Heat is the transfer of thermal energy between objects due to a temperature difference. It can occur through conduction, convection, or radiation. Conduction involves the transfer of kinetic energy between adjacent particles in direct contact. Convection involves the combined effects of conduction and fluid motion. Radiation is the emission and transmission of electromagnetic waves. Fourier's law and Newton's law of cooling quantitatively describe the rates of heat transfer through conduction and convection. Wien's law and Stefan-Boltzmann law govern the wavelength and power of thermal radiation from a black body.