Plants | Project Based Learning
In this 20-minute project-based chemistry lesson, students investigate how plant pigments relate to photosynthesis and why leaves change color. Working in small groups, they use simple observations and a quick comparison task to connect chemistry concepts to real plant materials.
| Term | Definition |
|---|---|
| Pigment | A colored substance in plants that absorbs some wavelengths of light and reflects others. |
| Chlorophyll | The green pigment in plants that helps capture light for photosynthesis. |
| Photosynthesis | The process plants use to make glucose from carbon dioxide and water using light energy. |
| Absorb | To take in light energy rather than reflect it. |
| Reflect | To bounce light back, which is why we see the color of an object. |
Show a green leaf and a red or purple plant image. Ask students why leaves are green and why some plants are red, purple, or yellow.
Observe the samples and give quick verbal predictions.
Explain that plants contain pigments that absorb and reflect different wavelengths of light. Briefly connect chlorophyll to photosynthesis and mention that other pigments can become more visible when chlorophyll breaks down.
Listen, take brief notes, and answer one or two quick questions.
Place students in pairs or small groups. Give each group leaves or plant images and a short sorting prompt: identify the pigment color seen and predict its role or meaning for the plant. Circulate and support reasoning.
Sort observations on the handout, discuss as a group, and write one evidence-based claim about plant pigments.
Invite two or three groups to share one claim. Confirm accurate connections between pigment color, light absorption, and photosynthesis.
Share one result and compare ideas with classmates.
Ask students to complete a one-sentence exit response: 'A plant pigment helps because...'
Write and submit an exit response.
Reinforce that plant color comes from pigments, and pigments matter because they help plants manage light energy. Remind students that chlorophyll is central to photosynthesis, while other pigments can affect how plants appear.
Formative assessment will be based on group discussion, the evidence-based claim on the handout, and the exit response at the end of class.
Find one plant at home or online that is not green. Write 3-4 sentences explaining what pigment colors it may contain and how those colors might relate to light absorption or plant function.