Heat and

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Chapter 13
 

• Heat and
• Temperature

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Chapter 13.1

• Temperature

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Objectives

• Define temperature in terms of the average
  kinetic energy of atoms or molecules.
• Convert temperature readings between the
  Fahrenheit, Celsius, and Kelvin scales.
• Recognize heat as a form of energy transfer.

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What is Temperature?
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Temperature

• Measures the average kinetic energy of all
  particles within an object
• As the KE the Temperature
• Kinetic Energy Energy of a moving object due to
  its motion

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Teacher Notes History of Temperature

• 1641, 1st sealed thermometer
• Used liquid rather than air as the thermometric
  medium
• Developed for Ferdinand II, Grand Duke of Tuscany
• His thermometer used a sealed alcohol-in-glass
  device, with 50 "degree" marks on its stem but no
  "fixed point" was used to zero the scale.
• These were referred to as "spirit" thermometers.
• 1724 that Gabriel Fahrenheit, an instrument maker
  of Däanzig and Amsterdam
• Used mercury as the thermometric liquid.
• 1745, Carolus Linnaeus of Upsula, Sweden
• Described a scale in which the freezing point of
  water zero, and the boiling point 100, making
  it a centigrade (one hundred steps) scale. Centi
  100 gradus degree in latin
• (1701-1744) used the reverse scale in which 100
  represented the freezing point and zero the
  boiling point of water, still, of course, with
  100 degrees between the two defining points.

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Continued History for Teacher

• 1933, the International Committee of Weights and
  Measures adopted a fixed point as the triple
  point of water
• Temperature at which water, ice, and water vapor
  coexist in equilibrium
• True Value is 273.16K
• Temperature unit on this scale is called the
  kelvin
• Lord Kelvin (William Thompson), 1824-1907, and
  its symbol is K (no degree symbol used).
• To convert from Celsius to Kelvin, add 273.

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How is the Temperature Taken?

• Thermometers
• Measures Temperature
• Temperature measurement
• Celsius
• Fahrenheit
• Kelvin

Quick Time Movie
9
Different Scales of Temperature
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Temperature Scales

• Fahrenheit
• Water
• Freezes at 32ºF
• Boils at 212ºF.
• Celsius
• Water
• Freezes at 0ºC
• Boils at 100ºC

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How do Thermometers Work?

• Physical Property
• Substances Expansion when HOT!!
• Contract COLD!!
• Thermometers alcohol or mercury
• Indicating temperature change

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Some other Types of Thermometers!!

• Digital Thermometers rely on current changes to
  detect temperature

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Other Thermometers

• Thermocouple Used to take high temperatures
• Electrons move up a wire due to being heated up
• Liquid Crystal (Kent State!!)
• Colors represent Temperature

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Scales of Temperature

• Fahrenheit
• Scale 32 F - 212 F
• Celsius
• 0 C 100 C
• Kelvin
• Based off Absolute Zero
• No Negative Numbers
• 273 K 373 K

Quick Time Movie
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What is Absolute Zero?
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Absolute Zero

• Lowest temperature there could ever be???
• Temperature
• at which particles
• no longer have
• kinetic energy to
• transfer

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Conversions in Temperature

• To Convert Temperature
• F (9/5)C 32.0
• C (5/9)(F - 32.0)
• K C 273

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Practice Problems

• The highest temperature ever recorded on earth
  was 57.8 C. Express this temperature both in
  degrees Fahrenheit and in Kelvin.
• 98.6 F is the temperature of the Body. What is
  the temp. in C and K?

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Temperature and Energy

• Heat Transfer of energy due to a difference in
  temperature.
• Feeling associated with a temperature difference
  results normally in an energy transfer!!

Quick Time Movie