Energy is measured in different ways.
Thermal energy is measured in English unit BTU.
One BTU is the amount of energy to raise on Pound of water
to one degree Fahrenheit it higher.
One average candy bar contains about one thousand BTU.
Energy can change its form but there is no creation or
destroying form of energy. Energy must be remained in one
of known forms.
For instance, chemical energy of a battery transformed to
electrical energy which then can be changed to light
energy in a flashlight.
Food, a chemical form of energy can be converted to heat
energy in living bodies.
Any extra in taking of food (over eating) will result to
fat cells accumulation, storing energy for a future use.
Talking on a phone, transforms acoustic energy to
electrical energy in one side and vice versa in the other
side.
Engine in a car change chemical energy stored in gasoline
to heat energy and later to mechanical energy.
Heater or a lamp can change electrical energy to a
combined form of heat and light energy.
Television change electrical energy to both form of
acoustic and light energy.
Conduction is a direct way of passing energy from one body
to another. Stirring a cup of tea, heats up the tea spoon
by conducting.
While metals are excellent, wood and plastics are very
poor heat conductors. That is why a pan is made by a
plastic handle and metallic body.
Convection transfers heat via fluids or gases. In boiling
water, you may notice the turbulent movements as a result
of heat exchange between differ temperature parts.
Hydrogen, Helium and Carbon are the other elements found
abundantly in universe, and the life on earth depends
mostly to them. Carbon in its pure form appears as diamond
and in a less form as coal.
The outer electrons have a loose dependency to nucleus,
and by leaving its orbit, make and atom positively
charged. It any atom gains additional electron, it will
show negative charge.
The other name for a charged atom is “ion”.
Freely movement of electrons between atoms makes a
phenomenon called electric current.
Passing electrons from one atom to the neighboring atom in
a chain cause the flow of electricity in a wire.
As you observe, the steady movement of electrons makes on
unbalanced condition for all atoms involved.
In a natural pressure of getting balanced, atoms look for
a free electron to fill their lost electron. Saying that
an unbalanced atom has a “Positive charge” means that it
has too many protons.
So what do positive and negative charges have to do with
electricity?
There are several ways to produce large number of ions as
well as negative electrons. Positive atoms have a strong
attraction for electrons. The same goes for free
electrons. So the two attractions balance each other out.
Being more positive or negative means more attraction
between them. The overall such an attraction is called
“charge”.
By moving electrons amidst atoms, a current is developed.
Such a phenomenon happens in a long of wire. Electrons by
passing between atoms create an electrical current.
As an example of convection, we may refer to wind in the
coastlines which happens by a replacement of light warm
air by a heavier cold air.
Radiation, the last form of this kind of energy, without
using the conventional medium as conduction and
convection, transfers its energy in empty space; that is
why the energy of sun reaches to us earth.
By moving in a straight line, the sun rays radiate.
Hitting the sunlight to the surface of earth, it is
absorbed or reflected. As it is obvious, the darker parts
absorb more radiation and the lighter parts reflect more
radiation. That is the reason we wear light clothes in
summer times.
