Means of communication refer to the methods and systems used to transmit information from a source to a recipient. Fundamentally, these means involve the transfer of signals, which can manifest as electromagnetic waves, mechanical vibrations, or chemical signals. From a physical science perspective, communication relies on the properties of mediums, such as the vacuum of space or conductive materials, to propagate energy. Technologies range from audible mechanical signals to complex, encoded radio frequencies. The efficiency and bandwidth of a communication system are dictated by the physical laws governing signal decay, interference, and the method of encoding the transmitted data.