6.1: Thermal
Energy,
Temperature, and
Heat
PHYSICAL SCIENCE
Essential Questions:
How are temperature and kinetic energy related?
How do heat and thermal energy differ?
Total RECALL
RECALL: the energy of motion is referred to as kinetic energy
RECALL: potential energy is stored energy
RECALL: mechanical energy is a combination of both kinetic and potential
RECALL: all matter is made of particles
What we will see is that these particles have both kinetic and potential
energy and therefor a type of mechanical energy
◦ We refer to this type of mechanical energy as thermal energy
Thermal Energy
The sum of the kinetic energy and the potential energy of the particles
that make up a material
Depends on three things
◦ The number of particles in the object
◦ The temperature of the object
◦ The arrangement of the object’s particles
Thermal Energy
Temperature
RECALL: all matter is made of tiny
particles that are always in motion
RECALL: the energy of motion is
kinetic energy
Temperature is a measure of the
average kinetic energy of the
individual particles in matter
◦ The greater the average kinetic
energy, the greater the
temperature
Relating Temperature to
Thermal Energy
These two concepts are related
but are NOT the same thing
It all comes down to distance
◦ Ex: a melting pond
◦ Both the ice and the water have the same
temperature
◦ In the such, they have the same kinetic
energies
◦ As the ice melts, the distance between the
particles increases, therefore increasing
potential energy
Measuring Temperature
We use thermometers to measure temperature
◦ These usually consist of a liquid sealed inside a narrow class tube
◦ When the tube is heated, the particles of the liquid speed up and spread out
◦ When the tube is cooled, the particles of the liquid slow down and move closer
Temperature Scales
There are three common scaled for measuring temperature:
◦ The Fahrenheit
◦ Celsius
◦ Kelvin
Each scaled is divided into regular intervals
Fahrenheit Scale
Commonly used in the U.S.
Notable temperatures on this
scale:
◦ Freezing point of water: 32°F
◦ Boiling point of water: 212°F
◦ “Normal” body temperature:
98.6°F
Celsius Scale
Common in nearly all other
countries
Degrees Celsius are larger units
than degrees Fahrenheit
Notable temperatures:
◦ Freezing point of water: 0°C
◦ Boiling point of water: 100°C
Kelvin Scale
Commonly used in physical science
Units are the same as on the
Celsius scale
Notable temperatures:
◦ Freezing point of water: 273 K
◦ Boiling point of water: 373 K
◦ Absolute zero: 0 K
◦ Coldest temperature possible
◦ Equals -273°C
Converting Between Scales
Converting from degrees Fahrenheit to degrees Celsius
◦ °C = 5/9(°F – 32)
Converting from degrees Celsius to degrees Fahrenheit
◦ °F = 9/5(°C) + 32
Converting from degrees Celsius to Kelvin
◦ K = °C + 273
Thermal Energy and Heat
Different objects at the same temperature can have different energies
Thermal energy IS NOT heat
◦ Temperature, thermal energy, and heat are closely related, BUT they are all
different
Heat
This is thermal energy that is
transferred from matter at a
higher temperature to matter at a
lower temperature
◦ In other words…
◦ Heat is thermal energy moving from a
warmer object to a cooler object
RECALL: work also involves the
transfer of energy
◦ Because work and heat are both
energy transfers, they are both
measure in joules
Essential Questions Answered:
How are temperature and kinetic energy related?
◦ The temperature of a material is the average kinetic energy of the particles
that make up the material.
How do heat and thermal energy differ?
◦ Heat is the movement of thermal energy from a warmer material to a cooler
one
For Next Time:
Reading:
◦ Pg. 204-212
Homework:
◦ 6.1 Study Guide
◦ Temperature Conversion Worksheet