ENERGY – What is it?. WORK AND ENERGY. a. What is Energy?. Energy Is the Ability to Do Work. Energy is in everything. We use energy for everything we do; from making a jump shot to baking cookies to sending astronauts into space. There are two types of energy :
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WORK AND ENERGY
Energy Is the Ability to Do Work.
Energy in the universe cannot be created or destroyed, but it can be transformed from
one form to another form.
Energy is measured in Joules.
Few simple day-to-day examples for the Law are:
the energy of motion is converted into heat
energy by the help of frictional force in
order to stop the car.
b) Consider any engine, where we use some
fuel to run it. The fuel is a chemical and
it is converted into mechanical energy for
the engine to start and some amount is
dissipated as heat energy.
Energy is called, the ability to do work or cause change.
Work can also be defined as the transfer of energy.
When an animate or inanimate (living or nonliving) body is able to do work we say that it possesses energy. Energy of a body is its capacity to do work.
Workis done when a force moves an object a distance.
Energy (or work) is measured in joules.
Energy is needed for all types of work, it is even needed to power the human bodies needed to complete most work.
Kinetic and Potential Energy
1. Heat Energy- (also called Thermal Energy)–the total energy of the particles in an object
The heat energy of a substance is determined by how active its atoms and molecules are.
A hot object is one whose atoms and molecules are excited and show rapid movement. When these molecules and atoms are in the excited state, they take up a lot of space because they're moving around so fast.
A cooler object's molecules and atoms will be less excited and show less movement. When the atoms and molecules settle down, or cool down, they take up less space.
* When the thermal energy of an object increases, the object becomes warmer
EX. Sun, material that is burning, and electricity
2- Solar Energy- energy that comes from the sun.
Every day the sun radiates, or sends out, an enormous amount of energy. The sun radiates more energy in one second than people have used since the beginning of time!
Solar energy is the sun’s rays (solar radiation) that reach the Earth.
Solar energy can be converted into other forms of energy; such as heat and electricity.
3. Chemical Energy- stored in chemical compounds
It is the form of energy that is used most often.
Batteries that are powering our cell phones and television remotes use chemical energy to perform the functions we require.
The burning of fossil fuels also use chemical energy. When coal is burned to provide power all over the globe, or when gasoline is combusted in our automobiles, or even when natural gas is used to provide heating power in our homes, chemical energy is used.
Our bodies use chemical energy too!
* Chemical energy is potential energy stored in the chemical bonds that hold chemical compounds together.
4. Mechanical Energy- the energy associated with the motion or position of an object (think…can it move?)
An object that possesses mechanical energy is able to do work. In fact, mechanical energy is often defined as the ability to do work. Any object that possesses mechanical energy - whether it is in the form of potential energy or kinetic energy- is able to do work.
*Can be kinetic or potential
EX. Machine, falling water, human arm or leg
5. Electrical Energy- moving electrical charges that can be easily transformed into other forms of energy.
Electrical energy is the presence and flow of an electric charge.
EX. Battery & generator
What is an energy transformation? When energy changes from one form to another.
Energy Transformations can be from…
-potential to kinetic or kinetic to potential
- one type of energy
1. Potential to Kinetic –
Ex. Water behind a dam has potential energy. The potential energy of the water changes to kinetic energy when the water begins to move.
2. Kinetic to potential–
Ex. A rollercoaster moving up a hill has kinetic energy. When it reaches the top of the hill and pauses, it changes to potential energy.
Other Examples: swing,
3. Kinetic to sound –
Ex. When the movement, kinetic energy, of drumsticks strike the drum, it causes it to vibrate and changes to sound energy.
Other Examples: radio,
airplane, car, anything that
moves and makes a sound.
4. Kinetic to heat –
Ex. When the movement, kinetic energy, of electricity flows through the wall into the heater, it changes to heat energy.
tires on a road, motor,
5. Mechanical to electrical –
Ex. A generator transforms mechanical energy into electrical energy.
6. Solar to Potential –
Ex. When the energy from the sun, solar energy, is transferred into potential energy in a solar panel.
7. Solar to Chemical –
Ex. When plants go through photosynthesis they transform solar energy to chemical energy in the sugar that they produce.
8. Chemical to Mechanical –
Ex. When chemical energy is transferred into mechanical energy, such as eating food (chemical) and
using it to move (mechanical)
battery of a car, etc.
9. Chemical to Heat –
Ex. When chemical energy transfers into heat energy, such as the rocket full transferring into heat from
Other Examples: fire, our
10. Heat to Electrical –
Ex. The transfer from heat energy to electrical energy, such as in a turbine.
11. Electrical to Mechanical –
Ex. Mechanical motion can be produced in an electric circuit if a fan,
or other object, is added to
12. Electrical to sound –
Ex. Sound can be produced in an electric circuit if a bell, buzzer, radio, or TV is added to the circuit.
13. Electrical to Light –
Ex. Light can be produced in an electric circuit if a light bulb is added to the circuit.
14. Electrical to Heat –
Ex. Heat can be produced in an electric circuit if a toaster, stove, or heater is added to the electrical circuit