Energy and its Forms (PDF)

1. What is Energy? Energy: The capacity to do work. Energy enables systems to perform tasks and cause changes to the environment. Work: The action of transferring energy to cause an object to move or change. Energy can exist in different forms and can be stored for later...

1. What is Energy? Energy: The capacity to do work. Energy enables systems to perform tasks and cause changes to the environment. Work: The action of transferring energy to cause an object to move or change. Energy can exist in different forms and can be stored for later use. Energy cannot be created or destroyed. It can only change form, as stated by the law of conservation of energy. 2. Forms of Energy Energy can be categorized into two main types: Potential Energy (Stored energy, waiting to be released): o Chemical Energy: Stored in chemical bonds, e.g., food, fuels (gas, petrol, etc.), and batteries. o Mechanical Energy: Stored in objects when they are stretched, compressed, or moved to a higher position, e.g., a compressed spring or water in a dam. o Nuclear Energy: Stored in the nucleus of atoms, released in nuclear reactions (used in nuclear power stations). o Gravitational Energy: Energy stored in objects lifted above the ground, e.g., a ball held in the air, a raised water reservoir in a hydroelectric power station. Kinetic Energy (Energy of motion): o Movement: Any object in motion has kinetic energy. This includes moving cars, flowing water, or a flying bird. o Electricity: The movement of electrons through a conductor. o Heat: The movement of particles within substances. o Sound: Vibrations of air particles that travel as sound waves. o Light: Electromagnetic waves that travel through space, like sunlight or light from a bulb. 3. Potential Energy Definition: Energy stored in objects that are not in motion but have the potential to move when released. Examples of Potential Energy: o Water in a reservoir (Hydroelectric power plants): Stored energy when water is elevated, which can later be converted to kinetic energy to generate electricity. o Pressure in a fire extinguisher: The compressed gas inside is potential energy that can be released to extinguish fire. o Elastic potential energy: Energy stored in compressed or stretched materials, such as a stretched rubber band or spring. Other forms: o A boulder at the top of a hill. o A bowstring drawn back before releasing an arrow. 4. Kinetic Energy Definition: Energy that an object has due to its motion. The faster the object moves, the more kinetic energy it possesses. Examples of Kinetic Energy: o Electricity traveling through a circuit: Electrons move along wires to power devices. o Heat energy: Atoms or molecules in substances vibrate more as they gain kinetic energy. o Sound: Vibrations traveling through air or other media. o Light: Waves of energy that travel through space. o Atoms vibrating: Heat causes molecules and atoms in a substance to vibrate, which is an example of kinetic energy at a microscopic level. Energy Transformation: Energy can change from potential to kinetic, such as when a ball is dropped, and potential energy is converted to kinetic energy. 5. Energy Storage Methods Energy can be stored in various ways, depending on the type of energy and its application.  Mechanical Energy Storage: o Compression: Storing energy by compressing a gas or material. E.g., in a spring or a gas-filled canister. o Tension: Energy stored by stretching materials like rubber bands or springs. o Motion: Energy stored through movement, like a flywheel that stores kinetic energy through rotation. Chemical Energy Storage: o Batteries: Store energy chemically, which can later be converted into electrical energy. Examples include rechargeable and non-rechargeable batteries. o Gases: Compressed air or natural gas can store energy that can be used later in various systems, like pneumatic tools. o Solid Fuel: Coal, wood, and other fuels store chemical energy that is released through combustion. o Food: Organic material stores chemical energy, which is converted to kinetic energy in our bodies. 6. Pneumatics Pneumatics: The use of compressed air or gas to perform work. o How it works: Air or gas is stored under pressure and released to produce movement, such as pushing a piston. o Applications: Common in industrial machinery, automated production lines, and tools like drills and hammers. o Advantages: ▪ Low maintenance. ▪ Accurate control of movement. ▪ Lightweight and versatile. o Example: Pneumatic drills, conveyor belts in factories. o Pump: A pump compresses the air or gas, creating the pressure needed for movement. 7. Hydraulics Hydraulics: The use of pressurized liquids (usually oil) to create force and perform work.  o How it works: Liquid is pumped into a system, creating pressure that can move heavy objects or perform precise tasks. o Advantages: Hydraulics provide more power and precision than pneumatics. o Applications: ▪ Lifting equipment: Hydraulic lifts in car repair shops. ▪ Car brakes: Hydraulic braking systems for smooth and effective stopping. ▪ Firefighting: Hydraulic tools are used to cut through debris during rescue operations. 8. Kinetic Pumped Storage Hydroelectric Power: Water is stored at a higher elevation, giving it potential energy. When there is an excess of electricity, water is pumped back up into the reservoir. Energy Conversion: When demand for electricity is high, the water is released to turn turbines, converting potential energy into kinetic energy to generate electricity. Advantages: This method provides a reliable, controllable supply of power, especially during peak demand. 9. Flywheel Energy Storage Flywheels: A mechanical device that stores kinetic energy in the form of rotational motion. o How it works: Flywheels rotate at high speeds, and energy is stored as rotational energy. When energy is needed, the flywheel slows down, releasing the stored energy. o Applications: ▪ Kinetic Energy Recovery Systems (KERS) in vehicles to save fuel and store energy during braking. ▪ Renewable energy: Flywheels help smooth energy delivery by storing surplus energy during high production and releasing it when production is low. 10. Chemical Energy Storage Batteries: Store energy through electrochemical reactions. o Non-rechargeable: Once the chemical energy is used up, the battery is disposed of. o Rechargeable: Can be used multiple times before losing capacity, e.g., lithium-ion batteries. Other Chemical Energy Storage: o Gas canisters: Store energy in compressed gases, used in various industrial and consumer applications. o Flammable gels: Petrol, diesel, and other fuels store significant chemical energy. o Hydrogen Fuel Cells: Store energy in hydrogen and convert it into electricity when needed. 