The transparency of glass is due to its chemical structure, allowing photons to pass through with minimal distortion. Heat transfer from a gas burner to water occurs through the glass, which is in direct contact with the burner but not with the water. Convection currents can occur in liquids and gases, but not in solid materials like glass, where molecules only vibrate in place. The discussion clarifies that while convection transfers thermal energy in water, it does not occur within the glass itself. Thus, the heat transfer mechanism through the glass is distinct from convection processes in the water.