Introduction to Energy Forms, Units, and Heat Transfer

A set of vocabulary flashcards defining key energy units, forms of energy, thermo physical laws, nuclear processes, and heat transfer mechanisms based on Chapter 1 through Chapter 6 of the lecture.

Joule

The SI base unit for energy, defined as one Newton meter ($1\text{ N}\text{m}$) or one kilogram meter squared per second squared ($1\text{ kg}\text{m}^2/\text{s}^2$).

Calorie

The base unit of heat needed to raise the temperature of one gram of water by one degree Celsius ($1\text{ }^\text{o}\text{C}$), equal to $4.184\text{ joules}$.

Kilocalorie

A unit equal to one thousand base calories, commonly used in the food industry to represent the chemical energy released when food is consumed.

Kilowatt hour

A unit of energy frequently used in the power sector to measure electricity consumption rates on utility bills.

Potential energy

The energy an object possesses based on its mass, elevation from a datum (ground level), and potential to go into motion, calculated as $PE = mgh$.

Kinetic energy

The energy associated with the motion of an object, calculated using the equation $KE = \frac{1}{2}mv^2$.

Mechanical energy

A form of energy comprising the combined total of potential energy and kinetic energy in a system.

First law of thermodynamics

The physical principle stating that energy cannot be created or destroyed, only changed from one form to another.

Chemical energy

Energy stored within the chemical bonds holding molecules together, which is released through combustion or chemical reactions.

Nuclear energy

Energy intrinsic to the nucleus of a single atom, defined mathematically by Einstein's equation $E = mc^2$.

Nuclear fission

A process where a single nucleus spontaneously decays or splits into two smaller nuclei, releasing energy.

Nuclear fusion

A process where two smaller nuclei join together to form a larger nucleus, releasing a substantial magnitude of energy and heat.

Radiant energy

A form of energy transmitted via electromagnetic light rays, such as visible light from a bulb or solar energy filtered by solar panels.

Thermal energy

Also known as heat, this kinetic energy form is caused by colliding molecules, measured by temperature, and naturally moves from higher to lower temperatures.

Rejected energy

Energy lost from a non-ideal system, primarily as waste heat due to frictional losses; accounts for roughly 66\text{ }\text{\textpercent} to 67\text{ }\text{\textpercent} of primary energy consumed on the power grid.

Conduction

The transfer of heat directly through a physical medium, such as a solid metal object.

Convection

The transfer of heat caused by the bulk movement of a fluid, such as air driven by a fan or ocean water currents.

Radiation (heat transfer)

The transfer of heat through electromagnetic waves, such as heat delivered from the sun to the Earth.