Energy
Temperature
• Temperature is related to the average kinetic
energy of an object’s atoms or molecules.
Thermal energy
• Thermal energy is the sum of the kinetic and
potential energy of all the atoms in an object.
• Thermal Energy increases as the temperature
increases.
• At constant temperature, thermal increases if
mass increases.
Heat
• Thermal energy that flows from something at
a higher temprature to something at a lower
temperature is called heat.
• When you hold ice, how does your hands feel.
Does the ice remain frozen or does it melt?
Specific Heat
• The specific heat is the amount of heat
needed to raise the temperature of 1 kg of a
material by 1 degree Celsius or Kelvin.
Thermal Energy Change
• Changes in thermal energy can be calculated
as change in thermal energy equals mass
times change in temperature times specific
heat.
Positive Change
• When heat flows into an object and its
temperature rises, the change in temperature
is positive.
Negative
• When heat flows out of an object and its
temperature decreases, the change in
temperature is negative.
Question
• How do temperature and heat differ?
Answer
• Heat is thermal energy that flows from
something warmer to something colder while
temperature is related to kinetic energy of
atoms in a substance.
Calorimeter
• A calorimeter is used to measure specific heat.
Conduction
• Conduction is the transfer of thermal energy
through matter by direct contact of particles.
Conduction
• In conduction, the kinetic energy is transferred
as particles collide.
• Solids, particularly metals, are good conductors.
Convection
• The transfer of energy by the motion of
heated particles in a fluid is called convection.
Convection currents
• Convection currents transfer heat from
warmer to cooler parts of a fluid.
• Convection currents create rain forests and
deserts over different regions (parts) of Earth.
Radiation
• Radiation is energy transfer by
electromagnetic waves.
Radiation
• Some radiation is absorbed and some is
reflected when it strikes a material.
• Heat transfer by radiation is faster in a gas
than in a liquid or solid.
Flow of Heat
• Most living things control the flow of heat by
using special features such as fur, blubber, or
scales.
Insulator
• Insulators are materials that do not let heat
flow through them easily.
Insulators
• Gases such as air usually make better
insulators than liquids or solids.
• A vacuum layer in a thermos is a good
insulator because it contains almost no matter
to allow conduction or convection to occur.
Question
• What state of matter makes it a good
conductor? Heat insulator?
Answer
• Solids generally conduct heat better than
liquids or gases. Gases usually make better
insulators than liquids or solids.
Heating Systems
• Heating Systems warm homes and buildings.
• What type of heating system do you have?
Forced-Air System
• Forced-Air Systems are systems in which the
fuel heats the air, which is blown through
ducts and vents. Cool air is returned to the
furnace to be heated.
Radiator System
• A radiator system is a system in which hot
water or steam in a radiator transfers thermal
energy to the air.
Electric Heating System
• Electric Heating System is a system that has
electrically heated coils in ceilings or floors
which heat air by conduction.
Solar Energy
• Solar Energy is energy from the sun.
Passive Solar Heating
• Passive Solar Heating does not use mechanical
devices to move heat.
Active Solar Heating Systems
• Active Solar Heating Systems use solar
collectors to absorb radiant energy, which is
circulated through the building.
Heat Engine
• A heat engine is a engine that converts
thermal energy into mechanical energy.
• An internal combustion engine burns fuel
inside the engine in chambers or cylinders.
They only convert around 26% of chemicla
energy to mechanical energy. Not efficient
machines = pollution.
Heat Mover
• A Heat mover is a device that removes
thermal energy from one location and
transfers it to another location at a different
temperature.
Refrigerator
• A refrigerator contains a coolant that absorbs
heat from the inside of the refrigerator and
releases it on the outside as heat.
Air conditioners
• Air conditioners cool warm air.
Heat Pumps
• Heat pumps can both cool and warm air.
Evaporation
• The human body stays cool by evaporation of
sweat.
Question
• What are the three types of heating systems?
Answer
• Forced air systems, radiator systems, and
electric systems.
Energy Song
• http://www.cstephenmurray.com/Scienceson
gs.htm