Understanding Temperature: Kelvin, Celsius, Fahrenheit and Their Conversion, Exams of Thermodynamics

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Temperature Notes

• Kelvin, Celsius, Fahrenheit
• Write notes, put in por7olio.
• Everything Underlined – COPY IT!
• Study. Read over notes daily.
• Enjoy the learning process.

• Temperature is how hot or cold something is. Temperature is really a measure of how fast the atoms and molecules that make up a substance are moving (this movement is sub-­‐microscopic; you cannot see it).
• A thermometer measures the temperature of something, showing how hot or cold it is.
• There are many different types of thermometers that measure the temperature of different things. We use thermometers to measure the temperature of the air, our bodies, food, and many other things. There are analog and digital thermometers. An analog thermometer shows the temperature on a scale or dial; a digital thermometer shows the temperature as a number.
• The higher the number above zero, the higher the temperature.

• The units of the Celsius and

Fahrenheit scales are called

degrees. The symbol for

degree is °.

• The units of the Kelvin scale

are called Kelvins.

• A change of one degree of

temperature Celsius is the same as

a change of one Kelvin.

• A change of one degree

Fahrenheit is a smaller change in

temperature.

• Each temperature scale is useful

for different things.

• Celsius (also called CenTgrade) is

a measure of temperature that is

abbreviated C.

• Water freezes at 0°C and boils at

100°C.

• This scale was developed by

Anders Celsius in 1742.

• Kelvin is a measure of temperature that is abbreviated K.
• Kelvin is a temperature scale designed so that 0 (zero) K is defined as absolute zero, and the size of one unit is the same as the size of one degree Celsius.
• (Absolute zero is a hypotheTcal temperature at which all molecular movement stops).

Conversion Formulas If you know the temperature in one temperature scale you can use a formula to figure out what it is equivalent to in other scales. The conversion formulas are in the table that follows. COPY THIS CONVERSION FORMULA CHART IN YOUR NOTES

Temperature Conversion Formulas: COPY THIS CONVERSION FORMULA CHART IN YOUR NOTES

Examples:

• Here is an example problem that explains how to convert a temperature from degrees on the Celsius scale to Kelvin.
• Celsius to Kelvin Problem #
• Convert 27° C to Kelvin.
• Celsius to Kelvin SoluTon #
• K = °C + 273
• K = 27 + 273
• K = 300
• 300 K
• Note that the answer is 300 K. Kelvin is not expressed in degrees. COPY THIS INFORMATION IN YOUR NOTES

Examples:

• Celsius to Kelvin Problem #
• Convert 77° C to Kelvin.
• Celsius to Kelvin
• SoluTon #
• K = °C + 273
• K = 77 + 273
• K = 350
• 350 K COPY THIS INFORMATION IN YOUR NOTES