What is Heat?
• Heat is the energy of particles moving from
warmer regions to cooler regions.
• Atoms are always moving and the motion of
these particles result in heat.
Heat
All matter has heat even
an ice cube. As more
heat is added to the
ice the molecules will
move faster and
eventually spread far
enough apart to
become a liquid.
Heat on the move
 Heat moves from a
warmer substance to
a cooler substance.
Temperature
 Temperature is the
measure of the average
kinetic energy of the
particles in a sample of
matter.
 As the particles move
faster and their average
kinetic energy becomes
greater the temperature
rises.
Heat and Temp not the same
 Heat is the total kinetic
energy of all the
particles in the sample.
 Temperature is the
measure of the
average kinetic energy
of all particles in a
sample.
Heat is measured in a unit
called calorie.
A calorie is the amount of heat
needed to raise the temperature
of one gram of water 1 degree
celsius.
Thermal Energy
Thermal energy is related to the
energy of the particles that make
up matter.
Thermal Energy
 Is the total energy of particles in the
material.
 This total includes both kinetic and potential
energy.
 Kinetic refers to motion/vibrations
 Potential refers to forces that act within or
between the particles.
Thermal Energy
 The more mass a
material has at the
same temperature the
more thermal energy it
has.
Specific Heat
 The amount of energy
required to raise the
temperature of 1 kg of
a substance one kelvin
is called its specific
heat.
 Measured in joules per
kilogram per kelvin
 J/ (kg x K)
Specific Heat
 Temperature does not rise and fall at the
same rate for all objects.
 The amount of heat required to raise the
temperature depends on the chemical
makeup of the material.
 Different materials need more or less heat to
change their temperature by the same
amount.
Freezing and boiling point
Scale
Freezing
Point
Boiling
Point
Absolute
Zero
Celsius
0
100
-273
Fahrenheit
32
212
-460
Kelvin
273
373
0
Absolute Zero
The coldest temperature possible.
All heat has been removed.
Freezing/ Melting
 Freezing point is the
temperature at which a
liquid changes to a
solid.
 Melting point is the
point at which a solid
changes to a liquid
Boiling Point
 Point when liquid
changes to a gas.
Boiling and Freezing points
Are different for different
substances.
Evaporation
 This occurs on the
surface of a liquid.
The atoms of the liquid
on the surface gain
enough heat energy to
escape as a gas.
Boiling
 When a liquid boils the bubbles form
throughout the liquid and rise out of the
liquid.
What is conduction
 Conduction is the
process of heat
transfer.
 Transfer of energy
through matter in
which energy moves
from particle to
particle.
Conductors and Insulators
 Metals are good conductors of heat.
 A conductor is a material that allows heat to
move through it easily.
 Insulators do not conduct heat well.
 Examples are wood, plastic, straw and
paper.
Convection
 Convection is the
transfer of energy by
the bulk movement of
matter in which
particles move from
place to place in a
fluid, carrying the
energy with them.
Convection Current
 Water boils at the bottom of a heated pot,
its particles move faster, and they also move
farther apart. As a result heated water
becomes less dense. The heated water
rises and the surrounding cooler water flows
into its place. This flow creates a circular
motion called the convection current.
Radiation
 Radiation is the
transfer of energy by
electromagnetic
waves.
 Radiation does not
require matter to
transfer thermal
energy
Solar Radiation
 Process by which energy from the sun can
be transported.
Sunlight
 Made up of infrared – heat
 Visible light – what we see
 Ultraviolet radiation.
 Ultraviolet radiation is harmful to your body.
SPF
 Sun Protection Factor is the is how
sunscreens are rated. The SPF ratings
indicate the amount of protection that a
sunscreen will provide.
Sunlight Dangers
 Eye disease
 Weaken bodies ability to fight some viruses
 Skin cancers