ENERGY forms, Transformations, resources

Forms of energy

Energy — the ability to cause change. Fireworks release energy when they explode. Causes changes you see as bursting flashes of light and hear as loud booms.

ALL moving objects have KE. Kinetic Energy (KE) — energy in the form of motion. ALL moving objects have KE. KE depends on mass and speed of moving object. Faster object moves, more KE it has Object with more mass, has more KE

Types of PE: Elastic PE Chemical PE Gravitational PE Potential Energy (PE) — energy that is stored due to interactions between objects or particles. Types of PE: Elastic PE Chemical PE Gravitational PE Elastic Potential Energy – energy stored by something that can stretch or compress, such as rubber band or spring.

Chemical Potential Energy (CPE) – energy stored in chemical bonds between atoms and released when chemical reactions occur. A glass of milk has CPE until you drink it then calories are used as energy for your body Gravitational Potential Energy (GPE) – Also Known As – height energy; energy related to gravitational force. Higher up the object is, the more GPE it has.

Work: transfer of energy that occurs when a force makes an object move in the direction of the force while the force is acting on the object. Transfer energy by doing work (girl lifts box onto shelf) Object that has energy can also do work (bowling ball does work on bowling pin)

Other Forms of Energy…. Mechanical Energy (ME) – The sum of PE and KE in system of objects (Example - ME of basketball increases when player shoots). Sound Energy (SE) – Energy that sound carries; vibrating objects emit SE, but can’t travel through vacuum such as space between Earth and Sun (Example – pluck guitar string). Thermal Energy (TE) – sum of KE and PE of the particles that make up an object. Due to atomic-scale motions and interactions of particles. Moves from warmer objects (burning logs) to cooler objects (air).

4. Electric Energy (EE) – energy an electric current carries (electrical appliances change electric energy into other forms of energy). 5. Radiant Energy/Light Energy (RE) – energy that electromagnetic waves carry; can travel through vacuum. 6. Nuclear Energy (NE) – energy that is stored and released in the nucleus of an atom.

Energy Transformations

Energy Changes…. Making popcorn in the microwave Microwave changes electric energy into radiant energy Radiant energy changes into thermal energy in the popcorn kernels. Changes from electric energy to radiant energy to thermal energy are called energy transformations.

Changes Between KE and PE (refer to page 148) Energy transformations occur when tossing a ball upward Ball slows down as it moves upward and speeds up as it moves downward Ball’s speed and height change as energy changes from one form to another

Total Energy = Sum of all the different forms of energy everywhere The Law of Conservation of Energy – energy may change form and it may be transformed from one form to another, but it cannot be created or destroyed under ordinary conditions. Total Energy = Sum of all the different forms of energy everywhere Amount of total energy in the universe DOES NOT change

But what about when….. What happens to the energy when you apply the brakes of a bicycle and come to a stop? The bicycle’s mechanical energy is not destroyed, but it transformed into thermal energy Total amount of energy NEVER changes Additional thermal energy causes brakes, wheels, and air around the bicycle to become slightly warmer Friction between bicycle’s brake pads and moving wheels transforms mechanical energy into thermal energy

Friction Always some friction between any two surfaces rubbing against each other Which means always some mechanical energy transformed into thermal energy Easier to pedal a bike with less friction (results in less mechanical energy being transformed into thermal energy) One way is to grease/oil the surfaces rubbing together

Using Thermal Energy ALL forms of energy can be transformed into TE Use to cook food or provide warmth In jet engine, burning fuel releases thermal energy that the engine transforms into mechanical energy Electric space heater transforms electric energy from power plant into thermal energy that warms a room Gas stove transforms chemical energy stored in natural gas into thermal energy that cooks food

Using Chemical Energy During photosynthesis, plant transforms Sun’s radiant energy into chemical energy. Some of compounds become food for other living things. Body transforms chemical energy from your food into kinetic energy necessary for movement. Body transforms chemical energy into thermal energy to keep you warm.

Using Radiant Energy Cell phones transform radiant energy into electric energy and then into sound energy When speaking on the cell phone, it is transforming sound energy into electric energy and then into radiant energy

Using Electric Energy Many devices (handheld video games, MP3 players, hair dryers) use electric energy. Handheld video games and MP3 players transform chemical energy stored in batteries into electric energy. Small appliances, like hair dryers, use electric energy from electric power plants.

Waste Energy When energy changes form, some thermal energy ALWAYS released Energy that can’t be used is called Waste Energy. Example – lightbulb converts some electric energy into radiant energy, but also transforms some electric energy into thermal energy (makes lightbulb hot). Some of TE moves into air and can’t be used.

