photosynthesis lesson for each other. For example, one student takes a diagram and explains to a partner how a plant makes food. The other student can ask questions that the "teacher" has to answer. They can switch roles to give the other student a chance to teach it.
Teaching photosynthesis does not have to be difficult if you use some of these teaching methods and ideas.