2/3 Core Technical Principles ✅

What are modern materials

Materials that have been engineered to have improved properties

Graphene

• A single layer carbon material

• Hypothetically 100x stronger than steel but we cannot manufacture it in large enough quantities to prove this

• strong and light

titanium

• A modern metal used in sporting and medical applications

• Has a very high strength to weight ratio

Metal foams → properties, produced by, advnatages

• properties - strong, lightweight, absorbs shock

• produced by - injecting gas or foaming agent into molten metal

• advantages - Retains lots of strength without the density of a solid metal

LCDs

• Use light-modulating properties of liquid crystals to display an image

• When charge is applied the shape changes to either block light or let it through, allowing text or images to be displayed

Nanomaterials - uses, properties

• Tiny particles used in thin films or coatings - e.g. On smartphones

• Repel water

What are smart mateirals

Materials that show physical change in response to an external stimuli

Examples of smart materials

Shape memory alloys, thermochromic pigments, photochromic pigments

Thermochromic pigments

• Change colour when stimulated by heat

• Used in childrens thermometers

Shape memory alloys

• Change shape when stimulated by heat or electricity

• Can be heated and deformed and return to original shape when reheated

• Used in dental braces

Photochromic pigments

• Change colour when stimulated to light

• Usually UV light

• Used in clothing

what are composite materials

Materials made of different materials materials which are combined to improve their properties

examples of composite materials

GRP, CRP, GRC

GRP - materials and uses

• Glass reinforced plastic

• Made of glass fibres and resin

• Used for boats

CRP

• Carbon reinforced plastic

• Made of carbon fibre and resin

• Used for F1 cars, crash helmets

GRC

• Glass reinforced concrete

• Made of glass fibre and concrete

• Used for street furniture

what are technical textiles + some examples

• textiles that have had their fibres spun in a way that makes them enhanced

• examples - conductive farbics, fire resistant fabrics, kevlar, micro encapsulation

conductive fabrics

• allow a small electrical current to pass safely through them

• used in touch screen gloves

fire resistant fabrics

• more resistant to fire than other textiles, thanks to chemical treatment or manufactured fireproof fibres

• used in furniture where fire safety is paramount

kevlar

• tightly woven fabric with good impact resistance

• used in bulletproof vests

micro encapsulation

• Micro encapsulation involves encapusalting liquid or solid substances in tiny thin walled bubbles

• These microspheres gradually release active agents when rubbed

• They are used in scratch and sniff perfume or afterhsave samples in magazines

Light sensors → component name, what they do, resistance

• Component name - light dependent resistor (LDR)

• A light sensor is sensitive to a change in light

• Its resistance increases in the dark so it can act as a switch, turning on streelights in the dark

Temperature sensors → component name, how they work, resistance

• Component name: Thermistor

• Sensitive to change in temperature

• It resistance increases as temp changes, so it can act as a switch to turn off the oven when it's reached a desired temperature

What are switches

Mechanical switches are added to systems, allowing them to be turned on and off

Pressure switches

• Component name: pressure switch

• Sensitive to pressure or weight applied

• Used in cars to remind you to put your seatbelt on

Other types of switches

• Toggle switches - complete the circuit and remain on until turned off e.g. Light switches

• PTM (push to make) switches - when you push the switch the circuit is completed and turned on e.g. Door bell

• PTB (push to break) switches - when you push the switch the circuit is broken and turned off e.g. Keep doors open button in an elavator

examples of outputs

Buzzers, speakers, lamps

buzzer, speaker, lamp

buzzer

• Component name - buzzer

• When a current passes through the buzzer it moves and makes sound

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Speaker

• Component name - speaker

• When a current passes through the spaker it creates vibrations and produces sound

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Lamp

• Component name - lamp

• Produces light and heat when elec passes through the filament

What are the types of movement

• Linear - straight line

• Rotary - moves around an axis

• Reciprocating - moves up and down or back and forth

• Oscillating - curved backwards and forwards movement