Photosynthesis
Explain photosynthesis as the process by which plants use light energy to convert carbon dioxide and water into glucose and oxygen, and describe how mineral nutrients are absorbed through roots
What a learner can do afterwards
- Writes and explains the word equation for photosynthesis
- Identifies the raw materials needed and the products made
- Explains the role of chlorophyll in capturing light energy
- Distinguishes between what plants get from the air (CO₂), soil (water and minerals), and light
The lesson
You already know plants need light, water, and air to grow. Photosynthesis is the process that turns those things into food. Inside a leaf, a plant combines carbon dioxide from the air with water from the soil. Using light energy, it turns them into a sugar called glucose, plus oxygen as a byproduct.
Picture a tomato plant on a sunny windowsill. Its roots pull up water and dissolved minerals from the soil. Its leaves take in carbon dioxide through tiny holes. Inside the leaves, chlorophyll, a green pigment packed into chloroplasts, captures sunlight and uses that energy to join the carbon dioxide and water into glucose. The plant releases oxygen as it works.
Keep the three sources straight: air gives carbon dioxide, soil gives water and minerals through the roots, and the sun gives light energy. Remember the deep-sea creatures you learned about that live in total darkness? Plants are the opposite. Without light, photosynthesis cannot happen at all.
Photosynthesis uses light energy, captured by chlorophyll, to turn carbon dioxide and water into glucose and oxygen, while roots separately absorb water and minerals from the soil.
Watch it
Where it sits
Where this leads
Jobs that lean on this skill. Follow one to see everything it is built on.
8 questions wait behind this lesson, each with its answer explained. Every answer feeds the sky: stars light as they are learned, and dim when it is time to come back.