No, a fire cannot burn in water. Fire requires three elements to sustain: fuel, oxygen, and heat. While water does contain oxygen molecules (H₂O), they are chemically bonded to hydrogen atoms and not available for combustion.
When a fire burns, it typically involves the reaction of a fuel source (such as wood, paper, or gasoline) with oxygen from the air, resulting in the release of heat, light, and combustion byproducts. Water, on the other hand, is primarily composed of hydrogen and oxygen bonded together in a stable molecular structure. The strong bonds between hydrogen and oxygen make it difficult for water molecules to break apart and release oxygen for combustion.
If you were to introduce a combustible material into water, such as oil or a flammable liquid, the water would act as a barrier to prevent the oxygen in the air from reaching the fuel and sustaining a fire. The heat required for combustion is typically dissipated by water, further inhibiting the ability of a fire to burn.
However, it's worth noting that certain substances can undergo a chemical reaction with water and release flammable gases. In such cases, the flammable gases produced above the water surface could potentially burn if ignited. But the fire would not be burning "in" the water itself.