Energy

• Energy conversion – when a form of energy is changed to another form of energy

• Energy – ability to do work

• Kinetic energy – energy in motion

• Faster an object is moving the greater the kinetic energy, also the more mass an object has the greater the kinetic energy

• Potential – energy due to the objects position (object could move)

• Gravitational potential energy – energy against the force of gravity—lifted objects have GPE

• Mechanical energy – Has both kinetic + potential

• Law of conservation of energy – energy cannot be created or destroyed but can be changed from one form to another

• Energy efficiency – the amount of useful energy after a conversion – the more efficient the more energy that can be used

• Ex: shape of car, shape of plane, houses, windows

• Thermal energy – all the kinetic energy due to motion of particles that make up the object (faster the particles move the greater the thermal energy)

• Chemical energy – energy of a compound that changes as its atoms are rearranged, a form of potential energy

• Electrical energy – energy of moving electrons, a form of potential energy since motion only happens when object is connected to actual output

• Sound energy – vibrating object transmit energy through matter (S-L-G)

• Light energy – vibration of electrically charged particles, doesn’t need to be carried through matter, can travel in a vacuum (area with no matter-- SPACE)

Alternative Energy Sources

• Solar energy – energy from the sun, • Hydroelectric (water) – energy from

falling/moving water• Wind energy – energy from the heating of

earth surface• Geothermal – energy from the heating of

earth’s core• Biomass – energy produced from plants,

renewable

Energy resource Advantage Disadvantage

Fossil Fuels (petroleum, coal, natural gas)

Easy transport, large thermal energy per unit

Nonrenewable, pollution, produces acid rain

Nuclear Large amount of energy, no pollution

Radioactive waste, elements are nonrenewable

Solar Limitless, no pollution Expensive, practical only in sunny areas

Hydroelectric Water is renewable, no pollution

Disrupts ecosystems, only where moving water

Wind Limitless, inexpensive, no pollution

Only where wind blows consistently

Geothermal Limitless, little land required to build

Practical in hot spots, produces waste water

Biomass Renewable Pollution, requires large farm land

• Nuclear energy – energy from the change in the nucleus of an atom

• Nuclear fusion – the joining of atoms (H)

• Ex: when hydrogen is fused together at very high speeds to form helium (stars are nuclear reactors on a massive scale), the process releases tremendous amounts of energy

• Nuclear fission – the splitting of an atom

• Ex: when uranium is split, the potential energy in the nucleus is given off and used in nuclear power plants to generate electrical energy

• Electrical – can be changed into thermal,

sound, light and kinetic energy (most common energy used)

• Energy conversions allow us to maintain our daily lives through machines

• Conversion of energy always creates a certain amount of thermal energy for the transition to take place

• Chemcial:

• Photosynthesis – light energy to chemical energy

• 6CO2 + 6H2O + light energy → C6H12O6 + 6O2

• Cellular respiration – humans turning food (chemicals) into energy

• C6H12O6 + 6O2 → 6CO2 + 6H2O + ATP (energy)

• Nonrenewable resource – a resource that cannot be replaced in a reasonable amount of time

• Fossil fuels – (contains chemical energy)– Coal – buried dead plants– Petroleum/natural gas - animals

that were buried millions of years ago

• 3 most common types of fossil fuels are:– Coal – used to produce electrical energy by

power plants – Petroleum – used to run cars and create

other petrochemical products (plastics), Natural Gas – heat homes and buildings