13-1: Temperature
Monday, January 04, 2016
7:35 AM
Key Terms:
1. Temperature - a measure of how hot (or cold) something is; specifically, a measure of the average
kinetic energy of the particles in an object.
2. Thermometer - an instrument that measures and indicates temperature
3. Absolute zero - the temperature at which molecular energy is at a minimum (0 K) on the Kelvin scale
or -273.16⁰C (on the Celsius scale)
4. Heat - the energy transferred between objects that at different temperatures
1. In drawing 1, which bowl would feel warm to your hands? Which bowl would feel cool?
2. In drawing 2, which bowl would feel warm to your hands? Which would feel cool?
3.
A person from Seattle tells his friend from Florida that the weather in Seattle is somewhat warm.
When the friend arrives for a visit, he finds that he is uncomfortably cool wearing the shorts he
packed. What would be a more effective way for the person from Seattle to explain the weather?
I. Temperature and Energy
• Temperature is a measure of how hot (or cold) something is.
Ch13 Heat and Temperature Page 1
• Temperature is a measure of how hot (or cold) something is.
• Specifically, it is a measure of the average kinetic energy of the particles in an object. As the average
kinetic energy of an object increases, its temperature will increase.
• A thermometer is an instrument that measures and indicates
temperature.
• Fahrenheit and Celsius are common scales used for measuring
temperatures.
• On the Fahrenheit scale, water freezes at 32ºF and boils at
212ºF.
• The Celsius scale, which is widely used in science, gives a value
of 0ºC to the freezing point of water and a value of 100ºC to the boiling point of water at
standard atmospheric pressure.
Fahrenheit-Celsius Conversion Equations
A degree Celsius is 1.8 times as large as a degree Fahrenheit. Also, the temperature at which water
freezes differs for the two scales by 32 degrees.
TF = Fahrenheit temperature
t = Celsius temperature
The Kelvin scale is based on absolute zero.
Absolute zero is the temperature at which molecular energy is at a minimum (0 K on the Kelvin scale
or –273.16ºC on the Celsius scale).
Celsius-Kelvin Conversion Equation
T = t + 273
T = Kelvin temperature
t = Celsius temperature
Ch13 Heat and Temperature Page 2
t = Celsius temperature
What are the freezing and boiling points of water on 3 different scales?
Fahrenheit Celsius
Kelvin
Boiling Point
Freezing Point
Practice Problem
Temperature Scale Conversion The highest atmospheric temperature ever recorded on Earth was
57.8ºC. Express this temperature both in degrees Fahrenheit and in kelvins.
1. List the given and the unknown values.
Given:
t = 57.8ºC
Unknown:
TF = ?ºF
T = ?K
2. Write down the equations for temperature conversions.
TF = 1.8t + 32.0
T = t + 273
3. Insert the known values into the equations, and solve.
TF = (1.8  57.8) + 32.0 = 104 + 32.0 = 136ºF
T = 57.8 + 273 = 331 K
II. Relating Temperature to Energy Transfer
• Temperature changes indicate an energy transfer.
• Heat is the energy transferred between objects that are at different temperatures.
• The transfer of energy as heat always takes place from a substance at a higher temperature to
a substance at a lower temperature.
• For example, if you hold a glass of ice water in your hands, energy will be transferred as heat
from your hand to the glass.
Ch13 Heat and Temperature Page 3
Quiz:
1. Temperature is a measure of what?
2. What are three temperature scales?
3. What is the temperature at which an object's energy is minimal?
4. Convert 55⁰F to ⁰C and K.
5. What happens when two objects at different temperatures come into contact with each other?
Ch13 Heat and Temperature Page 4
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