Energy Work and Power

Conservation of Matter

• Matter cannot be created or destroyed.• Atoms and particles can be rearranged.

Conservation of Energy

• Energy can never increase or decrease.• Energy can change from one form to another.• But the total amount of energy in the universe

remains the same.• energy is that it is constantly being changed

and recycled from one form to another

ENERGY AS WORK

• Energy is work or the capacity to perform work

• Work is when a force is applied to an object so that it moves a distance.

W = Fx

• W – work – in Joules (J)• F – force – in Newtons (N)• x – distance moved – in meters (m)

KINETIC AND POTENTIAL ENERGY

• Energy of any matter in motion is termed kinetic energy.

• Potential energy is called "the energy of position."

ELECTROMAGNETISM

• every atom is held together by positive and negative electrical charges

• a form of electromagnetic energy• The energy from our sun is transmitted to the

Earth via electromagnetic waves

NUCLEAR ENERGY

• strong nuclear force holds the protons and neutrons together

• at the core of the sun, atoms fuse and in the process release energy

• process is called fusion.

NUCLEAR ENERGY

• the energy from a nuclear bomb, and from nuclear reactors released by the splitting apart of the nucleus of atoms

• This is called fission.

CHEMICAL ENERGY

• The source of all energy for all living things is in a chemical process called photosynthesis.

• electromagnetic waves provide the energy to convert water, and carbon dioxide from the air, into oxygen and glucose

• Glucose is used as energy by the plant and animals that the eat the plant

• Advantage of chemical energy is it can be stored as potential energy for long periods of time and then released as kinetic energy

SOUND ENERGY

• sound is a form of kinetic energy• sound energy radiates outwards, transmitted

from molecule to molecule• Is there sound in space?

THE ENERGY OF HEAT

• Heat is a form of kinetic energy• rapid movement of molecules• As the heat of an object increases, the

molecules move more and more rapidly.

ENERGY EXCHANGES

• Heat is a by-product of the mechanical or chemical processes

THE THREE LAWS OF THERMODYNAMICS

1. energy cannot be created or destroyed2. all things are moving towards equilibrium3. as a system approaches absolute zero, the

extraction of energy becomes more and more difficult

THE ENERGY-MATTER CONNECTION

• Albert Einstein• E = mc²– Energy (E) equals mass, (m) times the speed of

light squared (c².)

• matter can be transformed into pure energy

Video Quiz

1. Energy can be created and sometimes destroyed. F

2. The formula physicists use to express the expenditure of work or energy is W=Fx .

3. Kinetic energy is described as energy of matter in motion. T

4. Potential energy is not important in the total amount of energy available in the universe. F

5. Electromagnetic energy only exists as radiant energy from the sun and stars. F

6. Under intense heat two hydrogen atoms will fuse to form a helium atom and release energy. This process is called FUSION.

7. Photosynthesis is a process that converts energy from the sun into chemical energy in the leaves of plants. T

8. Energy can be changed and recycled from one form to another. T

9. The second law of thermodynamics concludes that all things are moving towards EQUILIBRIUM.

10. Einstein's formula of E = mc² states that energy equals mass times the speed of light squared. T