1. Temperature
Chapter 13.1

2. What is Temperature?? 2 definitions:
“a measure of how hot or cold something is”
More scientific definition: “a measure of the average kinetic energy of the particles in an object”

3. How does kinetic energy relate to temperature?
Kinetic energy is how much energy of motion there is!
More kinetic energy = greater particle movement = more collisions and heat generated = higher temperature

4. How do we measure temperature?
Thermometer—an instrument that measures and indicates temperature
Higher temperatures cause an expansion in liquids (more KE  more collisions  liquids expand)

5. How do we measure temperature?
Liquid thermometers use this expansion property with mercury or colored alcohol to measure temperature
Increase temps  expansion of liquid  liquid therefore rises up on the thermometer to accommodate more space

6. Drawbacks of liquid thermometers…
Temps too cold  liquid could freeze!
Temps too hot  liquid could boil!
Therefore other thermometers rely on the expansion of metal (refrigerator thermometer) or change in current (digital thermometer) to gauge temperature

7. Measuring Temperatures
Fahrenheit scale: Water freezes at 32°F and boils at 212°C.
Most countries use the Celsius scale: Water freezes at 0°C and boils at 100°C.

8. How to convert between °F and °C.
Fahrenheit temperature =
(1.8 x Celsius temperature) + 32
Celsius temperature =
(Fahrenheit temperature – 32) / (1.8)
***Remember order of operations: PEMDAS
--P (parentheses)—complete these calculations first!
--E (exponents), M/D (Multiplication/Division), A/S (Addition/Subtraction)

9. Practice!
What is the temperature in degrees Fahrenheit of a room that is 40°C?
Fahrenheit = (1.8 x Celsius) + 32
Fahrenheit = (1.8 x 40) + 32
Fahrenheit = (72) + 32
Fahrenheit Temp = 104°F

10. Practice!
What is the temperature in degrees Celsius of an oven that is 300°F.
Celsius temperature = (°F – 32) / (1.8)
Celsius temp = (300 – 32) / (1.8)
Celsius temp = (268) / (1.8)
Celsius temp = °C

11. What is the lowest temperature possible??
Theoretically, the lowest temp possible is °C. This temperature is called absolute zero.
At absolute zero, the energy of an object is zero (which is technically not possible since all things are constantly in motion)

12. Kelvin Scale Scale invented based on absolute zero
Absolute zero = 0 K (Cannot go any lower)
No negative values on the Kelvin scale
Kelvin temperature = °C + 273

13. Practice
The highest temperature ever recorded on Earth was 57.8°C. Express this temperature in Kelvin.
Kelvin Temp = °C + 273
Kelvin Temp =
Kelvin Temp = K

14. Temperature practice!…Write the problems, then solve…
SHOW YOUR WORK TO RECEIVE CREDIT!
Convert 25°C to °F.
Convert 2°C to °F.
Convert 30°F to °C.
Convert 50°F to °C.
Convert 18°C to K.
Convert 32°C to K.
Convert 20°F to K.
Convert 15°F to K.

15. Temperature Lab!
Using a digital thermometer, record the temperatures of:
The room
A clinched hand (your body temp)
A cup of water
A cup of ice
***List and convert each of these temperatures to Fahrenheit, Celsius, and Kelvin **See chart on white board!***
***Turn in with your other calculations (worth a 50 point daily grade!)