Short Questions Study Material and Sample Answers

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Short Questions Study Material and Sample Answers Sign: Meaning: Flammable Material or Liquid This

Meeting Point This is used in the case of evacuation in which this sign is fixed in a safe place so

Face Mask Mandatory This means that a face mask must be worn in a designated area or when

Note that id any sign has a blue back ground it means mandatory Safety Glasses/Goggles Mandatory

Mandatory This means that a ear muffs or plugs must be worn in a designated area or when Face

Blade Rotating - This means that there is a blade rotating at high speed and that you should be

person could make electrical contact with equipment or a conductor and may sustain an injury from

1 Short Questions Study Material and Sample Answers Sign: Meaning: Flammable Material or Liquid This means that a material or liquid will catch fire and support combustion easily. Meeting Point This is used in the case of evacuation in which this sign is fixed in a safe place so people can gather here. Face Mask Mandatory This means that a face mask must be worn in a designated area or when conducting a certain process. Note that id any sign has a blue back ground it means mandatory Safety Glasses/Goggles Mandatory This means that a safety glasses/goggles must be worn in a designated area or when conducting a certain process. Ear Protection Mandatory This means that a ear muffs or plugs must be worn in a designated area or when conducting a certain process. Face Shield Mandatory This means that a face shield must be worn in a designated area or when conducting a certain process. Danger Blade Rotating - This means that there is a blade rotating at high speed and that you should be cautious and keep your hands at a safe distance Electrical Hazard- a dangerous condition where a person could make electrical contact with equipment or a conductor and may sustain an injury from shock Irritant This means that chemicals will irate your skin and may cause redness or blisters on your skin Toxic - Can cause death, if swallowed, breathed in or absorbed by skin C.Campbell 1 St. Mary s D.S

Technology in Society Common Short Questions Abbreviation: ROM RAM USB CPU VDU WWW WEEE CAM CAD Meaning: Read Only Memory Random Access Memory Universal Serial Bus Central Processing Unit Visual

using manufacturing methods to transform raw ingredients into neatly packaged goods, which have a longer shelf life. Processed foods often contain preservatives, colourings and sweeteners.

2 Technology in Society Common Short Questions Abbreviation: ROM RAM USB CPU VDU WWW WEEE CAM CAD Meaning: Read Only Memory Random Access Memory Universal Serial Bus Central Processing Unit Visual Display Unit World Wide Wed Waste Electric Electronic Equipment Computer Automated Manufacture Computer Automated Design Processed Food vs Fresh Food Processed Food - processed foods are produced using manufacturing methods to transform raw ingredients into neatly packaged goods, which have a longer shelf life. Processed foods often contain preservatives, colourings and sweeteners. Fresh Food - Relates to food in it raw form. An example of this is fruit and vegetables that are grown on farms. These foods generally have a shorter shelf life and take longer to prepare. Processed Food Advantages: Longer shelf life Easy to cook or prepare and sometimes ready to eat Can be very taste and enjoyable to eat Very convenient Disadvantage: Low nutritional Value More Expensive Contain artificial ingredients like colourings, preservatives and sweeteners that are bad for our health. They often contain excessive amounts of sugar and salt Bulky packaging can lead you to believe that you are getting more that you actually are C.Campbell 2 St. Mary s D.S

Fresh Natural Food Advantages: Very good for you High nutritional value High in vitamins

taste than processed food Technology in Society Symbols Symbol: Meaning: Recycle this

placed on packaging material and it symbolises that the material should be disposed of

the normal manner and therefore must be disposed in a correct manner generally by a

3 Fresh Natural Food Advantages: Very good for you High nutritional value High in vitamins and mineral Disadvantages: Short shelf life Time consuming and difficult to prepare Less taste than processed food Technology in Society Symbols Symbol: Meaning: Recycle this symbol is placed on any material that is recyclable Disposable this symbol is generally placed on packaging material and it symbolises that the material should be disposed of after use Non Disposable - this symbol shows that a product should not be disposed of in the normal manner and therefore must be disposed in a correct manner generally by a disposal contractor or recycling centre. Example Batteries/ Mobile phones. C.Campbell 3 St. Mary s D.S

Clothing and Fabrics Natural vs. Synthetic Fabrics/Material Natural fabrics are made from things that grow -- wool, cotton, flax, hemp, linen, etc.

