Science Energy

What is energy?

Energy is the ability to do work. There are two states of energy: potential energy, or energy at rest/stored en energy, and kinetic energy, or energy in motion (doing work).

Energy

the ability to do work or cause change (unit = Joules - J)

All matter is made up of particles called

atoms

these particles never stop moving

their movement is energy

The Law of conservation of energy

• energy cannot be created or destroyed

• it can be transferred or transformed

• the amount of total energy stays constant

• this is also called the first law of therodynamics

The Law of entropy

• when energy transforms, the amount on energy remains the same, but its ability to do work decreases

• meaning a system is never 100% efficient at providing the anticipated outcome

• this is also called the second law of therodynamics

Basic Forms of energy

potential energy - static energy, graviational energy, nuclear energy, elastic energy, and chemical energy

kinetic energy - sound energy, electric currents, thermal energy, mechanical energy, and light energy

Static energy

• a build up of electrical charges (ions) on a surface

• is electric current when it is a spark or shock

Gravitational energy

• energy due to an objects height

• higher an object is the more potential energy

• more mass an object has the more potential energy

Nuclear energy

• its in the nuclei of atoms

• energy is released when atoms split of fuze

• fission is the splitting of nuclei of heavy atoms(nuclear power)

• fusion is the combining of nuclei of light atoms (the sun)

Elastic energy

• any object that is stretched or compressed

Chemical energy

• bonds holding atoms of molecules together

• released when the bonds are broken

Sound Energy

• sound waves are vibrations through air or water

• measuring in decibels (dB) - sound intensity, and hertz (Hz) - sound frequency

Electric energy

• a current of moving electrons on a path to positive and negative through a conductor

Thermal energy

• energy of moving atoms

• faster vibration - more heat

• temperature - average movement of atoms

• tool is the thermometer

• cold is not a type of energy, but an absent of thermal energy

Mechanical energy

any object in motion

Light energy

• atoms absorb energy and release it as electromagnetic radiation

• travels in waves, similar to sound

potential energy

PE = m*g*h (unit is J)

m= mass (kg)
g= gravite (9.8 m/s²)

h= height of object (m)

Kinetic energy

KE = 0.5(m*v²) (unit is J)

m= mass (kg)

v= velocity (m/s)

Energy as power

• efficient appliance - machine that uses less energy than others

• clean energy - energy that produces little or no pollution carbon emissions

• renewable - energy that is infinite; can be reused and wont run out

• non-renewable - energy that is finite and will take millions of years to be replaced

• fossil fuels - certain types of non-renewable energy that creates carbon dioxide emissions and adds to global warming