Different Energy Stores

The 3 ways Energy can be transferred

1. Mechanically⚙: Energy is transferred when a force causes an object to move. For example, pushing a box across the floor transfers energy mechanically, as work is done on the box to move it.

2. Electrically⚡: Energy is transferred when an electric current flows through a circuit. For instance, when you plug in an appliance, electrical energy is transferred from the power source to the device, allowing it to function.

3. By Heating🔥: Energy transfer through thermal interactions, which includes conduction 💥(through direct contact), convection💧(through fluid movement), and radiation ☢(through electromagnetic waves e.g light). Heating transfers energy due to temperature differences between objects or regions within a material.

Drawing Energy Store Diagrams

Power + Work Done

1. What Is Work Done?

• Work is done when a force causes an object to move in the direction of the force.

• Because a force is necessary only 2 of the 3 methods of energy transfer Mechanically⚙ and Electrically⚡are possible with Work done pop

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2. Formula for Work Done

• Work Done (W) = F × d

  • W is work done (measured in joules, J and Newton meters, Nm).

  • 1 joule = 1 newton-meter

  • F is the force applied (in newtons, N).

  • d is the distance moved by the object in the direction of the force (in meters, m).

3. Work Done Requirements

• If there’s no movement: if you apply a force but the object still doesn’t move, no work is done.

• Direction matters: Only the component of force in the direction of movement contributes to work.

  • If the force is perpendicular to the direction of motion (like carrying a box horizontally while gravity acts downward), no work is done by that force in the direction of motion.

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4. Power

Power is Measured In Watts (W)

Energy Transferred is measured in Joules (J)

Time Taken to Transfer that energy is measured in seconds (sec)

Example

Fossil Fuels

1. What Are Fossil Fuels?

• Fossil fuels are natural energy sources formed from the remains of ancient plants and animals being compressed in the Earth over millions of years.

• The main types are coal, oil, and natural gas.

• Fossil fuels are rich in carbon and hydrocarbons (compounds of hydrogen and carbon).

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2. Formation of Fossil Fuels

• Fossil fuels form through a process called carbonization:

  1. Organic matter (plants and tiny sea creatures) are buried under layers of sediment.

  2. Heat and pressure from overlying layers transform the organic matter.

  3. Over millions of years, chemical reactions convert this matter into coal, oil, or natural gas, depending on the type of organic matter, temperature, pressure, and geological conditions.

3. Chemical Energy in Fossil Fuels

• Fossil fuels store chemical energy within the bonds of hydrocarbon molecules.

• This energy originates from solar energy absorbed by ancient plants through photosynthesis.

• During photosynthesis, plants used sunlight to convert carbon dioxide and water into organic molecules, storing solar energy in the chemical bonds.

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4. Combustion Of Fossil Fuels

• Combustion is the process of burning fossil fuels to release stored chemical energy.

• Energy Released: The fuel is burnt within a fossil fuel burning plant. When the fuel is burnt, the chemical energy in the fuel is converted into thermal energy. The thermal energy is then used to heat up water, which is boiled, creating steam. The thermal energy is converted to kinetic energy as the rising steam is used to spin a turbine. The kinetic energy in the turbine generates electrical energy in the generator, which is used to heat water. And the required electricity is then created.

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• In power plants, the heat from burning fossil fuels is used to boil water.

• This creates steam that spins turbines connected to electrical generators.

• Turbine and Generator System:

  • Turbines convert kinetic energy from the steam into mechanical energy.

  • Generators then convert mechanical energy into electrical energy using electromagnetic induction (where moving a conductor through a magnetic field generates current).

• Fossil fuels have high energy density, meaning they store a large amount of energy per unit of mass or volume.

• Energy Density Comparison:

  • Coal: Roughly 24 MJ/kg

  • Oil: About 42-47 MJ/kg

  • Natural Gas: Around 55 MJ/kg

• This high energy density makes fossil fuels efficient for powering vehicles, factories, and electricity generation.

5. Efficiency and Heat Loss

• Energy Conversion Efficiency: Only a portion of the energy in fossil fuels is converted into useful work

• Heat Loss: Combustion processes can lose energy as heat to the surroundings, so most systems are 30-40% efficient.

6. Pros and Cons of Fossil Fuels

Pros

Their reliable

Cons

7. Alternatives to Fossil Fuels

Fossil fuel alternatives are increasingly crucial in addressing climate change, reducing pollution, and promoting sustainable energy. Here are some of the most promising and widely used alternatives:

Nuclear Energy

The main nuclear fuels are uranium and plutonium.

inside the reactor, neutrons split uranium atoms, and that makes more neutrons. They split more atoms, and we have more neutrons, and on and on and on. This is called a chain  reaction, and it produces a load of heat. 

• this heat is used to change water into steam in the boiler;

• the steam drives the turbine (heat to kinetic energy);

• this drives the generator to produce electricity - kinetic to electrical energy.

Nuclear and geothermal energy are the only energy resources that do not come from the Sun.

Advantages

• Unlike fossil fuels, nuclear fuels do not emit greenhouse gases such as carbon dioxide.

• Cheaper to run once built

• Conserves Fossil Fuels

• Safe Under Normal Conditions

• Nuclear fuels do not emit gasses such as sulphur dioxide which cause acid rain.

• 1 kg of nuclear fuel produces millions of times more energy than 1 kg of coal.

Disadvantages

• Like fossil fuels, nuclear fuels used for fission, such as uranium ore, are non-renewable energy resources since supplies will not last forever.

• Although modern reactor designs are extremely safe, their is still a risk of disaster in which, large amounts of radioactive material could be released into the environment.

• Nuclear waste remains radioactive and is hazardous to health for thousands of years, so it must be stored safely.

• can cause cancer

• Expensive to build

• Decommissioning a nuclear power plant is extremely expensive.

Chernobyl

The Chernobyl disaster began on 26 April 1986 with the explosion of the No. 4 reactor of the Chernobyl Nuclear Power Plant

The Chain Reaction Has to be Controlled Otherwise it keeps growing like in a nuclear bomb

Metal Rods Are inserted into the reactor to control the speed of the chain reaction

But to much Radioactive material builds up and blows the roof of the Chernobyl reactor spewing radioactive material everywhere

This turned Chernobyl into a wasteland filled with dangerously high amount of radiation

radiation is invisible - you can’t see, smell or hear it