ENERGY – What is it?

1. ENERGY – What is it? WORK AND ENERGY

2. 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: • Stored (potential) energy • Working (kinetic) energy • Energy can also be found in a number of different forms. It can be chemical energy, electrical energy, heat (thermal energy), chemical energy, mechanical energy, and solar energy. • Energy describes the amount of work that can be performed by a force.

3. b. What is the Law of Conservation of Energy? 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: • when we apply brakes while driving a car, 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.

4. c. How are work and energy related? 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.

5. d. Kinetic and Potential Energy : • KINETIC ENERGY is the energy of motion. The kinetic energy of an object is the energy it possesses because of its motion. • POTENTIAL ENERGY is the energy which results from an object’s position. An object may have the capacity for doing work as a result of its position in a gravitational field (gravitational potential energy) and an electric field (electric potential energy). • There are two types of potential energy • Elastic potential energy-potential energy associated with objects that can be stretched or compressed • Gravitational potential energy- potential energy that depends on height Kinetic and Potential Energy

6. e. Types of 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

7. e. Types of Energy 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.

8. e. Types of Energy 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.

9. e. Types of Energy 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

10. e. Types of Energy 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

11. f. Energy transformations 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 OR - one type of energy

12. Examples of energy conversion 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. Other Examples: rollercoasters, fan, etc.

13. Examples of energy conversion 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, car, etc.

14. Examples of energy conversion 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.

15. Examples of energy conversion 4. Kinetic to heat – Ex. When the movement, kinetic energy, of electricity flows through the wall into the heater, it changes to heat energy. Other Examples: tires on a road, motor, etc.

16. Examples of energy conversion 5. Mechanical to electrical – Ex. A generator transforms mechanical energy into electrical energy.

17. Examples of energy conversion 6. Solar to Potential – Ex. When the energy from the sun, solar energy, is transferred into potential energy in a solar panel.

18. Examples of energy conversion 7. Solar to Chemical – Ex. When plants go through photosynthesis they transform solar energy to chemical energy in the sugar that they produce.

19. Examples of energy conversion 8. Chemical to Mechanical – Ex. When chemical energy is transferred into mechanical energy, such as eating food (chemical) and using it to move (mechanical) Other Examples: battery of a car, etc.

20. Examples of energy conversion 9. Chemical to Heat – Ex. When chemical energy transfers into heat energy, such as the rocket full transferring into heat from the fire. Other Examples: fire, our bodies, etc.

21. Examples of energy conversion 10. Heat to Electrical – Ex. The transfer from heat energy to electrical energy, such as in a turbine.

22. Examples of energy conversion 11. Electrical to Mechanical – Ex. Mechanical motion can be produced in an electric circuit if a fan, or other object, is added to the circuit.

23. Examples of energy conversion 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.

24. Examples of energy conversion 13. Electrical to Light – Ex. Light can be produced in an electric circuit if a light bulb is added to the circuit.

25. Examples of energy conversion 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