11. Cells and Batteries Batteries consist of cells. Each cell has: o A positive terminal (cathode). o A negative terminal (anode). o Electrolytes that allow ions to flow. A 9V PP3 battery contains 6 cells (1.5V each). Voltage is the energy per charge (V = energy/charge). Current is the flow of charge. 12. Alkaline Batteries Advantages: Higher capacity, efficient, long-lasting, and better at holding charge compared to traditional lead-acid batteries. Miniaturization: Alkaline batteries have enabled the development of smaller, more portable electronic devices like smartphones and laptops. Usage: Common in household devices like remote controls, cameras, and clocks. 13. Rechargeable Batteries Increasing use in: o Portable appliances (e.g., vacuums, power tools). o Personal transport (e.g., electric scooters, e-bikes). o Hybrid/electric vehicles. o Mobile devices (e.g., phones, laptops). Environmental and Financial Impact: Rechargeable batteries are more sustainable as they reduce waste. However, the technology's lifespan and performance may degrade over time. 14. Emerging Battery Technologies Flow Batteries: Large systems that store energy in liquid form, typically used for large-scale energy storage. o Application: Smooths out energy demand for national grids. Sodium and Glass Batteries: High-capacity, ultra-fast-charging batteries. o Impact: Could revolutionize transportation by enabling faster charging times for electric vehicles. 15. Disposal of Batteries Environmental Concerns: Batteries contain toxic chemicals (e.g., mercury, cadmium) that can leach into the soil and water, harming wildlife. Safe Disposal: Batteries should be recycled at specialized centers to avoid environmental damage. 16. Plenary Questions 1. How can energy be stored? a. In mechanical, chemical, and electrical forms. 2. Difference between pneumatic and hydraulic systems? a. Pneumatics use compressed air, while hydraulics use compressed liquid for more powerful systems. 3. How can unpredictable energy generation be balanced?  a. By using energy storage systems like pumped storage, flywheels, and batteries to release energy when needed. 1. Where Does Our Energy Come From? Energy Sources: Energy is generated from a variety of sources, both renewable and non-renewable. Some of the key sources include: o Fossil Fuels: Coal, oil, natural gas. o Renewable Energy Sources: Wind, solar, tidal, hydroelectric, biomass. o Nuclear Power: Uranium and other radioactive materials. How is power generated from these sources? Each energy source has a specific method of power generation, which involves converting the energy into electricity, often via turbines or other mechanical systems. 2. Fossil Fuels Formation: Fossil fuels are formed over millions of years from the remains of ancient plants and animals. Through heat and pressure, these remains transform into coal, oil, or natural gas. Extraction: Fossil fuels are extracted through mining (coal) or drilling (oil and gas). Why are fossil fuels considered a finite resource? Fossil fuels are non-renewable. Once they are extracted and used, they cannot be replaced in a human timescale. Their formation took millions of years, so their supply is limited. Why are fossil fuels so relied upon for power generation? Fossil fuels are highly efficient at generating large amounts of energy. They are easy to transport and store. Fossil fuel plants are well-established and provide reliable power. 3. Energy Generation from Fossil Fuels Fossil fuels are burned to superheat water, which turns to steam under pressure. The steam drives turbines that generate electricity. How is energy from fuel converted to electricity? Fuel combustion heats water to produce steam. The steam spins a turbine, which is connected to a generator that converts mechanical energy into electrical energy. 4. What is Fracking? Fracking (Hydraulic Fracturing) is the process of drilling into shale rock to extract natural gas or oil. Water, sand, and chemicals are injected at high pressure into the rock to release trapped gas. What could go wrong with fracking? Potential for groundwater contamination due to chemical leakage. Earthquakes caused by changes in the Earth's crust. Air pollution and the release of methane, a potent greenhouse gas. 5. Renewable Energy Sources Renewable sources are classified as those that can be replenished naturally over time, and they don't deplete the Earth’s resources. They include: o Wind o Solar o Tidal o Biomass o Hydroelectric Why are these classified as ‘renewable’?  These energy sources are continuously available or can regenerate naturally, unlike fossil fuels which take millions of years to form. 6. Wind Turbines Wind power harnesses the movement of air to generate electricity. How it works: Wind turns the blades of a turbine, which are connected to a generator to produce electricity. Arguments for wind power: Renewable and does not produce greenhouse gases during operation. Low operating costs once installed. Provides local energy production, reducing reliance on fossil fuels. Arguments against wind power: Intermittent: Wind doesn't blow consistently, making it less reliable. Aesthetic concerns: Some people find wind turbines unsightly. Noise pollution: Turbines can be noisy, disturbing local communities. Land use: Large areas may be required to install wind farms. Would you want a turbine constructed beside your house? This depends on individual preferences and whether the environmental benefits outweigh the potential downsides (e.g., noise and aesthetics). 7. Solar Energy Solar Power: The Sun provides a constant stream of energy in the form of light and heat. How Solar Power Works: Photovoltaic (PV) cells convert sunlight into electricity. o When sunlight hits a PV cell, photons from the light allow electrons in the material to flow, creating an electric current. Advantages: Renewable and abundant. Low operating costs. Can be used for remote locations without connection to the grid. Disadvantages: Intermittent: Solar power depends on sunlight, so it’s only available during the day and can be affected by weather conditions. High initial costs for installation. Space: Large areas may be needed for solar farms. 8. Tidal Energy Tidal Power harnesses the movement of the tides to generate electricity. o The rise and fall of tides forces water through turbines, generating power. Advantages: Predictable: Tides are consistent and can be forecasted. Low environmental impact once built. Disadvantages: High construction costs due to the need for specialized infrastructure. Can disrupt marine ecosystems. Limited locations: Only certain coastal areas are suitable. 9. Hydroelectric Power (HEP) Hydroelectric power uses the energy from flowing water to generate electricity. o How it works: Water is stored in a reservoir behind a dam. When released, it flows through turbines that generate electricity. Advantages: Reliable and provides a steady supply of electricity.  