Synthetic fabrics are made from petroleum products-- polyester, nylon. They are used to make clothing generally of low quality.

Natural: Wool Leather Rubber Cotton Linen Silk Synthetic: Polyester Nylon Spandex Lycra Electronics Revision: Component: Appearance: Symbol: Function: Capacitor Used to Store energy and smoothen out

4 Clothing and Fabrics Natural vs. Synthetic Fabrics/Material Natural fabrics are made from things that grow -- wool, cotton, flax, hemp, linen, etc. These are generally used for fine, high quality or traditional clothing. This would be things like dressy suits and jackets. These materials are more expensive than synthetic fabrics. Synthetic fabrics are made from petroleum products-- polyester, nylon. They are used to make clothing generally of low quality. However they are commonly used for sporting cloths such as jerseys as they are lighter, they retain less sweat and are easier to clean than natural fabric. Natural: Wool Leather Rubber Cotton Linen Silk Synthetic: Polyester Nylon Spandex Lycra Electronics Revision: Component: Appearance: Symbol: Function: Capacitor Used to Store energy and smoothen out current Thermistor Thermistor = Temperature Dependant Resistor The resistance will change with the temperature. Variable resistor Used to change the resistance by twisting the spindle at the top Reed Switch Consists of two thin plates in a glass case and when a magnet cones close to the two plates they will connect completing a circuit Transistor Amplifies current and acts as an electronic switch C.Campbell 4 St. Mary s D.S

LDR -Light Dependant Resistor Diode The resistance of

High light levels = Low resistance and low light levels

the other LED Light Emitting Diode Allows current to

through it lights up PTM Push to Make When the switch is

the switch is pressed it break the circuit Buzzer When

Light Bulb When current flows through a bulb it lights

a circuit Ammeter Measures the current in a circuit and

the voltage/ potential difference in a circuit and must

5 LDR -Light Dependant Resistor Diode The resistance of the LDR changes with the light level. High light levels = Low resistance and low light levels =high resistance Allows current to flow one way and not the other LED Light Emitting Diode Allows current to flow one way and not the other and when current flows through it lights up PTM Push to Make When the switch is pressed it completes the circuit PTB Push to Break When the switch is pressed it break the circuit Buzzer When current flows through a buzzer it omits a bussing sound Light Bulb When current flows through a bulb it lights up Relay Electronic switch used to power a second circuit. Works with a magnetic coil that pulls a pin to complete a circuit Ammeter Measures the current in a circuit and must always be connected in series Voltmeter Measures the voltage/ potential difference in a circuit and must always be connected in parallel Ohmmeter Measures the resistance in a circuit and must always be connected in series C.Campbell 5 St. Mary s D.S

Darlington Pair DPDT Double pole Double throw Two transistor connected one after the other to give increased amplification and make sensor

Also it can be used to power two different circuits with the flick of a switch.

It can be used to measure voltage, current, resistance, and also test diodes and continuity in a circuit.

Wires and components are simply pushed into the holes to form a completed circuit and power can be applied.

moved easily to a new position on the board.

6 Darlington Pair DPDT Double pole Double throw Two transistor connected one after the other to give increased amplification and make sensor circuits more responsive Commonly used to turn a motor clockwise and then with the flick of a switch turn it anti clockwise. Also it can be used to power two different circuits with the flick of a switch. Multimetre: A multimeter is an electronic measuring instrument that combines several measurement functions in one unit. It can be used to measure voltage, current, resistance, and also test diodes and continuity in a circuit. Circuit Construction: Breadboards: Breadboards are used to test circuits. Wires and components are simply pushed into the holes to form a completed circuit and power can be applied. One of the main advantages of using a breadboard is that the components are not soldered and if they are positioned incorrectly they can be moved easily to a new position on the board. Stripboard (veroboard): The red lines on diagram 2 show how some vertical columns and horizontal rows are internally connected. When power is applied to the breadboard current flows along these internal connections. Consists of a grid of holes with copper tracks running along it. When power is applied to the board current will flow along the copper tracks. Electronic components are places into the holes and then soldered to the copper track. C.Campbell 6 St. Mary s D.S

Printed Circuit Boards: A printed circuit board are generally unique and are created

The boards are made with glass reinforced plastic and consist of drilled holes for

On the underside of the board there are copper tracks which allow current to flow

As they are created specifically for the circuit they are very neat and tide in

In addition to this they are easy to construct and trouble shoot.

