# Science 2024: Energy

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Science 2024: Energy

## 1. Generating electrical energy

### 1.1. Renewable vs Non-Renewable energy

1.1.1. Renewable

1.1.1.1. Energy that comes form natural sources that are constantly replenished and won’t run out

1.1.1.1.1. Example: Solar power - uses energy from the sun because it will keep shining for billions of years

1.1.2. Non-renewable

1.1.2.1. Energy that comes from sources that can be depleted and are not naturally replaced within a human timescale

1.1.2.1.1. Example: Coal - it’s formed from ancient plant materials which cannot be produced for millions of years and can be depleted

### 1.2. Generated energy

1.2.1. A generator converts kinetic energy into electrical energy by rotating a rotor within a magnetic field. This rotation induces an electric current in coils of wire. For example, in a wind turbine, the wind turns the blades, which drive the generator to produce electricity.

### 1.3. Methods of generating electricity

1.3.1. Word equations setup

1.3.1.1. Energy transformations: wind power: kinetic energy + electrical energy

1.3.1.3. Energy transformations = Word equations

## 3. 3 energy transmission/ heat transfer types

### 3.1. Conduction

3.1.1. - Heat transfer without movement - particles vibrate and transfer energy - heat moves from the hotter till the colder part till the equilibrium - most effective in solids where particles are dense

3.1.1.1. Example: When a metal spoon is placed in hot tea, heat transfers from the tea to the spoon, warming it along its length. This illustrates how conduction transfers heat through a solid material.

### 3.2. Convection

3.2.1. - Convection currents are heat driven and go in a circular motion - Happens in the air, ocean and mantle (earths materials) - Difference in temperature due to differing heat sources

3.2.1.1. Example: When heating a pot of water, the water at the bottom warms up, becomes less dense, and rises, while cooler, denser water sinks. This creates convection currents that distribute heat evenly throughout the water.

3.3.1. - energy that travels as waves or particles - It can move through empty space (it doesn’t need material to move through)

3.3.1.1. Example: Sunlight is radiation energy that travels from the sun to earth

3.3.1.2. Example: foil for a roast chicken, keeping it warm

3.3.1.3. Example: thermal blanket that retains heat through it’s insulating and reflective properties that produces heat energy

### 3.4. Conductors vs Insulators

3.4.1. Conductors

3.4.1.1. Conductors are materials that easily allow heat or electricity to pass through them. This is because they have free-moving particles, like electrons, which can carry energy quickly.

3.4.1.1.1. Metal cookware/cutlery - eg. Cooking things in a pot on a stove/ putting a hot spoon in a drink and it absorbs the heat

3.4.2. Insulators

3.4.2.1. Insulators are materials that do not allow heat or electricity to pass through them easily. Their particles are very dense, so energy doesn’t transfer well.

3.4.2.1.1. Rubber gloves - electricians wear rubber gloves to prevent themselves from being electric shocked but insulating against electricity

## 4. Types of energy

### 4.1. Active energy (in action)

4.1.1. Sound energy (vibration)

4.1.2. Heat/thermal energy

4.1.3. Kinetic energy (movement)

4.1.4. Light energy (glowing/luminous objects)

### 4.2. Potential energy (stored energy)

4.2.1. Gravitational potential energy

4.2.1.1. An apple hanging from a tree, a plane flying overhead

4.2.2. Elastic potential energy

4.2.3. Magnetic potential energy

4.2.3.1. Loudspeakers,

4.2.4. Nuclear potential energy

4.2.4.1. The sun, smoke detectors, geothermal energy

4.2.5. Chemical potential energy

4.2.5.1. Eg. food, fuel, chemical substances

## 5. Energy conservation law

### 5.2. Energy cannot be created or destroyed but it can transform into a different type of energy/ or it can transfer from one object to another

5.2.1. Ex 1:A battery operated torch used chemical potential energy thats stored in a battery which is then converted into active energy and potential energy

5.2.1.1. Equation: chemical potential energy -> light energy + thermal energy

5.2.2. Ex 2: A cup of hot chocolate has more heat energy than my hand. Hence, some of the heat energy will transfer to my hand until it eventually reaches the thermal equilibrium

## 6. Energy Efficiency

### 6.3. FACT: The reactant and primary product are efficient. Whereas, the secondary products aren’t efficient and considered as “waste energy”

6.3.1. Example: electrical energy → HEAT ENERGY (primary) + sound + light energy (secondary)