No direct emissions of greenhouse gases during operation. Disadvantages: High setup costs and environmental impact. Flooding of vast areas to create reservoirs can displace communities and wildlife. Affected by local geography, as it requires specific river systems. 10. Biofuel and Biomass Biofuels and biomass are derived from organic materials, such as food and farm waste, compost, and wood. o These materials are burned or processed to generate energy. Why is biomass considered carbon neutral? Biomass is considered carbon neutral because the carbon dioxide released during combustion is offset by the carbon absorbed by the plants during their growth. Advantages: Renewable and can reduce waste. Carbon neutral when managed sustainably. Can be used in existing power plants with little modification. Disadvantages: Can compete with food production if crops are grown specifically for biofuel. Can cause deforestation if not sourced sustainably. Air pollution when burned. 11. Nuclear Power Nuclear energy accounts for over 11% of global electricity generation. Is nuclear power a renewable energy source?  No, nuclear power uses uranium, which is non-renewable. However, it produces low emissions during operation. Advantages of Nuclear Power: Reliable and provides large amounts of energy. Produces low greenhouse gas emissions compared to fossil fuels. Why is nuclear power unpopular with some campaigners? Safety concerns: Accidents like Chernobyl and Fukushima have raised public fears. Radioactive waste: Disposal and long-term storage of nuclear waste remain unresolved. High initial costs: Building nuclear plants is expensive. 12. Worksheet Tasks Task 1: Review the mix of energy sources in the UK’s electricity supply. Task 2: Examine the arguments for and against nuclear energy. 13. Plenary Role of heated water in producing electricity: o Heated water (via combustion of fossil fuels, nuclear, or other methods) produces steam that turns turbines to generate electricity. Mix of energy sources: A combination of renewable and non-renewable sources helps provide a reliable supply of electricity, balancing the intermittent nature of renewables with the reliability of fossil fuels and nuclear power. Fossil fuels as finite resources: They take millions of years to form, and once depleted, cannot be replaced. They are also a major source of greenhouse gases that contribute to climate change. 1. What are Modern Materials? Modern materials are either newly invented materials or materials that have been recently improved or developed. These materials often have unique properties or have been altered in some way to enhance their functionality or aesthetic qualities. Functions: Modern materials can be used to solve design issues, technical constraints, and environmental challenges. Alterations: Materials might be blended, coated, alloyed, or treated to improve their performance. Examples of Modern Materials: Non-stick coatings used in kitchen equipment (e.g., Teflon). Security features on banknotes, like holograms or watermarks, made using modern materials. 2. Biodegradable Polymers Biodegradable polymers are made from vegetable starches, such as corn-starch. Common types include: o Polylactic acid (PLA) – used in 3D printing. o Polyhydroxybutyrate (PHB) – branded as Biopol™. o Polycaprolactone (PCL) – marketed as Polymorph. Challenges: Some biodegradable polymers struggle to decompose in landfill sites due to lack of oxygen and low temperatures that hinder the breakdown process. Example: The Saltwater Brewery in Florida (USA) developed biodegradable, compostable, and edible six-pack rings made from wheat and barley remnants. This process reduces plastic waste. Discussion Point: Consider other common plastic products (e.g., straws, bottles) that could benefit from being made with biodegradable materials. 3. Polymorph and Coolmorph™ Polycaprolactone (PCL) is a low-temperature, hand-mouldable polymer. o Polymorph melts at 62°C. o Coolmorph™ melts at 42°C, making it easier to use. Properties: o Biodegradable and non-toxic. o Can be coloured. o Hand-mouldable: Ideal for modelling and quick repairs. o Reusable: Can be remoulded multiple times. Applications: Household repairs (e.g., fixing plastic objects). Prototyping: Easy to shape and form for design purposes. 4. Flexible MDF Flexible MDF is engineered to bend, allowing designers to create natural curves in their products. Used commonly for: o Shop fittings. o Bespoke commercial projects. How it works: Routed grooves allow the material to bend without breaking, which makes it highly versatile for curved designs. Alternative Material: Flexible plywood is another timber-based material that can be bent and used for similar purposes. 5. Titanium Titanium is a lightweight, tough metal with a low density and excellent corrosion resistance. Applications: o Aerospace: Lightweight and strong, ideal for aircraft components. o Medical: Used in implants and surgical tools because it does not react with the human body. Properties: It is stronger than many other metals, yet lighter, making it ideal for weight- sensitive applications. Other Uses: Sports equipment (e.g., golf clubs, bicycles). Marine: Resistant to corrosion from saltwater. 6. Fibre Optics Fibre optic cables carry light signals through a glass core. Applications: Cable TV and broadband internet infrastructure. Medical uses: Endoscopes help doctors look inside the body without surgery. Military and Police: Can be used in surveillance and communication equipment. Advantages: High-speed data transmission. Lightweight and resistant to electromagnetic interference. 7. Graphene Graphene is a material that is just one atom thick and is 200x tougher than steel. Properties: Stretchable, flexible, and transparent yet impermeable. Highly electrically conductive. Applications: Flexible electronics: Flexible, bendable devices such as smartphones, wearable tech, and foldable screens. Energy storage: Graphene could revolutionize batteries by making them more efficient and faster to charge. Biomedicine: Potential applications in drug delivery and medical devices. Potential Benefits: Flexible electronics could lead to wearable technology that improves the daily lives of consumers. Lighter, stronger materials could assist elderly or disabled individuals with mobility aids or assistance products. 8. Liquid Crystal Display (LCD) LCDs use liquid crystals that align to form images when electricity is applied. Features: Monochrome or full colour versions. Very small and lightweight. Low power consumption. How they work: LCDs do not emit light by themselves; they need a backlight to display images. Applications: Television and computer screens. Smartphones, clocks, and calculators. Advantages:  Thin and compact compared to traditional CRT screens. Energy-efficient. 