7 Printed Circuit Boards: A printed circuit board are generally unique and are created for a specific circuit. The boards are made with glass reinforced plastic and consist of drilled holes for the electronic components. On the underside of the board there are copper tracks which allow current to flow between the components. As they are created specifically for the circuit they are very neat and tide in comparison to other method. In addition to this they are easy to construct and trouble shoot. Mechanics: Mechanism: Diagram: Function/ Description: Spur Gear Rotating toothed cog used to transmit motion or torque. Generally used in a gear train to speed up or slow down motion. Gear Train Consists of spur gears in mesh. Used to slow down or speed up motion. A gear train can also be used to change the direction of motion. C.Campbell 7 St. Mary s D.S

Compound Gear Compound gear is a number of gears fixed together.

Worm and Wheel Fixed Pulley Movable Pulley The worm consists of screw tread which is in mesh with a wheel.

This is a failsafe mechanism as the wheel cannot rotate the worm (so it can hold a load) A pulley is a wheel on an

A fixed pulley has no mechanical advantages and is often used in hard to reach places like flag poles.

This pulley system has mechanical ad vantages of 2 meaning that if you want to lift a load of 200n you will only

Ratchet and Pawl Cam and Follower Consist of a toothed gear with a spring loaded finger.

This allows it to hold a heavy load without slipping and also prevents it from turning backwards The cam and follow

8 Compound Gear Compound gear is a number of gears fixed together. The two or more gears are generally different sizes but they will rotate at the same speed. Used to slow down, speed up motion. Bevel Gear Bevel gears are used to change the direction or the drive by 90 degrees. Worm and Wheel Fixed Pulley Movable Pulley The worm consists of screw tread which is in mesh with a wheel. As the wheel rotates it turn the wheel at a greatly reduced speed. This is a failsafe mechanism as the wheel cannot rotate the worm (so it can hold a load) A pulley is a wheel on an axle that is designed to support movement of a cable or belt along its circumference. A fixed pulley has no mechanical advantages and is often used in hard to reach places like flag poles. Consists of a pulley that moves with the load. This pulley system has mechanical ad vantages of 2 meaning that if you want to lift a load of 200n you will only have to apply a force of 100n however the rope/belt will move twice as far as the load. Ratchet and Pawl Cam and Follower Consist of a toothed gear with a spring loaded finger. As it rotates the finger will slot into the gear. This allows it to hold a heavy load without slipping and also prevents it from turning backwards The cam and follow transfers rotary motion into linear motion. The cam consists of a shaped disk and as it rotates the follower (Knife point, roller etc..) will move up and down depending on the shape of the cam. Chain and Sprocket Lever Used to transfer motion between two axial. Commonly used in bicycles. The chain is much stronger than a belt and also less likely to slip. However it needs to be lubricated to ensure it moves freely and doesn t rust. A ridge body that rotates around a fixed point known as the fulcrum. Used to lift large load with a large mechanical advantage. C.Campbell 8 St. Mary s D.S

Linkage Consists of a series of levers connected together.

Common ones are the bell crank linkage, reverse motion, and parallel motion linkage.

Tenon Saw Piercing Saw Used to cut wood.

joinery. Can only cut to a limited dept.

