Thermal Effects

Question 1

Temperature

Answer 1

Temperature is the measure of hotness or coldness of matter.
It is specifically a measure of the average kinetic energy of each particle (molecules) in an object.
SI unit is kelvin(K)
It is measured using a thermometer

Question 2

Heat

Answer 2

Heat is the total energy that the moving particles (molecules) of an object possess.
It is the sum of kinetic energy and the potential energy of all the particles (molecules) in an object.
SI unit of heat is joules(J)
Heat is measured using a joule-meter OR a combination of instruments (calorimeter, thermometer) and some simple calculations

Question 3

Liquid glass thermometers

Answer 3

Mercury: Expands uniformly over a wide range of temperature
Narrow bore of the capillary tube: Makes the thermometer more sensitive
Bulb made of thin glass: Heat can be conducted quickly to the mercury (makes it more responsive)
Round glass stem: It acts as a magnifying glass to make reading the temperature easier

Question 4

Thermocouple

Answer 4

Two dissimilar metals are connected to form junctions. If these two junctions are kept
at different temperatures, then electric current flows through them. By measuring this
current we can predict the temperatures of either hot end or cold end.

Question 5

Heat and Temperature Relation

Answer 5

Temperature increases as heat is added to a substance.

Likewise, temperature decreases as heat is removed.

Question 6

Conuction

Answer 6

Conduction is where heat is transferred between two objects due to
physical contact between them. The molecules literally hit each other,
causing energy to transfer.

Question 7

Convection

Answer 7

Convection is where a hot part of a substance rises due to its lower
density, while cooler parts sink, creating cycles that transfer heat upwards.

Question 8

Radiation

Answer 8

And radiation is where heat is transferred through electromagnetic waves,
such as the radiation from the sun.

Question 9

Specific Heat Capacity

Answer 9

Specific Heat Capacity (c ) is the amount of heat energy (in joules) needed
to increase the temperature of 1 kg of a substance by 10C (or 1K).

Materials with a high specific heat capacity store more thermal energy per
Kg for the same increase in temperature.
 These take longer to heat or cool down.
 As these cool, they emit a lot of heat energy per degree C decrease in
temperature.
 For example, water has a particularly high specific heat capacity,
making it very useful for storing heat energy, and for transporting it, in
central heating.