Principles of Heat Crossword Puzzle

QUESTIONS LIST: conduction: when heat travels through a solid material, convection: when heat travels through a liquid or gas, radiation: when heat travels via infrared light, kelvin: the scientific unit for measuring heat, insulation: used to prevent the ingress of cold or to prevent the loss of heat, fuel: one of the items needed for combustion, oxygen: part of the fire triangle, needed for combustion, natural: _ _ _ _ _ _ _ - gas, commonly used in domestic properties for boiler and cooker fuel, propane: a gas commonly used in blowlamps