Name:_________________ C.Campbell 1 St. Mary’s D.S 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
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Short Questions Study Material and Sample Answers_____ C.Campbell 1 St. Mary’s D.S Short Questions Study Material and Sample Answers Sign: Meaning: Flammable Material or Liquid –This
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Name:_________________
C.Campbell 1 St. Mary’s D.S
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
Name:_________________
C.Campbell 2 St. Mary’s D.S
Technology in Society Common Short Questions
Abbreviation: Meaning:
ROM Read Only Memory
RAM Random Access Memory
USB Universal Serial Bus
CPU Central Processing Unit
VDU Visual Display Unit
WWW World Wide Wed
WEEE Waste Electric Electronic Equipment
CAM Computer Automated Manufacture
CAD 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: Disadvantage:
Longer shelf life
Easy to cook or prepare and sometimes ready to eat
Can be very taste and enjoyable to eat
Very convenient
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
Name:_________________
C.Campbell 3 St. Mary’s D.S
Fresh Natural Food
Advantages: Disadvantages:
Very good for you
High nutritional value
High in vitamins and mineral
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.
Name:_________________
C.Campbell 4 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. 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: Synthetic:
Wool Leather Rubber Cotton Linen Silk
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
Name:_________________
C.Campbell 5 St. Mary’s D.S
LDR -Light Dependant Resistor
The resistance of the LDR changes with the light level. High light levels = Low resistance and low light levels =high resistance
Diode
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
Name:_________________
C.Campbell 6 St. Mary’s D.S
Darlington Pair
Two transistor connected one after the other to give increased amplification and make sensor circuits more responsive
DPDT – Double pole Double throw
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):
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.
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.
Name:_________________
C.Campbell 7 St. Mary’s D.S
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.
Name:_________________
C.Campbell 8 St. Mary’s D.S
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
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)
Fixed Pulley
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.
Movable Pulley
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
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
Cam and Follower
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
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.
Lever
A ridge body that rotates around a fixed point known as the fulcrum. Used to lift large load with a large mechanical advantage.
Name:_________________
C.Campbell 9 St. Mary’s D.S
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
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.
Piercing Saw
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/
Name:_________________
C.Campbell 10 St. Mary’s D.S
Tinsmiths Snips
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.
Hot wire cutter
Used for cutting out modelling foam into various shapes. Consists of a hot wire that burns through the foam.
Pop Riveter
Used to permanently fix materials together. Handles are pulled together which closes the rivet thus holding the two pieces together.
Mallet
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.
Name:_________________
C.Campbell 11 St. Mary’s D.S
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)