9. Nanomaterials Nanomaterials are materials with structures between 1 to 1000 nanometres. Benefits: o Increased surface area. o Enhanced chemical reactivity. o Improved strength and flexibility at a smaller scale. What do nanomaterials do? Nanomaterials can: o Enhance performance in various applications (e.g., medical devices, electronics). o Provide lightweight, strong materials that are more durable. 10. Metal Foam Metal foams are created by injecting gas into molten metals such as aluminium or titanium, forming air pockets. Advantages: Lightweight: Metal foams are only about 25% of the mass of solid metals, yet still maintain strength. Recyclable: 100% recyclable, making them environmentally friendly. Applications: Aerospace: Used in aircraft and automotive industries to reduce weight and improve fuel efficiency. Protection: Can be used in crumple zones in vehicles for impact absorption. 11. Worksheet 3 Complete the tasks on modern materials and their applications, including their advantages, disadvantages, and potential uses. 12. Plenary Modern materials shaped by heat: o Flexible MDF and Polymorph are examples of materials that can be shaped using heat. Materials in early development: o Materials like graphene and nanomaterials are still in early stages of research and development but show promise in various fields. Biodegradable polymers reduce fossil fuel usage by being derived from renewable plant-based sources rather than petroleum. This reduces the environmental impact of plastic production. Improving strength-to-weight ratios in automotive materials: o Materials like metal foam and graphene can help improve the performance and fuel efficiency of vehicles by reducing weight without compromising strength. 1. What Are Smart Materials? Smart materials are materials that can respond to external stimuli (such as heat, light, pressure, or moisture) by changing their properties or characteristics. This ability allows these materials to adapt to their environment in a way that traditional materials cannot. External stimuli could be: o Temperature (heat or cold). o Light (UV or visible light). o Pressure (force or stress). o Moisture (water or humidity). Key characteristic:  Reactivity: Smart materials react to changes in the environment, altering their behaviour, shape, or appearance accordingly. 2. Self-Healing Polymers Self-healing polymers are capable of repairing themselves after stress fractures by releasing a resin into the newly formed crack. How it works: Microcapsules of liquid resin are embedded within the polymer. When a fracture occurs, the microcapsules rupture, releasing the resin to fill the crack. The resin then cures and bonds the material back together. Applications: Used in materials like coatings, electronics, or even car parts to increase longevity and reduce maintenance. Triggering the resin: The resin hardens or cures when exposed to specific conditions, such as temperature, light, or the presence of moisture. 3. Self-Healing Concrete Self-healing concrete is designed to repair cracks in structures before they get worse. How it works: Spheres of bacteria are mixed into the concrete. These bacteria contain their own food supply and are dormant in the concrete. When a crack forms and water seeps in, the bacteria activate and feed, producing calcium carbonate that fills the crack, preventing further damage. Benefits:  This type of concrete helps prevent the rusting of steel reinforcements, thus increasing the lifespan of concrete structures and reducing repair costs. 4. Thermochromic Pigments Thermochromic pigments change colour in response to temperature fluctuations. They are sensitive to heat and cold, which causes them to alter their appearance. Applications: Fever scan strips for infants to monitor temperature. Room thermometers that change colour with temperature. Children's cutlery and crockery to show if food or drink is too hot. Colour-changing clothing or novelty goods that change with temperature. Medical/food uses: In the medical industry, these pigments could help monitor body temperature, providing an easier way to spot fever. In food packaging, it could indicate if food or drink has been overheated or is safe to consume. 5. Photochromic Particles Photochromic particles change their properties when exposed to UV light (ultraviolet light). How it works: Silver halide particles within materials react to UV light, causing them to change from clear to dark (as seen in photochromic sunglasses). These particles can take up to two minutes to revert from dark to clear once removed from UV exposure. Applications: Prescription sunglasses that darken in bright sunlight and return to clear indoors. Issues: Over time, these particles can lose their ability to revert to a clear state after exposure to UV light. 6. Photochromic Pigments Photochromic pigments also react to UV light, but their effect only lasts while the UV light is present. Once the light is removed, the pigment will return to its original state. Uses: Common in novelty goods, colour-changing paints, and even security applications (such as on banknotes or documents that change colour when exposed to UV light). Security applications: Could be used to create dynamic security features in products that change their appearance when exposed to UV light, making them harder to replicate or forge. 7. Shape Memory Alloys (SMAs) Shape memory alloys (SMAs), like Nitinol (a nickel-titanium alloy), can "remember" and return to a pre-set shape after being deformed. How it works: Nitinol needs to be heated to around 540°C to be set into a specific shape. When the alloy is deformed and then reheated to about 70°C, it will return to its pre-set shape. Applications: Dentistry: Used in braces that can gradually shift teeth to the desired position. Eyewear: Glasses that can return to their original shape if bent or misshapen.  Heart surgery: In stents that expand when heated inside the body to restore blood flow. 8. Quantum Tunnelling Composite (QTC) QTC is a polymer embedded with metal particles that don't touch each other, creating an unusual material that behaves as both an insulator and a semiconductor. How it works: When pressure is applied, the particles come closer together, turning the material into a conductor, allowing electricity to flow. Applications: Touch-sensitive devices (e.g., keyboards, buttons) that react to pressure. Can be used in flexible electronics, wearable technology, and pressure sensors in various devices. 9. Piezoelectric Material Piezoelectric materials generate an electric charge when subjected to mechanical stress (such as pressure or vibration). How it works: When the material is subjected to stress, the electrical charge produced can be used as a signal or power source. When an electrical signal is applied to piezoelectric material, it deforms and produces vibrations or movement. Applications: Vibration detection: Used in sensors to detect vibrations in machines or structures, helping to monitor for damage. Mobile phones: Used in microphones and speakers to produce sound from electrical signals.  