Here's how it works:

1. Photosynthetic organisms, like plants, algae, and some bacteria, use chlorophyll (a green pigment) to capture light energy from the sun.

2. This energy is used to split water molecules (H₂O) into hydrogen (H) and oxygen (O₂) .

3. The oxygen is released into the atmosphere as a byproduct.

4. The hydrogen is combined with carbon dioxide (CO₂) to create glucose (sugar), which the organism uses for energy.

In summary: Photosynthesis uses light energy to split water molecules, releasing oxygen into the atmosphere.

Here's a simplified equation for photosynthesis:

Sunlight + CO₂ + H₂O → C₆H₁₂O₆ + O₂

This process is essential for life on Earth as it provides the oxygen that most organisms need to breathe.