Notes-Heat & Temperature
Chapter 12 in your Physics book/Chapter 21 & 22 in the Conceptual Book
Temperature and heat are different.
Heat is the internal energy which is transferred from bodies of higher internal energy to bodies of lower
internal energy. (heat does work & work produces heat)
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Symbol used to write heat is ____________Q____________
Unit of measurement is the _____________calorie_____________
Instrument used to measure heat is the _____calorimeter______________
Temperature is the measure of the average kinetic energy of a substance based on the expansion and
contraction of the substance.
 Unit of measurement is the _____degree__________
3 scales:
1. Celsius
2. Fahrenheit
3. Kelvin
 Instrument used to measure temperature is the Thermometer
 Fixed points are based on the freezing point of water :0 degrees C, 32 degrees F
And the boiling point of water:100 deg C, 212 deg F
Formulas used to convert temperature scales
 Celsius to Fahrenheit and vice versa

Celsius to Kelvin and vice versa
Examples:
1. What is the Celsius value for 65°F?
2. 200° C is the same temperature as what value on the Fahrenheit scale?
3. A substance has a melting point of 625 K. At what Celsius temperature would this substance melt?
4. What would be the corresponding temperature for the Kelvin scale for 100° C?
Laws of Thermodynamics:
1st Law of Thermodynamics: When mechanical, electrical, or any kind of energy is converted to heat,
all energy is conserved.
2nd Law of Thermodynamics: heat flows from a hotter to a colder body but NEVER vice versa.
Specific Heat of a substance is the amount of heat needed to raise the temperature of a unit mass of
that substance through one degree.
The formula that uses specific heat is
Q=mcΔT
Q= heat
m=mass
c=specific heat
ΔT=change in temperature
The higher the specific heat, the more heat is required to cause a change in temperature. Substances
with higher specific heats require more loss of heat energy to experience a lowering of their
temperature than do substances with a low specific heat. Some specific heat values are presented in
the table below.
Material
Specific Heat (J/kg°C)
Specific Heat (cal/g°C)
Specific Heat(J/g °C)
Water
4,184
1
4.184
Aluminum
900
.215
.9
Steel
470
.12
.470
Silver
235
.0558
.235
Oil
1,900
1.900
Concrete
880
.880
Glass
800
.2
.800
Gold
129
.0301
.129
Wood
2,500
.2500
Alcohol
2,400
.58
2.4
Iron
460
.108
.460
Copper
390
.092
.390
** 1 J=0.239 cal and 1 cal=4.184 J
Water has the highest specific heat which means that water is slow to heat but is also slower to lose
heat.
Examples:
5. How much energy is required to heat 35 grams of gold from 10°C to 50°C?
6. Calculate the number of calories given off by 500 grams of water that cools from 50°C to 20°C.