thermal energy & heat heat and its uses. thermal energy & heat 16.1 thermal energy and...
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Thermal Energy & Thermal Energy & HeatHeat
Heat and Its UsesHeat and Its Uses
Thermal Energy & Thermal Energy & HeatHeat
16.1 Thermal Energy and 16.1 Thermal Energy and MatterMatter
THERMAL ENERGY & MATTER: Journal
1. In which direction does heat flow spontaneously?2. Define TEMPERATURE3. How is THERMAL ENERGY transferred?4. What are the factors that determine the THERMAL
ENERGY of a material?5. Which type of material heats more, one with a
high specific heat, or one with a low specific heat?6. Is WORK 100% efficient? How do you know?
THERMAL ENERGY & MATTER
Work and Heat- work is never 100% efficient. Some is always lost to heat.
THERMAL ENERGY & MATTER
Heat- the transfer of thermal energy from one object to another because of a temperature difference.
In what direction does heat flow spontaneously?
FROM HOT to COLD
THERMAL ENERGY & MATTER
Temperature = measure of how hot or cold something is compared to a reference point.
Temperature is the average kinetic energy of the particles in an object.
In the image below, where is average kinetic energy greater?
Higher temperature
THERMAL ENERGY & MATTERHeat flows DOWN the bar through
COLLISIONS.Collisions transfer thermal energy from
hot to cold.
THERMAL ENERGY & MATTER
Thermal energy- total potential and kinetic energy in an object. It depends on mass, temperature, and phase of an object.If both objects are in the same phase & at the same temperature, which one has MORE thermal energy?
Because thereare MORE
particles moving around.
THERMAL ENERGY & MATTER
Thermal expansion/contraction - change in volume of a material due to temperature change.
Occurs because particles of matter collide more or less as temperature changes.
Thermal expansion Also, wrap on beaker and lava lamp
THERMAL ENERGY & MATTER
Specific Heat – amount of heat needed to raise ONE gram of a material ONE degree Celsius.
THERMAL ENERGY & MATTER
The LOWER a material’s specific heat the MORE its temperature rises when energy is added.Which will heat faster (has the lower specific
heat)?Water? Or Lead?
YES!
Specific heat of water = 4.18 J/g°C Specific heat of lead = 0.46J/g°C
Thermal Energy & Thermal Energy & HeatHeat
16.2 Heat and Thermodynamics16.2 Heat and Thermodynamics
HEAT TRANSFER
What type of HEAT TRANSFER is occurring in the pictures? Conduction, convection or radiation?
CONDUCTION – The transfer of thermal energy with no
transfer of matter.
HEAT TRANSFER
What type of HEAT TRANSFER is occurring in the pictures? Conduction, convection or radiation?
CONVECTION – The transfer of thermal energy when particles
of a liquid or gas move from one place to another
HEAT TRANSFER
CONVECTION – in the earth and sun
HEAT TRANSFER
What type of HEAT TRANSFER is occurring in the pictures? Conduction, convection or radiation?
RADIATION – The transfer of thermal energy by waves
moving through space. ALL OBJECTS radiate energy!
THERMODYNAMICS
The study of conversions between thermal energy and other forms of energy.
THERMODYNAMICS
First Law: Energy is Conserved
Thermal Energy & Thermal Energy & HeatHeat
16.3 Using Heat16.3 Using Heat
THERMAL ENERGY & MATTER: Journal
1. Define Convection, Conduction and Radiation
2. Give an example of each.3. Write a sentence describing how each
is important to our everyday lives.4. How do we use heat in our everyday
lives?
PART 2 - USING HEATHEAT ENGINES
The two main types of heat engines are External combustion and Internal Combustion
External = power plants
Internal = car engine
PART 2 - USING HEATExternal combustion – produces
electricity at power plants.Water is heated by a fuel and the pressurized
steam spins a turbine.http://www.eas.asu.edu/~holbert/eee463/coal.html
PART 2 - USING HEATHEAT ENGINES
External combustion – nuclear power plants.
USING HEAT
Internal combustion – car engines.
The fuel (gas) is compressed and ignited (lit) to drive a piston.
USING HEAT
Internal combustion – car engines.
Four-stroke engine.