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Chapter 10 Section 1
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Objectives:Describe how temperature relates to kinetic
energy
Compare temperatures on differenttemperature scales
Give examples of thermal expansion
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Its a Fact!How much energy does the human body radiate
in 1 second?
It radiates about as much energy as a 60 W lightbulb!
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Temperatur
e:Definition: a measure of the average kinetic
energy of the particles in an object
Temperature & Kinetic Energy:Matter is made of atoms and
molecules that are
constantly movingThe faster the particles move the more heat
they
create
http://www.humboldt.edu/~rap1/ChemSupp/Images/Trans_motion_Wiki.gif
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Average Kinetic Energy of
Particles:Individual particles have different amounts of
kinetic energy
Temperature is the measure of the averagekinetic energy
The temperature does not depend on howmuch of a substance you
have
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Measuring Temperature:Using a thermometer: a thin glass tube
filled with
a liquid
Mercury or alcohol often used because they remainliquid over a
large temperature range
Thermal expansion: the increase in the volume ofa substance
because of an increase intemperature
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3 Temperature Scales:Fahrenheit (F)Commonly used in the US
Celsius (C)Divided into 100 equal partsScientists frequently
use
Kelvin (K)Official SI temperature scaleO K or absolute zero
equal to about -459F
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Background on temperature
scales:Daniel Gabriel Fahrenheit (1686-1736):1st mercury
thermometer
He chose 30 as freezing temp of water and 90 as body temp
Anders Celsius (1701-1744):Used by the scientific community
He chose 0 as freezing temp and 100 as boiling temp of water
William Thomson (1824-1907) & Lord Kelvin:
Theorized that a substance would lose all energy at a temp of
-273CAssigned that point as zero on his scale
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Temperature Conversion:Fahrenheit (F) Celsius (C) Kelvin (K)
Water boils 212 100 373Body temp 98.6 37 310
Room temp 68 20 293
Water freezes 32 0 273
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Temperature Conversion:
EquationsTo Convert Equations (examples pg. 277)
Celsius to FahrenheitF = (9/5 x C) + 32
Fahrenheit to CelsiusC = 5/9 x (F -32)
Celsius to KelvinK = C + 273
Kelvin to Celsius C = K - 273
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Thermal Expansion:Expansion joints in highways
Bridges have expansion joints to protect againstbreaking in hot
weather
Bimetallic strips in thermostats2 different metals on a thin
strip
Expand at different rates
Coiling or uncoiling opens an electrical circuit
Thermal expansion in hot-air balloonsHeated air expands,
increase kinetic energy
Air becomes less dense than outside air, balloonrises!
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Quick Quiz:Most substances when they are
cooled.
Scientists use either the scale or the
scale.
Temperature as average kineticenergy decreases.
