Here's how it works:

* Light energy is absorbed by chlorophyll, a pigment found in chloroplasts within plant cells.

* This light energy is used to split water molecules (H₂O) into hydrogen ions (H⁺), electrons (e⁻), and oxygen (O₂).

* The electrons are passed through a series of electron carriers, releasing energy that is used to convert carbon dioxide (CO₂) into sugar (glucose).

* The oxygen is released as a byproduct.

So, while light isn't a chemical itself, it's the essential energy source that drives the chemical reactions of photosynthesis.