9 Linkage Consists of a series of levers connected together. They are used to produce all types of movement. Common ones are the bell crank linkage, reverse motion, and parallel motion linkage. Materials Processing and Tools Name: Diagram: Function: Hacksaw Used to cut metals and plastics Tenon Saw Piercing Saw Used to cut wood. Has a brass strip which ensures the Blade is steady thus making it accurate and good for fine joinery. Can only cut to a limited dept. Used for cutting curves profiles in metals and plastics Coping Saw Used for cutting curves profiles in wooden materials. Countersink Bit Used to cut a conical (cone) shaped hole to allow a countersunk screw sit flush with the top of the surface Spade Bit Used for drilling large radius holes with an electrical or pillar drill. Leaves a rough finish and breakout can be an issue Marking Gauge Used for marking line along the grain and also the end grain on wooden material/ C.Campbell 9 St. Mary s D.S

Tinsmiths Snips Hot wire cutter Pop Riveter Mallet Used for cutting out soft sheet material such as copper or

Used for cutting out modelling foam into various shapes. Consists of a hot wire that burns through the foam.

Handles are pulled together which closes the rivet thus holding the two pieces together.

Tri square Used for checking if a materials is square (90degrees) and also for squaring lines around wooden material.

waste materials and smoothening metals and plastics.

10 Tinsmiths Snips Hot wire cutter Pop Riveter Mallet Used for cutting out soft sheet material such as copper or aluminium. U should cut close to the line as thin material is difficult to file with out bending. Used for cutting out modelling foam into various shapes. Consists of a hot wire that burns through the foam. Used to permanently fix materials together. Handles are pulled together which closes the rivet thus holding the two pieces together. Used for driving chisels and also for assembling wooden artefacts in a manner that doesn t damage the material. Tri square Used for checking if a materials is square (90degrees) and also for squaring lines around wooden material. Scriber Used for drawing lines on metals Dividers Used for drawing circles and arcs on metals File Used for removing waste materials and smoothening metals and plastics. Chisel Used for peering waste material and also for chopping pout mortise joints Snips Used for cutting wire and also for moving the insulation from wire Hammer Many different types claw hammer and the ball pein are most common. They are general purpose hammer used for driving nails and bending meats. C.Campbell 10 St. Mary s D.S

11 Materials Plastics: Thermosetting Plastics these are plastics that can be heated and formed only once. They are generally hard and strong. If headed a second time they will bend rather than melt or soften. Examples include: Thermoplastics: these are plastics that can be heated and formed over and over again. These are widely used in technology for this reason. Examples are acrylic and Perspex. Metals: Ferrous Metals are metals that contain iron. These metals are magnetic and will rust. Examples are steel and cats iron. Examples steel and pig iron. Non Ferrous Metals are metals that do not contain iron. They are not magnetic and they will not rust. Examples include copper and aluminium. Alloys are a mixture of two or more metals. The combination of the metals will create a metal with superior properties to each of the individual metals. Examples include Brass (copper and zinc) Bronze (copper and tin) Wood/ Timber Hardwoods are generally come from deciduous trees (lose their leaves in winter). Hard wood are hander, stronger and more difficult to work with then softwoods. They are generally more attractive and expensive. Deciduous trees take up to 100 years to mature making them scarcer than soft woods. Native Hardwood: - Oak, Ash and Beech. Non Native:- Mahogany and Teak. Softwoods generally come for coniferous trees (keep their leaves in winter). They are softer and easier to work with than hard woods. They are a very light colour in appearance. They mature between 20 and 30 year depending on climate making them significantly cheaper than hardwoods. Native Sitka Spruce and Scots Pine Non Native Cedar and Douglas Fir Manufactured Board these are man made from the processing of timber and timber products. They can be made from things like saw dust or recycled wood or wood products thus helping forest conservation. One major advantage is that they come in sheet format meaning they can be significantly wider than a hardwood/softwood plank. In addition they can have improved water/moisture resistance properties due to the adhesives used in their manufacture. Examples : Plywood (veneers glue together), MDF Medium density fibre board (compacted wood partials glued together) Chipboard (compacted wood chippings glued together) C.Campbell 11 St. Mary s D.S

Design and Technology Resistant materials Key words and definitions

Design and Technology Resistant materials Key words and definitions Word Acrylic Definition a type of thermoplastic, which is hard and can be transparent. Used to make shop signs. Perspex is a trade/brand