### How plants use sunlight to make food (photosynthesis)

- **Big idea**: Plants turn sunlight, water, and carbon dioxide into sugar (their food) and oxygen. It’s like having tiny solar-powered kitchens in their leaves.

- **Sunlight capture**: Leaves act like solar panels. Inside them are chloroplasts with green chlorophyll that absorbs light energy.

- **Raw materials**:
  - **Water (H2O)**: Pulled up from the soil by roots.
  - **Carbon dioxide (CO2)**: Enters leaves through tiny pores called stomata.

- **Two main stages**:
  - **Light reactions** (need sunlight): Light energy splits water, releasing oxygen (O2) and making energy carriers.
  - **Sugar-building stage** (Calvin cycle): Uses those energy carriers to stitch CO2 into glucose (a sugar).

- **Products**:
  - **Glucose (C6H12O6)**: Fuel and building material for growth; extra is stored as starch.
  - **Oxygen (O2)**: Released into the air—what we breathe.

- **Simple equation**: \(6\text{CO}_2 + 6\text{H}_2\text{O} + \text{light energy} \rightarrow \text{C}_6\text{H}_{12}\text{O}_6 + 6\text{O}_2\)

- **Why it matters**: Photosynthesis feeds plants, which feed almost everything else, and it keeps Earth’s air full of oxygen.