Heat and temperature

HEAT AND TEMPERATURE

KINETIC MOLECULAR THEORY

Kinetic Theory of Matter:

is the idea that matter is made up of tiny particles (atoms or molecules) that are always in motion.

THE KINETIC MOLECULAR THEORY

Multiple Choice

What is the kinetic theory of matter?

• The kinetic theory of matter states that matter is not affected by temperature or pressure.
• The kinetic theory of matter states that all particles of matter are in constant motion.
• The kinetic theory of matter states that matter is made up of tiny particles called atoms.
• The kinetic theory of matter states that matter is stationary and does not move.

Temperature

 

is defined as the measure of hotness or coldness of an object (degrees Celsius, or degrees Fahrenheit, or kelvins).

  is related to the average translational kinetic energy per molecule in a substance

Temperature

Thermometer

  is an instrument that measures temperature by comparing the expansion and contraction of a liquid as it gains or loses thermal energy.

Infrared thermometer

  measures temperature by the radiation a substance emits.

Three different temperature scales differ in zero point and divisions:

•Celsius scale

  freezing point of water: 0°C

  boiling point of water: 100°C

  division: 100 degree units

•Fahrenheit scale

  freezing point of water: 32° F

  boiling point of water: 212° F

  division: 180 degree units

•Kelvin scale (used in scientific research)

  freezing point of water: 273 K

  boiling point of water: 373 K

  division: same-size increments as Celsius scale

Multiple Choice

which one has the same division increments as degrees celsius?

• kelvin
• fahrenheit
• rankine
• newton

Multiple Choice

There is twice as much molecular kinetic energy in 2 liters of boiling water as in 1 liter of boiling water. Which will be the same for both?

• Temperature.

• Thermal energy

• Both temperature and thermal energy

• none of the above

​Absolute Zero

Absolute zero or zero K

  is the lowest limit of temperature at –273°C  where molecules have lost all available kinetic energy. A substance cannot get any colder.

What Is Heat?

  Heat

  is defined as a flow of thermal energy due to a temperature difference.

The direction of heat flow is from a
higher-temperature substance to a
lower-temperature substance

 The temperature of the sparks is very high, about 2000°C.  That’s a lot of thermal energy per molecule of spark.  However, because there are few molecules per spark, internal energy is safely small.  Temperature is one thing;  transfer of energy is another