Energy harvesting: Can generate small amounts of energy from everyday movements. 10. Piezo Transducer Piezo transducers convert mechanical energy (movement or vibration) into electrical energy. How it works: When an electrical signal is passed through the piezoelectric material, it causes the material to vibrate, producing sound or triggering an electrical response in a circuit. Applications: Microphones and speakers in mobile phones, toys, and other electronic devices. Vibration sensors for monitoring mechanical systems. 11. Acid or Alkali (pH-sensitive Materials) pH-sensitive materials change colour based on the pH level (acidity or alkalinity) of the substance they come in contact with. How it works: These materials typically use compounds found in lichen, which change colour depending on the pH of the environment. Applications: Litmus paper for testing garden soil, pool water, and skincare products. Can be used in dermatological testing to ensure products are safe for use on the skin. 12. Worksheet 4 Complete the tasks on smart materials, exploring their properties, how they change with different stimuli, and where they are used in real-world applications. 13. Plenary: Designing the Ultimate Car Using Smart Materials Imagine you are a designer for a car manufacturer tasked with creating the best driving experience. Consider how smart materials could improve the car's performance in various ways: o Safety: Shape memory alloys (SMA) could be used in seat belts or airbags to react to an accident and improve protection. o Entertainment: Use of photochromic pigments in windows or lighting to adjust the car's interior lighting based on external UV light or temperature. o Comfort: Use of thermochromic pigments in seats or controls to show temperature levels and adjust for comfort. o Maintenance: Self-healing materials could be used in the exterior to automatically repair small chips or cracks from minor accidents or impacts. o Ease of Use: Piezoelectric materials could be integrated into the dashboard for touch-sensitive controls or as a way to monitor vibrations and alert the driver about potential issues. Key considerations: The use of smart materials in a car could improve safety, comfort, and maintenance, as well as reduce energy consumption through self-regulating systems. 1. What is a Composite Material? Composite materials are materials made by combining two or more different materials to create a new material with enhanced properties. The individual materials used in composites typically have different physical and chemical properties that complement each other, resulting in a superior overall performance.  Key characteristics of composite materials: o Lightweight: Even though the combined materials might be heavy, the resulting composite can be made lightweight. o Stronger: Composites often have improved strength-to-weight ratios. o Durable: Composites can have better resistance to wear and tear compared to individual materials. 2. Concrete as a Composite Material Concrete is a common composite material made by combining: o Cement (binder). o Aggregates (such as sand, gravel, or crushed stone). o Water (to activate the cement). Concrete is very strong when it comes to compression, but it can be weak in tension (it can crack easily under tension forces). Enhancing Concrete: Reinforcing concrete with steel rebar or fibres (e.g., carbon fibre, glass fibre) makes it stronger and more resistant to cracking, improving its overall performance under both compression and tension forces. 3. Types of Reinforced Plastic Glass Reinforced Plastic (GRP) and Carbon Fibre Reinforced Plastic (CRP) are two types of composite materials commonly used in design and manufacturing. Glass Reinforced Plastic (GRP): GRP is a composite material made by reinforcing plastic with glass fibres. Advantages: o Strong, durable, and lightweight. o Resistant to corrosion, making it ideal for marine and outdoor applications. Applications: Boat hulls, storage tanks, car bodies. Carbon Fibre Reinforced Plastic (CRP): CRP is made by reinforcing plastic with carbon fibres. Advantages: o Stronger and lighter than GRP. o Offers higher stiffness, better fatigue resistance, and greater strength-to- weight ratio. Applications: Aircraft, high-performance sports cars, cycling equipment, and some prosthetic devices. Differences: GRP is less expensive but not as strong as CRP. CRP performs better in applications where weight reduction and high strength are crucial. 4. GRP (CRP) Process The process for making a GRP (or CRP) part involves several steps: 1. Prepare the mould (or former). 2. Apply a release agent to prevent sticking. 3. For GRP: a. Apply a gel coat for protection and smooth finish. b. For CRP: Apply the first resin coat. 4. Lay down fibre matting or woven carbon fibre. 5. Work the resin into the fibres to ensure thorough coating. 6. Repeat the layering process (resin and matting) to achieve the desired thickness. 7. Cure: a. GRP parts are left to cure at room temperature. b. CRP workpieces are sealed in a vacuum bag and heated in an oven for curing. 8. Finish: Once cured, the piece is removed from the mould, trimmed, and finished. Precautions:  When working with VOCs (volatile organic compounds) during the curing process, wear appropriate protective gear (such as gloves and masks) and ensure proper ventilation. 5. Technical Textiles Technical textiles are fabrics that have been engineered to have special properties beyond their typical use in clothing. They provide enhanced functionality such as weatherproofing, conductivity, insulation, and increased strength. Functions of technical textiles: Weatherproofing: Protects from rain, wind, or snow. Strengthening: Reinforces the fabric, making it durable and tough. Conductivity and Insulation: Provides electrical and thermal properties (used in e- textiles). 6. Gore-Tex® Gore-Tex® is a membrane used in fabrics that is both waterproof and breathable. How it works: The fabric has 150 million holes per cm². Water droplets are too large to pass through, but water vapour (perspiration) can escape, preventing the wearer from overheating. Applications: Outdoor clothing such as jackets, shoes, and gloves. Sports gear (e.g., hiking, skiing). Military uniforms for protection against harsh weather conditions. 7. Aramids (Aromatic Polyamide) Aramids are tough, heat-resistant synthetic fibers made from polyamide. Characteristics: Cut and tear resistance. Flame resistance (able to withstand extreme temperatures). Thermal insulation. High strength and durability. Examples: Nomex®: Used in fire-resistant clothing (e.g., firefighter suits). Kevlar®: Used in bulletproof vests and high-performance materials (e.g., in cars and airplanes). Flameproof vs. Flame Retardant: Flameproof refers to materials that cannot catch fire. Flame retardant refers to materials that slow down the spread of flames. 