Transcript Energy - Denton ISD

UNIT 4 REASSESSMENT REVIEW
Energy Conversions
Heat Travels
Conduction, Convection, Radiation
DIRECTIONS
To start click “Slide Show”
and “From Beginning”
As you go through the
PowerPoint, take DETAILED
notes on –
Energy Conversions
Direction of Heat
Ways Heat Travel
WHAT IS ENERGY
Energy can be defined as the ability to do
work.
Work only occurs when something is using
energy.
BEFORE YOU START, REVIEW THE SEVEN FORMS
OF ENERGY
Mechanical (kinetic & potential)
Thermal (moving particles)
Electrical ( electrically charges particles)
Radiant (light, travels in waves through space)
Nuclear (stored in nucleus of atom)
Sound (vibrations through matter)
Chemical (stored in the bonds of compounds)
ENERGY CONVERSION
Energy can be changed from one form to another. Changes in the form
of energy are called energy conversions.
All forms of energy can
be converted into other
forms.
ENERGY CONVERSIONS
The sun’s light energy goes through solar panels and can be converted directly into electricity.
ENERGY CONVERSIONS
Green plants
convert the sun’s
light energy
(electromagnetic)
into chemical
energy (starches
and sugars).
OTHER ENERGY CONVERSIONS
 In a battery, chemical energy is converted into electric energy.
 How a hydro electric dam works – Moving water has mechanical
energy the is converted to electrical energy by a generator.
ENERGY CONVERSIONS
In an automobile engine:
1. the chemical energy in fuel is
burned to convert 2. into heat energy.
3. The heat energy is then changed into mechanical energy to move the
car. (it also turns into sound energy
right!?)
CHEMICAL  HEAT MECHANICAL
THE LAW OF CONSERVATION OF ENERGY
Energy can be neither created nor destroyed by ordinary
means.
 It can only be converted from one form to another.
 If energy seems to disappear, then scientists look for it –
leading to many important discoveries.
WATCH THIS!!!
VOCABULARY WORDS – STOP!
TEST YOUR SELF NOW. IF YOU CAN’T DEFINE &
GIVE EXAMPLES GO BACK AND REVIEW AGAIN.
energy
mechanical energy
heat energy
chemical energy
radiant energy
electrical energy
nuclear energy
energy conversion
Law of Conservation of Energy
DIRECTION OF HEAT TRANSFER
• Heat always moves from a warmer place to a cooler place.
• Hot objects in a cooler room will cool to room temperature
as they give off heat energy.
• Cold objects in a warmer room will heat up to room
temperature as they gain heat energy.
DIRECTION OF HEAT TRANSFER
Heat always moves
from hotter materials
to the cooler
materials.
Your warm tea will
give energy to the
ice cubes until both
the tea and the ice
have reached the
same temperature.
HEAT TRAVELS IN THREE WAYS, BUT
HOW CAN WE TELL THE DIFFERENCE?
HEAT TRANSFERS
EXAMPLE OF CONDUCTION
• A piece of cheese melts as heat is
transferred from the meat to the cheese
(Contact)
EXAMPLES OF CONVECTION:
Have you ever noticed that the air near the ceiling is
warmer than the air near the floor? Or that water in a
pool is cooler at the deep end?
Examples: air movement in a home, pot of heating
water.
EXAMPLES OF RADIATION
1.
Fire
2.
Heat Lamps
3.
Sun
Click Here to learn a conduction
convection radiation song… you’re
going to love it 