1. Light energy: Plants absorb light energy from the sun using chlorophyll, a green pigment.

2. Water splitting: This light energy is used to split water molecules (H₂O) into hydrogen ions (H+) and oxygen (O₂). The oxygen is released into the atmosphere.

3. Carbon fixation: The hydrogen ions and energy from the light are used to convert carbon dioxide (CO₂) into glucose (C₆H₁₂O₆), a simple sugar. This process is called carbon fixation.

So, in essence, plants don't just split carbon dioxide molecules, they use the carbon from those molecules to build glucose, which is their food source. This process is crucial for the survival of plants and forms the basis of the food chain.