8. Conductive Fabrics and Threads E-textiles (electronic textiles) are fabrics that allow electricity to travel through special conductive threads. How it works: Stainless steel or other conductive strands are woven or sewn into fabrics, providing electrical conductivity without sacrificing flexibility. Applications: Touch-sensitive electronics: Clothing that can control devices or adjust temperature settings (e.g., heated jackets). Medical sensors: Used to monitor body temperature or heart rate. Use in Arctic conditions:  Conductive fabrics can be used to make heated clothing or temperature- regulating garments for extreme cold. 9. Microfibres Microfibres are synthetic fibres that are less than one denier thick (much thinner than a human hair). Characteristics: Electrostatic charge: Attracts dust and dirt particles. Softness and lightweight. Common Products: Cleaning cloths: Used for dusting and wiping due to their ability to attract particles. Clothing: Made from polyester and polyamide for breathable, lightweight materials. Pros and Cons: Good: Excellent for cleaning and lightweight clothing. Bad: Non-renewable and not biodegradable. Can contribute to ocean pollution and affect the food chain due to microfibres entering water sources. 10. Microencapsulation Microencapsulation involves enclosing solids, liquids, or gases in tiny capsules. The capsules release their contents under controlled conditions. Active ingredients could include: Thermochromic dyes (that change colour with temperature). Antibacterial materials. Pesticides or perfumes. Applications:  Cosmetics: Perfume or skincare products that release ingredients over time. Food packaging: Containing preservatives that are released under certain conditions. Textiles: Clothing or uniforms with controlled release of scent or antibacterial agents. 11. Plenary Using your knowledge of composite materials and technical textiles, complete Task 3 of your worksheet by applying the concepts to real-world examples and scenarios. 1. What is an Electronic System? An electronic system is a collection of parts or components that work together to perform a specific task or activity. These systems can be found in a wide variety of products, such as: o Security lights: Turn on when motion is detected. o Washing machines: Perform different tasks in a sequence based on a selected program. Key Question for a Security Light Example: Input: The sensor detects movement or changes in light levels (e.g., when it gets dark). Output: The light turns on. How the system works: The system receives input data (sensor detecting movement), processes the data, and makes a decision to activate the light as an output. 2. Subsystems Subsystems are smaller, independent tasks or events that operate within a larger system. For example, in a car:  o Steering system. o Braking system. o Electrical system. o Entertainment system. o Navigation system. o Safety system (airbags, crash sensors). These subsystems often interact with each other but can also function independently within the system. 3. Systems Diagram Systems diagrams (also called block diagrams) are used to represent how systems work. Blocks represent different parts or functions of the system, such as inputs, processes, decisions, and outputs. Arrows indicate the flow of data or energy through the system, showing the direction of movement between blocks. Example: Input: Sensor detects light. Process: A decision is made (e.g., if the light level is below a threshold, turn on the light). Output: Light turns on. 4. Open Loop Systems An open loop system works without feedback. It doesn’t make decisions based on output or results. Example: A toaster that heats the bread for a set time, but cannot adjust for perfect toast (it doesn't "know" if the toast is light or dark enough). It just heats for the same amount of time every time, regardless of the toast's condition. Why can't toasters get it right every time? Because they lack feedback; they don’t measure how toasted the bread is and adjust accordingly. 5. Closed Loop Systems A closed loop system uses feedback to adjust its output based on the input or environment. It monitors the output and adjusts the system's actions accordingly. Example: A car's air conditioning system may adjust the temperature by measuring the current temperature inside the car and adjusting its cooling/heating output accordingly. Decision-making process: The system receives input (e.g., internal car temperature) and compares it to the desired value (set temperature). Based on this feedback, the system decides whether to increase or decrease cooling/heating. 6. Flowcharts Flowcharts are graphical representations of systems or processes, breaking them down step by step. They are commonly used to analyse systems and program microcontrollers in more detail. Common Flowchart Symbols: Oval: Start or end of a process. Rectangle: A process or action. Diamond: A decision point (Yes/No, True/False). Arrow: Direction of flow. Example: A flowchart for a simple system could look like this: Start → Is it dark outside? → Yes → Turn on light → End. → No → Do nothing → End. 7. Circuits and Symbols In electronic systems, circuit diagrams represent how electronic components are connected.  Schematic diagrams are used to show how electrical components are wired together in a simplified form, not like a physical setup but more as a logical representation. Common Symbols: Resistor: A zig-zag line. Battery: Two lines (one long, one short). Switch: A break in a line (often with a gap). LED: A triangle pointing to a line (often with arrows showing light). Transistor: A line with three connections (base, collector, emitter). 8. Input Components Input components trigger a system either manually (e.g., a button) or automatically (e.g., a sensor). Types of Input Components: Switches: Turn a system on or off. Sensors: Detect changes in the environment (e.g., heat, light, movement, sound). o Example: A sound sensor can detect noise and trigger an action (e.g., turn on a security camera). Polarity: Some components, like LEDs, need a specific direction for current to flow. If the polarity is incorrect, the component will not work. Connecting Inputs: Potential divider: A circuit setup that ensures the input signal stays within a defined range. o It consists of a resistor connected to both the positive and negative of the power supply. o This helps prevent input pins from floating, which can cause errors. 