Energy Resources

Sources of Energy Almost all of the energy you use can be traced back to the Sun Examples - Chemical energy in food from Sun Energy in fuels (gas, coal, wood) from Sun Amount of energy coming from Sun each day is about 5,000 times greater than amount of energy that comes from inside the Earth

Electric Power Plants Electric power plant transforms energy into electric energy. Three main energy sources used in power plants Most of the energy you use every day doesn’t come directly from the Sun. Most comes in form of electric energy from power plants. Burning fuels, such as coal Nuclear energy contained in uranium Falling water into electric energy at hydroelectric plants https://app.discoveryeducation.com/player/view/assetGuid/37fb4ab0-bbc0-4c50-b89c-50a1fd9ea645

NONRENEWABLE ENERGY RESOURCES

Nonrenewable Energy Resources Ex. - Coal that power plant burns Definition – an energy resource that is available in limited amounts or that is used faster than it is replaced in nature (red beans). Most commonly used nonrenewable energy resources are fossil fuels (remains of ancient organisms that can be burned as an energy source).

Fossil Fuels Takes millions of years to form Being used up faster than they form 3 types are: coal natural gas petroleum Formed from organisms that changed radiant energy from to chemical potential energy Chemical potential energy stored changes to thermal energy when fossil fuels burn

Using….. Petroleum: Gasoline, fuel oil, diesel, and kerosene made from petroleum. Burned mainly to power cars, trucks, planes and to heat buildings. Also used as raw material in making plastics. Coal: Electric power plants burn about 90% of coal in U.S. Used to heat buildings, to produce steel & concrete Burning produces more pollutants than burning others Can create acid rain by reacting with water vapor Natural Gas: ½ all homes in U.S. use natural gas for heating Electric power plants burn about 30% of the natural gas used in U.S. Produces less pollution than other fossil fuels

Global Warming Burning fossil fuels releases carbon dioxide gas into Earth’s atmosphere Carbon Dioxide is one of gases that helps keep Earth warm Over past 100 years, Earth has warmed by 0.7˚C or 33˚F Due to increasing amount of carbon dioxide produced by burning fossil fuels https://app.discoveryeducation.com/player/view/assetGuid/03eb8689-e052-476c-8692-09d3efa7c033

Nuclear Energy Humans can transform nuclear energy from uranium into thermal energy (uranium not being formed inside Earth, making it a nonrenewable energy source). Nuclear power plant doesn’t release pollutants into air, but does produce harmful nuclear waste which contains radioactive materials that damage living things. Remain radioactive for 1000s of years. Stored at nuclear power plant where produced.

RENEWABLE ENERGY RESOURCES

Most widely used renewable energy resource is falling water. Renewable Energy Resources Ex. – hydroelectric power plant Definition – an energy resource that is replaced as fast as, or faster than, it is used. Most widely used renewable energy resource is falling water.

Hydroelectric Power Plants To generate electric energy from falling water, a dam is built across a river, forming a reservoir. As water falls through tunnels in the dam, the water’s PE transforms into KE. Don’t emit pollutants Florida has 2: Tallahassee Apalachicola River on GA/FL border https://app.discoveryeducation.com/player/view/assetGuid/bd7f30f4-b0eb-4685-981c-90a0016ecb23

Solar Energy Solar Energy Radiant energy from Inexhaustible energy resource (energy resource that can’t be used up) Less than about 0.1% of energy used in U.S. comes directly from Converted directly into electric energy by solar cells (contain materials that transform radiant energy into electric energy when sunlight strikes solar cell) Example – Solar roof panels Largest collection of solar panels in SE part of U.S. is at the Orange County Convention Center

Wind Energy Inexhaustible energy resource Wind turbines convert KE into electric energy Produces no pollution Practical only where average wind speed is more than 5 m/s Need a huge area in order to be effective

Biomass Materials that come from plants or animals that are burned to keep people warm or to cook food. Examples include: wood, dried peat moss, manure. FL accounts for 7% of total U.S. biomass output (sugarcane, citrus, urban wood waste) Many universities conduct biomass research (how to use these resources as energy) Some is converted into fuels to burn in engines of cars (biofuels). Can reduce use of gasoline making supply of petroleum last longer

Geothermal Energy Thermal energy from inside Earth Comes from decay of radioactive nuclei deep inside Earth Produces underground pockets of hot water and steam called geothermal reservoirs Wells can be drilled to reach reservoirs

Conserving Energy Resources Fossil fuels provide 82% of energy used in Florida and the U.S. Fossil fuels are nonrenewable resources so supply is decreasing Must conserve energy (avoid wasting) Turn off lights Take shorter showers Close refrigerator door Can you list some ways to conserve energy?

TRANSCRIBE THE TABLE FROM PAGE 162 IN INTERACTIVE NOTEBOOK ON PAGE 48.