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Temperature, Heat and Internal Energy
Temperature
The degree of hotness
Temperature, Heat and Internal Energy
Temperature Scales
(1) Ice point 0oC (melting ice)
(2) Steam point 100oC (boiling water)
Celsius Scale
Temperature, Heat and Internal Energy
Kelvin Scale
Ice pt : 273 KSteam pt : 373 K
1K = 1oC
T(in K) = T (in oC) + 273
Absolute zero-273oC or 0 K
Temperature, Heat and Internal Energy
Particle motion and Temperature
Examine the relationship HERE
Temperature
Particles move faster
Average K.E. increases
Temperature, Heat and Internal Energy
ThermometerInstrument to measure temperature
Common type of thermometer:
Liquid-in-glass thermometer(1) mercury-in-glass(2) alcohol-in-glass
Temperature, Heat and Internal Energy
Clinical Thermometer
Thermal Expansion in liquid
Around 37oC
Narrow bend : avoid running back
Temperature, Heat and Internal Energy
Rotary Thermometer
Thermal Expansion in solid
About –40 to 60oC (small range)
Temperature, Heat and Internal Energy
Thermocouple Thermometer
Voltage / current
-200oC to 1700oC (very large range)
Industry (ovens / furnaces)
Temperature, Heat and Internal Energy
Resistance ThermometerResistance, Current
-200oC to 1200oC
Industry
Temperature, Heat and Internal Energy
Thermistor Thermometer
Resistance, Current
Up to hundreds
Home use
Not very accurate
Temperature, Heat and Internal Energy
Calibration of a Thermometer
Click HERE to see the calibration of a thermocouple thermometer
Temperature, Heat and Internal Energy
Internal energy
K.E. + P.E.
Force between particlesDistance P.E. Solid < liquid < gas
Motion of particles
T increases K.E. increases
T oC
Temperature, Heat and Internal Energy
Heat
TA > TB
HeatingA B
Temperature, Heat and Internal Energy
REMARKS ON HEATING
1. Heating ends when TA = TB
2. Energy Transfer:(a) Doing work - force(b) Heating – temp. diff.
3. Power of heating?* P = E / t* in W, kW* Joulemeter / kWh meter
and stop watch