Heat and Temperature (And 6th year Magnetism): Flashcards
temperature
the measure of the hotness or coldness of a body
SI unit for temperature
the kelvin K
for practical work
ºC
ºC =
K - 273.15
Δθ = 5ºC =
5K
thermometric property
the physical property of a thermometer that changes measurable with temperature
4 thermometric properties
length of a column of mercury
emf of a thermocouple
resistance of a wire
colour of liquid crystals
what is the standard thermometer
the laboratory mercury thermometer
to calibrate a liquid in glass thermometer experiment
calibration graph, y axis
length cm
to calibrate a thermometer experiment
calibration graph, x axis
temperature ºC
to calibrate a liquid in glass thermometer
2 points on accuracy
- use a stirrer to ensure water has uniform temperature
2. avoid error of parallax when using the half metre stick to measure the length of the liquid in a glass tube
calibrating a thermocouple thermometer y-axis
emf (mV)
what do you place in the substance you want to check temperature of with thermocouple thermometer
hot junction
reference junction
cold junction
how to find temperature of reference junction
finding the value of the point of intersection of the graph and the x-axis
2 different thermometers
don’t agree
the values of different thermometers
will most likely not be the same
why do the 2 values not agree?
different thermometers based on different thermometric properties respond in a different way to a given rise in temperature giving somewhat different values
is there a correct thermometer?
we choose a standard thermometer against which all other thermometers can be compared
what is special about a clinical thermometer?
there is a constriction
what is the constriction in the medical thermometer designed to do?
designed to stop the liquid from falling back into the reservoir when the thermometer is taken out of the patient’s mouth
how is the liquid in the medical thermometer got back into the reservoir
it is shaken before used on next patient
2 uses of a thermocouple thermometer
in an oven or a boiler
how is the thermocouple thermometer read?
the emf generated would be translated to a temperature reading
what flows between hotter and cooler substance?
heat energy
atoms in hot and cold substances moving in
moving in a 3 dimensional type of vibration
atoms in hot and cold substances have what energy
kinetic and potential energy
energy inside hot and cold substances
internal energy
which substance has more internal energy
the hotter substance
why does the hotter substance have more internal energy?
the kinetic energy is greater due to vibrations in the hotter substance