9. Analogue Inputs Analogue components provide varying signals (e.g., a temperature sensor that varies its output based on the environment). Example: A street lamp that turns on at dusk uses a variable resistor to adjust sensitivity based on light levels. 10. Output Components Output components convert electrical energy into light, sound, heat, or movement. Examples: LEDs: Emit light. Motors: Cause movement. Speakers: Emit sound. Heating elements: Produce heat. High-Power Outputs: Some output components, like motors or heating elements, require more power than the system can provide. o Transducer drivers (e.g., Darlington pair transistors, field-effect transistors) are used to increase the available power. o Relays are used to control high-power circuits with low-power signals. 11. Transducer Drivers Transducer drivers increase the power supplied to high-power components, such as motors or heating elements. o Relays can switch high-power devices using a low-power signal. Common Household Devices Using High Power: Air conditioners, washing machines, refrigerators, microwaves – all of these require significant amounts of energy to operate. 12. Plenary Open Loop System vs. Closed Loop System: o Open loop systems do not use feedback for adjustments (e.g., a toaster). o Closed loop systems use feedback to monitor and adjust their output (e.g., a car's heating system). How Flowcharts Work: o A flowchart helps map out the steps needed to complete a process, making it easy to visualize the logic and decisions involved in a system. What Transducer Drivers Do: o Transducer drivers allow low-power components to control high-power outputs, ensuring that the right amount of energy is available to power larger devices. Challenge: Create a flowchart that helps you logically navigate to your next lesson by considering decisions about how far you need to travel (e.g., "Is the classroom on the same floor?" → "Yes" → "Turn right" or "No" → "Take the elevator"). 1. Do Products Make Decisions? Yes, electronic products can make decisions based on inputs and programmed logic. For example, an electronic dice knows which number to display based on the input from a random number generator or counter, which is programmed into the system. Example: Electronic Dice Input: The button is pressed or motion is detected.  Process: The microcontroller counts or generates a random number. Output: The corresponding number is displayed on the dice. 2. What is a Process? Process refers to a series of actions or steps taken to achieve a particular result. In electronics, processes often include: o Timing: Delays or specific time intervals. o Counting: Incrementing or decrementing numbers. o Amplifying: Increasing signal strength. o Comparing: Making decisions based on inputs (e.g., checking if a value exceeds a threshold). Other Electronic Processes: Conversion: Analog-to-digital (ADC) or digital-to-analog (DAC) conversion. Signal filtering: Removing unwanted signals or noise. Logic operations: AND, OR, NOT. 3. Digital vs. Analog Signals Analog signals have an infinite range of values between their minimum and maximum points. o Example: A temperature sensor producing a smooth, continuous output. Digital signals are either on or off (binary states), typically represented by 0 (off) and 1 (on). o Example: A switch, where it is either on or off. Which type of signal does a switch produce? Switches produce digital signals, as they are either on or off. 4. Integrated Circuit (IC) Integrated Circuits (ICs), also known as microchips, are small packages of electronic circuits that perform specific tasks. o Programmable ICs are called microcontrollers and can be adapted for various tasks. o Most ICs come in a Dual In-Line Package (DIL) for easy mounting on a circuit board. Benefits of Microcontrollers: Microcontrollers (e.g., PICs) are programmable and adaptable, meaning they can perform many functions, reducing the need for multiple discrete components. Smaller circuit boards can be designed, leading to less complexity and lower costs. Drawback of Using PIC for Simple Tasks: For very simple, one-time tasks, using a PIC may be overkill and may not be cost- effective. 5. Programming a PIC A PIC (Peripheral Interface Controller)'s functions are controlled by a program that is loaded through a download cable. The program can be created using specialized software: o Graphical flowcharts for easier visualization. o Code languages like BASIC for more precise control. PICs can be reprogrammed multiple times, allowing for updates and corrections. 6. Digital or Analog Inputs? When programming PICs, it’s important to choose the correct type of input: o Switches provide digital signals (either on or off). o Thermistors, LDRs (Light Dependent Resistors), and microphones provide analog signals, with a continuous range of values. 7. Using Analog Sensors Analog sensors provide continuous data (e.g., temperature or light levels). Since PICs can't process infinite ranges of values, the signal is quantized into smaller sections. o Analog signals are divided into 256 equal sections (values range from 0 to 255). o When the analog signal reaches a certain threshold, the PIC processes it accordingly. 8. Output Components Buzzers and speakers are output components that produce sound: o Buzzers typically emit a single frequency and are ideal for system alerts or alarms. o Speakers have a broader frequency range and are used for more complex audio output, such as speech and music. Example of Buzzer Use: A buzzer would be more appropriate in an alarm system, where a simple alert sound is needed rather than complex audio. 9. Timers in Electronics Timing is an essential process in electronics for controlling events or delays. Microcontrollers typically have an internal clock that enables accurate timing. Types of Timers: Monostable (Single pulse, one-time event): o Example: Automatic door opener. o The system remains on for a set time and then turns off. Astable (Continuous pulses, oscillating):  o Example: Flashing lights (on tall buildings or aircraft). o The system continuously alternates between on and off states. o The frequency (measured in hertz) controls the speed of the pulse cycles. Example of a Flashing Road Beacon: It uses an astable timer to produce a continuous flashing signal. 10. Counting in PICs PICs can be programmed to count up or down in response to pulses, eliminating the need for traditional counters. Popular counters include: o Decade counter (4017): This counter has 10 outputs, incrementing one step for each pulse. o 7-segment display decoder (4026): Converts counter pulses into numbers and outputs them to a 7-segment display. What Does “Cascade” Mean? Cascading means linking multiple ICs together so that the output of one IC becomes the input of the next IC, allowing for larger counting ranges or more complex systems. 