Download What is Energy?

6.P.3.1 Illustrate the transfer of heat energy from warmer objects to
cooler ones using examples of conduction, radiation and
convection and the effects that may result.
6.P.3.3 Explain the suitability of materials for use in technological
design based on a response to heat (to include conduction,
expansion, and contraction) and electrical energy
(conductors and insulators).
Energy is the power to change things.
Energy is the ability to do work.
The sun gives out light and heat energy.
Lights use electrical energy.
Batteries for flashlights use chemical
energy.
2 Kinds of Energy
One is doing work and the other is waiting
to do work.
Kinetic and Potential Energy
Potential Energy
Energy that is waiting to do work may
be:
• Sitting above ground level
• Is compressed or expanded in some way
• Found in the attraction between atoms
This is potential energy.
Potential Energy is stored energy which
means it has the ability to do work
Examples:
-A rubber band when you stretch it
-A yo-yo before you let it fall
Kinetic Energy
When we see energy doing work, it is
pushing or pulling, glowing, or changing
temperature.
This is kinetic energy.
Kinetic Energy is energy of motion
Examples:
-A rubber band flying through the air
-A yo-yo in motion
Forms of Energy
Mechanical energy
Thermal energy
Chemical energy
Electrical energy
Light energy
Sound energy
Nuclear energy
Mechanical Energy
• Energy associated with the motion or
position of an object.
• Examples:
– A hammer uses mechanical energy to do
work. The mechanical energy of the
hammer gives it the ability to apply the
force to the nail in order to move the nail.
Thermal Energy
• Total energy of the particles in a
substance or material.
• When the thermal energy of an object
increases, particles move faster,
making the temperature of the object
rise.
• Example:
– Ice cream melts when its thermal energy
increases
Chemical Energy
• Potential energy stored in chemical
bonds.
• Examples:
– Food that you eat
– Match used to light a candle
– Cells of your body
Electrical Energy
• Moving electrical charges produce
electricity.
• Examples:
–
–
–
–
Radios
Lights
Computers
Static shock
Electromagnetic Energy
• Energy that travels in waves.
• Examples:
– Visible light
– Ultraviolet radiation
– Microwaves
Nuclear Energy
• Energy stored in the nucleus of an atom
and is released during nuclear reactions.
• Examples:
– Sun
– Stars
– Nuclear Power plant
What kinds of energy can you identify?
Potential Energy Converted
to Kinetic Energy…
When stored energy begins to move,
the object now transfers from
potential energy into kinetic energy.
Standing still
Running
Stored potential chemical energy in a
flashlight’s batteries becomes light
energy when the flashlight is turned on.
Food is stored energy. It is stored as a
chemical with potential energy. When
your body uses that stored energy to do
work, it becomes kinetic energy.
When you talk on the phone, your voice is
converted into electrical energy, which
passes over wires. The phone on the
other end changes the electrical energy
into sound energy through the speaker.
A television changes electrical energy into
light and sound energy.
Let’s Review
• If you are holding a coin in your hand,
what type of energy does it have?
Potential, because it has the ability to do
work.
• If you drop the coin into a piggy bank,
what happens to the energy?
It is transferred from potential to
kinetic. Dropping the coin changes
the stored energy into motion.
A Power Plant
The energy transformation process is carried out in three stages:
•
•
•
Chemical energy in the fuel (gas or oil) is released as heat in
the boiler when it burns with air.
Heat converts water in boiler tubes to steam, which is then
used to drive a turbine that converts energy into mechanical
energy.
Mechanical energy drives an alternator to produce electrical
energy.
Law of Conservation of Energy
When energy changes form – the total
energy before and after is the same.
When you turn on a car, the chemical
energy in the gas is converted to
mechanical energy in the engine and
heat energy – but all energy can be
accounted for.
Temperature
• Measure of the average kinetic energy
of the individual particles in an object.
The particles of hot cocoa
move faster than those of
chocolate milk.
Which drink has particles
with the greater average
kinetic energy?
Hot cocoa
Heat
• Movement of thermal energy from a
substance at a higher temperature to
another at a lower temperature.
• Heat is thermal energy moving from a
warmer object to a cooler object.
How Is Heat Transferred?
• Heat is transferred by conduction,
convection, and radiation.
Conduction
• Heat is transferred from one particle of
matter to another without the movement of
matter itself.
• Example:
– Think of a metal spoon in a pot on the stove. Fast
particles of hot electric coil collide with slow
particles of cool pot. Particles of pot collide with
particles of water, which collide with particles of
spoon. As the particles move faster, the metal
spoon becomes hotter.
Convection
• Heat is transferred by the movement of
currents within a fluid (a liquid or gas).
• Example:
– When water at the bottom of a pot is
heated, particles move faster, and farther
apart. Heated water is less dense so it
rises to the top of the pot. The
surrounding cooler water flows into the
bottom of the pot in a circular motion
called convection current.
Radiation
• Transfer of energy by electromagnetic
waves.
• Radiation does not require matter to
transfer thermal energy.
• Example:
– You can feel radiation from a bonfire or
heat lamp from a distance.
Questions
_____________ energy is stored energy
which means it has the ability to do work.
A. Chemical
B. Mechanical
C. Kinetic
D. Potential
Energy is the ability to do __________.
A. nothing
B. work
C. everything
D. none of the above
______________ energy associated with
the motion or position of an object.
A. Chemical
B. Mechanical
C. Kinetic
D. Potential