
The measure of the average kinetic energy
of particles.
Temperature doesn’t depend on the number of particles
Thermal energy is the total kinetic energy of particles.
Thermal energy depends upon
temperature and the number
of particles.
If both beakers are at
100 degrees C, which
one has more thermal
energy?
Thermal expansion is the increase in volume that results from an
increase in temperature.
less
dense
more
dense
less heat
more heat
When something is heated, its particles have more kinetic energy, so the particles
move faster and move apart, causing expansion. The mass stays the same, but the
volume increases as it expands, so density decreases.
Heat is the energy that is transferred between
objects of different temperatures.
Which way is the heat energy moving in each picture?
Specific heat refers to the different rates at which substances become warmer or
cooler.
Substances with a high specific heat, like water, require a lot of energy to show an
increase in temperature.
As the sun shines throughout the day, which will heat up faster, the air or a
swimming pool? Why?
Energy from the Sun travels is waves.
The Sun’s energy comes in different forms.
 Visible light – we can see this
 Infrared radiation – most of the warmth we feel
 Ultraviolet radiation – high energy radiation
How is the heat energy being transferred in this picture? Is it
Radiation, Conduction, or Convection? Explain.
Conduction
Conduction is the transfer of energy from one object to
another through direct contact.
How is the heat energy being transferred in this picture? Is it
Radiation, Conduction, or Convection? Explain.
Radiation
Radiation is the transfer of energy as electromagnetic waves.
Radiation can transfer energy between objects that are not in direct
contact with each other.
How is the heat energy being transferred in this picture? Is it
Radiation, Conduction, or Convection? Explain.
Convection
Convection is the transfer of energy due to the movement of matter.
A convection current occurs because most matter becomes less dense as its
temperature increases. When matter is heated, it undergoes thermal expansion,
making it less dense. The less dense matter is forced upward by the
surrounding colder, more dense matter that is sinking. As the hot matter rises,
it cools, becoming more dense and causing it to sink. This is what happens
when water boils.