[5] Energy

What are the 8 different stores of energy

gravitational potential energy
kinetic energy
thermal
elastic potential energy
chemical
nuclear
magnetic
electrostatic

4 ways energy can be transferred

radiation (light and sound)
heat
mechanical
electrical

what is the definition of energy

the ability to work

what is conservation of energy

energy cannot be created or destroyed; it can only be transferred or transformed from one form to another.

how is energy transferred in a falling object like a ball

A falling object converts its gravitational potential energy into kinetic energy as it falls.

What types of energy are involved in a rollercoaster ride?

At the top, the rollercoaster has maximum gravitational potential energy.

As it descends, potential energy is converted into kinetic energy.

At the bottom, it has maximum kinetic energy and minimum potential energy.

What is the formula for efficiency?

Efficiency = Useful Energy Output/ Total Energy Input ×100

What are the common energy losses in a system?

Heat energy

Sound energy

equation linking work done, force and distance moved in the direction of the force

W = Fd

GPE equation

GPE = mgh

KE equation

½ mv²

equation linking GPE and KE (ONLY USED WHEN ENERGY DOES NOT GET LOSE/CHANGED)

v = square root 2gh

what is conduction

when heat is transferred through a solid. the heat is passed on by vibrations in the molecules.

why are metals better conductors than non metals

metals contain delocalised electrons, when a potential difference is applied, these free electrons move and transfer energy quickly, allowing electrical current to flow easily.

what is convection

when a gas or liquid moves and carries heat with it.

what happens to a fluid when it is heated

it expands which means the warmer liquid will become less dense than the colder fluid around and the warmer fluid will try to float and rise over the cooler fluid will sink

what does warm air do?

rises

how does heat reach us from radiators

Heat is transferred through convection, where the radiator warms the air around it, causing the air to become less dense and rise.

what is radiation

when heat moves around in electromagnetic waves like light does.

what do hot objects emit, what is it called and what can it cause?

hot objects will emit radiation which is called infra-red too much of it will cause sun burn.

what do dark, matt colours do?

dark, matt colours will absorb and emit the most infra-red radiation

what do light, shiny colours do

reflect infra-red radiation

where does radiation happen give an example?

through an empty space for example this is how we get heat from the sun

what is a leslie’s cube and what are they used? [2]

hollow metal cube made of 4 different colours and materials on each faces/surfaces used to see how effective different colours and materials are at absorbing radiation

Describe an experiment that could be done with the cube to  

discover what surface is the best at transmitting radiation. use bullet points (6 marks)

-fill cube with hot water
-measure water temperature
-leave for a period of time
-measure the 4 surfaces using an infra red thermometer
- repeat the experiment
-find the average for each individual surface

dangers of experiment discovering what surface is the best at transmitting radiation [2]

-warm water may burn
-electric shock due to water spills

equation linking power energy and time

P = E/t

How does insulation help reduce unwanted energy transfers?

slows down the rate of heat transfer, preventing heat from escaping in cold environments or entering in hot environments.

What are some materials commonly used as insulators?

plastic, wood, polystyrene and air

what are some materials commonly used as conductors

metals like silver, copper, gold, aluminum, and steel

How does reflective foil help in reducing unwanted energy transfers?

reflect heat back into the room, reducing the amount of heat lost through the walls and improving the efficiency

Why is reducing unwanted energy transfers important in everyday life?

It helps in saving energy and reducing costs making homes and buildings more energy-efficient and environmentally friendly by lowering carbon emissions.

examples of non renewable energy sources and how they work

coal oil and gas by burning fossil fuels

3 examples of renewable energy sources and how they work

sun through solar cells
wind through wind turbines
hydroelectric through dams which trap water

why do we use fossil fuels

they are very reliable and have a high energy density

what are fossil fuels

decaying life

describe energy stores and transfers for fossil fuels

chemical energy in fuel is transferred by heating into thermal energy in water which is transferred mechanically into kinetic energy in turbines which is electrically transferred to whatever is needed

describe energy stores and transfers for nuclear energy

nuclear energy in fuel is transferred by heating into thermal energy in water which is transferred mechanically into kinetic energy in turbines which is electrically transferred to whatever is needed

describe energy stores and transfers for geothermal energy

thermal energy in earth transferred by heating into thermal energy in water which is transferred mechanically into kinetic energy in turbines which is electrically transferred to whatever is needed

describe energy stores and transfers for hydroelectric energy

gravitational potential energy of water in dams is mechanically transferred to kinetic energy of the water which is mechanically transferred to kinetic energy in turbine which is electrically transferred to whatever it is needed for

describe energy stores and transfers for solar energy

light energy from sun is transferred by radiation to electrostatic energy in photo cells which is electrically transferred to whatever is needed

What is an advantage of solar energy?

Solar energy is renewable and sustainable. It produces no greenhouse gas emissions

What is a disadvantage of solar energy?

not continuous and depends on weather conditions

What is an advantage of wind energy?

Wind energy is renewable and does not produce emissions

What is a disadvantage of wind energy?

Wind energy is not continous and depends on wind conditions

What is an advantage of hydroelectric energy?

reliable, renewable, and provides consistent power

What is a disadvantage of hydroelectric energy?

negative environmental impacts like disrupting ecosystems and affecting water quality

What is an advantage of geothermal energy?

Geothermal energy is a sustainable and reliable energy source

What is a disadvantage of geothermal energy?

can only be used effectively in certain areas e.g. areas with volcanic activity

What is an advantage of nuclear energy?

highly efficient source of energy and does not release greenhouse gases

What is a disadvantage of nuclear energy?

produces radioactive waste, risk of nuclear accidents and expensive.

What is an advantage of fossil fuels