When a hamburger sizzles on a frying pan is that radiation?

No, the sizzling of a hamburger on a frying pan is not radiation; it is primarily a result of conduction and convection. The heat from the frying pan cooks the hamburger through direct contact (conduction), while the hot air around it helps distribute heat (convection). Radiation, in this context, refers to the transfer of heat through electromagnetic waves, which is not the primary mechanism at play in this cooking process.