What unit of heat is required to raise one pound of water by one degree Fahrenheit?

The unit of heat required to raise one pound of water by one degree Fahrenheit is known as a British thermal unit (BTU). Specifically, one BTU is defined as the amount of heat needed to raise the temperature of one pound of water by one degree Fahrenheit at a constant pressure. This makes it a key unit in thermodynamics and engineering, especially in the context of heat transfer and energy calculations.

The other units mentioned, such as the joule and calorie, are used for measuring heat as well, but they relate to different quantities. The joule is part of the International System of Units (SI) and is a smaller unit of energy, whereas the calorie is defined as the amount of heat required to raise the temperature of one gram of water by one degree Celsius—making it a different context than that of the BTU. The newton is a unit of force, not heat, and thus is not applicable in this context. Therefore, the British thermal unit is the appropriate choice when discussing the specific heat requirement for water in imperial units.