
Describe the image 
◦ What is it?
◦ What does it measure?
◦ How does it work?

What is it?
◦ Scalar
◦ Provides information about how hot or cold
something is

Measured with a Thermometer
◦ Temperature noted on the thermometer is equal to
that of the object when the two are in equilibrium
◦ How do thermometers work?


Physical properties of matter can change
dependent on temperature
Thermometers follow 1 of the principles
◦
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Thermal Expansion of a liquid
Electrical Resistance of a wire
Pressure of a gas (in a fixed volume)
Linear Expansion of Solids
Color of a solid heated to high temperatures
How would you make a thermometer?

Fahrenheit (1724)
◦ Salt:water:ice mixture and body temperature

Celsius (1742)
TC = (5/9) (TF - 32)
Kelvin (1848)
TK = TC + 273.15
◦ Freezing and boiling point of water

◦ Gas Expansion Coefficient and Celsius
◦ Fundamental unit for temperature
◦ At 0 K, all molecules stop moving (theoretically)
 Freezes:
32° F = 0° C = 273.15 K
 Boils: 212° F = 100° C = 373.15 K
 At
standard pressure!
 1 atm
 760 mm Hg (Torr)
 101,325 Pa = 101.325 kPa
 1.01325 bar
Critical Point
–
Triple Point
–
Above this point,
the liquid phase and
gas phase merge
into 1 phase, a
supercritical fluid
Water, Ice, and
Steam exist

For Gases: EK = (3/2)k*T
◦ EK  Kinetic Energy
◦ T  Temperature
◦ k  Boltzmann Constant
 k = 1.38 x 10-23 JK-1

Distribution of
KE values

Internal E = PE + KE of all particles within the
system

Potential Energy

Kinetic Energy - movement
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◦ Bond Energy – energy stored in bonds
◦ Intermolecular forces – attractive energy between particles
◦ Translational - straight line
◦ Rotational – spinning about an axis
◦ Vibrational – back and forth motion centered at a point
Solids – mainly vibrational
Liquids – mainly vibrational, some rotational, little
translational
Gases – Mainly translational and rotational

Conduction – Physical contact hot  cold

Convection – movement of fluids cold  hot
◦ Particle collisions – no net movement
◦ Gases – slow; Liquids – medium; solids – fast (metals)
slow (generally non-metals)
◦ Only fluids
◦ Density differences in fluids
 Hot – more energy, further apart, lower density
 Cold – less energy, closer together, higher density

Radiation – light is released and absorbed
◦ No matter necessary for transfer
◦ EX: SUN

Heat – energy that is transferred due to

Temperature – measure of AVG. kinetic

Internal Energy – total kinetic energy and
temperature differences
energy of the molecules in a substance
potential energy associated with forces and
bonds among the molecules in a substance.