Bell work The temperature of boiling water is 100° on the Celsius scale and 212° on the Fahrenheit...
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Transcript of Bell work The temperature of boiling water is 100° on the Celsius scale and 212° on the Fahrenheit...
Bell work
The temperature of boiling water is 100° on the Celsius scale and 212° on the Fahrenheit scale. Look at each of the following temperatures and decide whether you think that it is hot or cold:
60°F 60°C 37°F 37°C 0°C 100°F and 70°F
Objectives
• Describe how temperature relates to kinetic energy.
• Compare temperatures on different temperature scales.
• Give examples of thermal expansion.
Kinetic energy
Kinetic energy is the energy of motion. All moving objects have kinetic energy.
The amount of kinetic energy that an object has depends on the object’s mass and speed.
Kinetic energy
The faster the particles of an object are moving the hotter they are.
When you use a thermometer you are measuring the average kinetic energy of all the particles in an object.
• The gas particles on the right have a higher average kinetic energy than those on the left. So, the gas on the right is at a higher temperature.
• Average Kinetic Energy of Particles The motion of particles in matter is random, so individual particles have different amounts of kinetic energy.
• When you measure an object’s temperature, you are measuring the average kinetic energy of the particles in the object.
Measuring Temperature
The lowest temperature on the Kelvin scale is 0 K, which is called absolute zero.
Absolute zero (about −459°F) is the temperature at which all molecular motion stops.
It is not possible to actually reach absolute zero.
Objectives
• Describe how temperature relates to kinetic energy.
• Compare temperatures on different temperature scales.
• Give examples of thermal expansion.
Celsius to Fahrenheit
°C → °F
Fahrenheit to Celsius
°F → °C
Celsius to Kelvin
°C → K
K = °C + 273
Kelvin to Celsius
K → °C
°C = K − 273
Measuring TemperatureAs a substance's temperature increases,
its particles move faster and spread out.So, there is more space between them,
and the substance expands.
Thermal expansion is the
increase in volume of a
substance because of
an increase in
temperature.
Thermal Expansion-uses
We know that hot air rises. Hot air balloons work using this principal.
When a gas is heated its particles have more kinetic energy.
They move around more quickly, so there is more space between them.
As it expands, it becomes less dense than the air outside the balloon.