What is Heat

What Is Heat?

• Heat :
• Is the energy transferred between
objects that are at different
temperature.
• When two objects at different
temperatures come into contact,
energy is transferred from the
object that has the higher
temperature to the object that has
lower temperature.

Heat & Thermal Energy
• Thermal energy:
• Is the total kinetic energy of
the particles that make up a
substance.
• It depends partly on
temperature.
• It also depends on how much
of a substance there is.

Conduction, Convection &
Radiation

• Conduction:
• Thermal conduction: Is the
transfer of thermal energy from
one substance to another
through direct contact.

• Conductors & Insulators:
• Substances that conduct thermal
energy very well are called
thermal conductors.
• Substances that do not conduct
thermal energy very well are
called thermal insulators.

• Convection:
• The transferee of thermal energy
by the movement of a liquid or a
gas.

• Radiation:
• Is the transfer of energy as
electromagnetic wave.

Radiation & Greenhouse Effect
1. Visible light passes through the
atmosphere & heats Earth.
2. Earth radiates infrared waves,
some of which escape into
space.
3. Greenhouse gases ( water vapor
& CO2) trap some of the
radiated energy near Earth’s
surface.

Heat & Temperature
Change
• Thermal Conductivity:
• Is the rate at which a substance
conducts thermal energy.

• Specific Heat:
• Is the amount of energy needed
to change the temperature of 1
Kg of a substance by 1 °C

Heat, Temperature &
Amount
• To calculate heat:
heat (Joules)= specific heat X
mass X change in
temperature