# Chapter 14 Heat and Energy

## 29 terms · Vocabulary and concepts from Holt Science Spectrum Physical Science

### temperature

a measure of how hot (or cold) something is

### thermometer

an instrument that measures and indicates temperature

### absolute zero

the temperature at which molecular energy is at a minimum

### heat

the energy transferred between objects that are at different temperatures

### temperature

a measure of the average kinetic energy of the particles in an object

### absolute zero

0 degrees Kelvin or -273.15 degrees Celsius

### transfer

to carry or cause to pass from one thing to another

### thermal conduction

the transfer of energy as heat through a material

### convection

the movement of matter due to differences in density that are caused by temperature variations

### convection current

any movement of matter that results from differences in density; may be vertical, circular, or cyclical

the energy that is transferred as electromagnetic waves, such as visible light and infrared waves

### specific heat

the quantity of heat required to raise a unit mass of homogeneous material 1 K or 1 degree Celsius in a specified way given constant pressure and volume

### conduct

to be able to carry

### energy

specific heat x mass x temperature change

### entropy

a measure of the randomness of a system

### heat engine

a machine that transforms heat into mechanical energy, or work

### 1st Law of Thermodynamics

The total energy used in any process is conserved, whether that energy is transferred as a result of work, heat, or both.

### 2nd Law of Thermodynamics

The energy transferred as heat always moves from an object at a higher temperature to an object at a lower temperature

### mechanical processes

processes in which energy is transferred

### heat engine

a machine that converts chemical energy to mechanical energy through the process of combustion

### internal

taking place inside

### external

taking place outside

### carburetor

the part of an engine where gasoline is vaporized

### intake stroke

a mixture of fuel vapor and air is brought into the cylinder from the carburetor as the piston moves downward

### compression stroke

the piston moves up and compresses the fuel-air mixture

### power stroke

the spark plug ignites the mixture, which expands quickly and moves the piston down to turn the crankshaft

### exhaust stroke

takes place when the piston moves up again and forces the waste products to move out of the exhaust valve

### conductor

a material through which energy can be easily transferred

### insulator

a material that transfers energy poorly