11. Worksheet 7 Task 1: Identify input components (e.g., switches, sensors) and their associated digital or analog signals. Task 2: Explore the use of timers (monostable and astable) and counters (decade counter, 7-segment decoder) in different systems. 12. Plenary Downloading a Track:  o When you download a track from a music site, the file is transferred from the server to your device, typically as a digital file (e.g., MP3). What Happens When You Play a Track?: o The digital file is converted into an analog signal by the device’s DAC (Digital-to-Analog Converter). o The signal is then sent to the speakers or headphones, which convert the electrical signals back into sound. 1. What is a Mechanical Device? Mechanical Device: A tool or machine that uses mechanical energy to perform a task. Examples: o Hammer: Yes, a hammer is a mechanical device because it uses force to perform a task (e.g., driving a nail). o Scissors: Yes, scissors are mechanical devices because they use levers to create cutting force. 2. Types of Motion Motion is the act of an object changing position. There are various types of motion that can be combined or transformed into one another. Linear Motion Definition: Movement in one direction along a straight line. Example: A car moving along a road. Reciprocating Motion Definition: A repetitive back-and-forth or up-and-down movement along a straight path. Example: The back-and-forth motion of a saw blade. Oscillating Motion Definition: A repetitive back-and-forth motion along a curved path. Example: A pendulum on a grandfather clock or a children's playground swing. Rotary Motion Definition: Movement in a circular motion around a fixed axis. Example: The wheels of a car or the spindle of a power tool. 3. Levers and Mechanical Advantage (MA) Levers are simple machines that help us gain a mechanical advantage by using a pivot or fulcrum. The mechanical advantage (MA) helps to change the magnitude of the force needed. MA Formula: MA=Effort ArmLoad Arm\text{MA} = \frac{\text{Effort Arm}}{\text{Load Arm}}MA=Load ArmEffort Arm Elements of a Lever: o Effort: The force applied. o Load: The force to be moved. o Fulcrum: The pivot point. Types of Levers First-Order Lever (Class 1): o Example: A seesaw or scissors. o The fulcrum is in the middle, with the effort and load at opposite ends. o If the fulcrum is moved to the left: The effort required to lift the load will increase. Second-Order Lever (Class 2): o Example: Wheelbarrow or nutcracker. o The load is between the effort and the fulcrum. Third-Order Lever (Class 3): o Example: Tweezers or fishing rod. o The effort is between the load and the fulcrum. 4. Equilibrium Equilibrium occurs when the effort and load are balanced. Seesaw Example: If two people of the same weight sit at equal distances from the fulcrum, the seesaw will balance. If one person moves further from the fulcrum, their side will lower (greater distance = greater force). Balancing the Seesaw: If you have twice the mass of the other person, you would need to sit half the distance from the fulcrum to balance the seesaw. 5. Linkages Linkages are systems of rigid parts that work together to transfer or change motion and force. Types of Linkages: Reverse Motion Linkage: o Function: Changes the direction of motion (e.g., input pulled, output pushed). o Example: Some door-opening mechanisms. Parallel Motion Linkage: o Function: Keeps the output direction the same as the input. o Example: The push-pull linkage in mechanical arms. Bell Crank Linkage: o Function: Converts horizontal motion into vertical motion (or vice versa). o Example: Steering mechanisms in vehicles. Crank and Slider: o Function: Converts rotary motion into reciprocating motion and vice versa. o Example: Found in engines where pistons move up and down. Treadle Linkage: o Function: Converts rotary motion into oscillating motion and vice versa. o Example: Sewing machines or windscreen wipers. 6. Rotary Systems Rotary Systems are mechanisms where rotary motion drives other components. Cams: Shaped pieces attached to a camshaft that change rotary motion into reciprocating motion via a follower. Types of Cams: Eccentric Cam: Circular but offset, creating varying motion. Pear Cam: Has a rounded shape that results in smooth changes in motion. Snail Cam: Creates slow, smooth movement followed by quick drops. Heart-Shaped Cam: Used for precise timing mechanisms. Types of Followers: Flat Follower: A flat surface that follows the cam's rise and fall. Knife-Edged Follower: A pointed surface used for precision in high-speed cams. Roller Follower: A rolling follower that reduces friction. 7. Gear Trains Gear Trains are used to transfer motion and torque between machine components. Key Concepts: Drive Gear: The gear that provides the power. Driven Gear: The gear that receives the power. Gear Ratio: The ratio of teeth between gears determines the speed and torque transfer. o Example: If a drive gear with 20 teeth rotates a driven gear with 10 teeth, the driven gear will rotate twice for each turn of the drive gear. This is called gearing up. Idler Gear: A gear placed between the drive and driven gears to ensure the same direction of rotation. o Does the size of the idler gear affect the gear ratio? No, the idler gear does not affect the gear ratio; it only changes the direction of rotation. 8. Pulleys and Belts Pulleys and belts transfer rotational power from one place to another. Pulleys are often grooved to help grip the belt, which is usually made of rubber or other materials to increase friction. Example Uses: Conveyor belts, engine components, and fans. Block and Tackle Block and Tackle Systems use pulleys to lift heavy loads by reducing the effort needed. o More pulleys mean less effort is needed to lift the same weight, but more rope must be pulled. o Example: Lifting heavy loads using a pulley system. Calculations: If a 100kg load is lifted using 4 pulleys, the effort will be reduced by a factor of 4. The load will feel 25kg. If 3 pulleys are used, you will need to pull 3 meters of rope to lift a load by 1 meter. 9. Worksheet 8 Task 2: Work through problems related to gear ratios, pulleys, and mechanical advantage. 10. Plenary Four Forms of Motion: o Linear Motion (e.g., car driving straight). o Reciprocating Motion (e.g., saw blade moving back and forth). o Oscillating Motion (e.g., playground swing). o Rotary Motion (e.g., rotating wheel). Examples of Levers: o Class 1: Seesaw. o Class 2: Wheelbarrow.  o Class 3: Tweezers. Three Linkages: o Reverse motion linkage: Changes direction. o Parallel motion linkage: Keeps direction the same. o Crank and slider: Converts rotary to reciprocating motion. Mechanical Advantage (MA): The ratio of the output force to the input force in a machine, which shows how much a machine amplifies the force. Drive Gear vs. Driven Gear: The drive gear powers the system, while the driven gear receives the power.