temperature i. definition- the quantity that tells us how hot or cold something is (compared to...

Temperature

I. Definition- the quantity that tells us how hot or cold something is (compared to something else)

II. It is expressed by a number on a scale

Temperature

III. Nearly all matter expands when its temperature increases

IV. The common thermometer measures temperature by showing the expansion or contraction of a liquid

TemperatureV. There are 3

common temp scales

A. Fahrenheit- used in the United States

B. Celsius- most commonly used (lab

and the world)A. Kelvin- used in

scientific research

A poem

30 is hot 20 is nice 10 put a coat on Zero is ice

Temperature Conversions

Review

1) What are absolute zero for

Kelvin? Celsius?2) What are the

freezing points of water for

Kelvin? Celsius? Fahrenheit?

Review

3) What are the boiling points of water for

Kelvin? Celsius? Fahrenheit? 4) What is normal

body temp in Celsius?

Review6) Which temp is correct?a) 37°F b) -2°C c) 300 K

7) Which temp is correct? a) 40°C b) 98.6° F c) 37°C

8) Which temp is correct?a) 40°F b) 275 K c) 30°C

Temperature and Kinetic Energy

States of Matter and Kinetic Energy

Remember… that KE is the energy of motion

Temperature is

related to the force and the amount of collisions that happen between atoms…both increase

HeatDefinition- the energy that transfers from one object to another b/c of a temperature difference

Temperature and Heat are related

…but being related doesn’t make you the same

Temperature and Heat are related….but being related doesn’t

make you the same

Temperature and Heat are related

Temperature is related to the average kinetic energy of the particles in a substance.

Heat

• If you touch a hot stove…energy will enter your hand

• If you touch ice, energy will pass out of your hand

• When in contact with each other…Energy always passes from the warmer to the cooler substance

Heat• Why does the energy

move at all?• It will try to obtain

thermal equilibrium• When a thermometer

is in contact with a substance, the energy flows until the thermometer is the same temp

• Sooo, the thermometer is now showing it’s own temp

Why aren’t the earth and sun in equilibrium with each other?

Unit of Heat

• In the metric system, heat is measured in units of calories, which are defined as the amount of heat required to raise the temperature of one gram of water from 14.5oC to 15.5oC.

Calculating Calories in food…burn the food, measure the energy that is

released as heat

The reaction's energy is found by subtracting the initial temperature from the final, then multiplying by the amount of water used, in this case, 100 mL. If the initial temperature is 24 degrees C and the final is 26 degrees C, we get ( 26 -- 24 ) x 100 = 200 calories.

FYI - Btu (Bristish thermal units ) are the quantity of heat required to change the temperature of 1 pound of water by 1° F, which is used in heating and a/c

Unit of Heat

• We will use both Joule and calorie in our next calculations

• In the SI system, which is the modern metric system (1960)….the unit of heat is a Joule

• Just as 1 day= 24 hours , 1 calorie = 4.186 J