1. HEAT ANDHEAT AND
TEMPERATURETEMPERATURE
Autora: Marta García T.Autora: Marta García T.

2. WHAT IS HEAT?WHAT IS HEAT?
 HeatHeat is thermal energy transferred from ais thermal energy transferred from a
warmer body or system, to a colder one. So,warmer body or system, to a colder one. So,
one system releases heat and the other oneone system releases heat and the other one
absorbs it.absorbs it.
 This thermal transfer will stop when bothThis thermal transfer will stop when both
systems have the same temperature (systems have the same temperature (thermalthermal
equilibriumequilibrium).).
http://www.quimicaweb.net/grupo_trabajo_ccnn_2/tema3/index.htm
Autora: Marta García T.Autora: Marta García T.

3. Just to think a bit….Just to think a bit….
a)a) Is it correct to say that hot objects emit heatIs it correct to say that hot objects emit heat
and cold objects emit cold?and cold objects emit cold?
b)b) Is it true that a blanket give us heat?Is it true that a blanket give us heat?
c)c) What direction does heat flow in?:What direction does heat flow in?:
Autora: Marta García T.Autora: Marta García T.

4.  There are two units of measure for heat:There are two units of measure for heat:
 JoulesJoules (J)(J)
 CaloriesCalories (cal)(cal)
 1J = 0,24 cal1J = 0,24 cal
Autora: Marta García T.Autora: Marta García T.

5. WHAT IS TEMPERATURE?WHAT IS TEMPERATURE?
 TemperatureTemperature is the amount of heat in a bodyis the amount of heat in a body
or system.or system.
• The instrument which measuresThe instrument which measures
temperature is thetemperature is the thermometerthermometer..
Autora: Marta García T.Autora: Marta García T.

6.  There are three scales to measure temperature:There are three scales to measure temperature:
 Celsius ScaleCelsius Scale: is the most common scale. It is: is the most common scale. It is
divided into a hundred parts, from the freezing pointdivided into a hundred parts, from the freezing point
of water (0 ºC) to the boiling point (100 ºC).of water (0 ºC) to the boiling point (100 ºC).
 Fahrenheit ScaleFahrenheit Scale: used in English-speaking: used in English-speaking
countries. The freezing point of water is 32 ºF, andcountries. The freezing point of water is 32 ºF, and
the boiling point is 212 ºF.the boiling point is 212 ºF.
 Kelvin ScaleKelvin Scale: used by scientists. The freezing point: used by scientists. The freezing point
of water is 273 K, and the boiling point is 373 K.of water is 273 K, and the boiling point is 373 K.
Autora: Marta García T.Autora: Marta García T.

7. Autora: Marta García T.Autora: Marta García T.

8. HOW DOES HEATHOW DOES HEAT
TRANSFER?TRANSFER?
 There are three ways for heat to beThere are three ways for heat to be
transferred, depending on the material:transferred, depending on the material:
 ConductionConduction: this process occurs in most solids.: this process occurs in most solids.
Heat is transferred by direct contact.Heat is transferred by direct contact.
Autora: Marta García T.Autora: Marta García T.

9.  ConvectionConvection: occurs in liquids and gasses. Heat: occurs in liquids and gasses. Heat
is transferred by the movement of currents.is transferred by the movement of currents.
Autora: Marta García T.Autora: Marta García T.

10.  RadiationRadiation: is the transfer of heat by: is the transfer of heat by
electromagnetic waves. Contact between theelectromagnetic waves. Contact between the
source and the heated substance is notsource and the heated substance is not
necessary, so is the way heat transfers in thenecessary, so is the way heat transfers in the
universe (where there is no matter).universe (where there is no matter).
Autora: Marta García T.Autora: Marta García T.

11. Label this pictureLabel this picture
about heat transfer:about heat transfer:
http://www.profes.net/varios/videos_interactivos/definitivo.swf
Autora: Marta García T.Autora: Marta García T.

12. WHAT ARE THE EFFECTS OFWHAT ARE THE EFFECTS OF
HEAT?HEAT?
1)1) Changes of States:Changes of States:
 EndothermicEndothermic: changes produced by heat: changes produced by heat
absorption: melting, evaporation andabsorption: melting, evaporation and
sublimation.sublimation.
 ExothermicExothermic: changes produced by heat loss:: changes produced by heat loss:
solidification, condensation and regressivesolidification, condensation and regressive
sublimation.sublimation.
Autora: Marta García T.Autora: Marta García T.

13. Do you remember theDo you remember the
names for the changesnames for the changes
of state?of state?
Autora: Marta García T.Autora: Marta García T.

14. 2)2) ExpansionExpansion: it is the increase in volume which: it is the increase in volume which
occurs when a system gains heat. Particlesoccurs when a system gains heat. Particles
move faster, so they occupy more space.move faster, so they occupy more space.
3)3) ContractionContraction: it is the decrease in volume which: it is the decrease in volume which
occurs when a system cools. Particles moveoccurs when a system cools. Particles move
more slowly, so they occupy less space.more slowly, so they occupy less space.
http://www.educared.net/aprende/anavegar
3/premiados/ganadores/c/651/Calor/index.
htm
Autora: Marta García T.Autora: Marta García T.