chapter technological systems · chapter 7 what is a system? technological systems in technology,...

CHAPTER

7W H AT I S A SYS T E M ?

Technological systems

In technology, technical objects are often broken down into smaller parts so that they can be better designed, made or analyzed. This makes it easier to understand how different parts interact. This technique treats individual objects as technological systems.

For example, a train is a technological system. It is designed to carry passengers from one point to another. However, the train itself is made up of smaller systems: the control cab, the cars, the brakes, etc. Each component has a specific function and can be further split into smaller systems.

In technology, a system is a group of parts, mechanisms, devices or machines that are assembled to perform a specific task.

In this chapter, you will learn about the characteristics of a technological system and discover the role of each component that makes up a system.Then, you will examine a manufacturing process sheet and learn how it is used.Finally, you will look at how energy is transformed within a technological system.

The technological 196 world

13848_worlds2_ch7_192-223_ep4.indd 196 2017-01-10 1:11 PM

The elements that describe a system are said to be characteristics of a system. They are summed up in the diagram below.

D E F I N I T I O N

Technological systems are all around you. Your pencil sharpener, your music player and your bike are all examples. What do these systems have in common?

What are the characteristics of a system? All technological systems, no matter how big or small, simple or complex, share certain characteristics.

7.1

7.1.1

Characteristics of a system

General diagram of a system

Inputs (elements that go

into a system to help it function)

Outputs (elements

that exit a system once the processes

are complete)

Overall function (describes what the system needs to do)

Processes (series of actions

that the system must perform to inputs to fulfill its role)

Controls (manage or change what happens

in the system)

Chapter 7 197 Technological systems


A simple system and its characteristics Look at this assembly. The diagram below describes the characteristics of this simple system.

The five characteristics outlined above apply to all technological systems.

Simple lighting system

Overall function. This assembly can be considered a system. It is made up of several pieces that have been put together to perform a certain task, in this case providing light.

Control. A switch is used to start or stop the flow of electricity to the light bulb.

Input. The light bulb needs to be connected to an electric circuit to work.

1

2

Process. As the electricity flows through the light bulb, it heats the tungsten wire inside the bulb.

43 Output. The heated tungsten wire becomes incandescent (it emits light).

5

Switch

Providing light

Switch

Incandescence (tungsten wire heated

until it is white-hot)Electricity Light

Electric wires

Light bulb

Battery



Details about the characteristics of a system Let’s take a closer look at the characteristics of a technological system.

The overall function describes what a system needs to do. The overall function of an airplane engine is to propel the airplane into the atmosphere. The overall function of a heating system is to heat. The overall function of a telephone is to allow two or more people to have a conversation at a distance.

Controls manage or change what happens in a system. There are many different types of controls. They can be:• mechanical, like the gear shifters on a bicycle,

which change the bicycle’s speed;• electric or electronic, like the keys on a keyboard or

buttons on a remote control;• optical, like the automatic openers on some doors.

Inputs are any elements that enter a system and help it function. Inputs generally fall into one of seven categories:• people: workers, suppliers, etc.;• equipment: saws, trolleys, trucks, etc.; • information: knowledge, instructions, etc.;• energy: muscle power, electricity, fuel, etc.;• materials: wooden boards, fabric, nails, etc.;• capital: money, buildings, land, etc.;• time: production time, management time, etc.

An airplane engine

A control panel

A production line

Controls

Inputs

Overall function of the system



Details about the characteristics of a system (continued)

Processes are the series of actions that a system must do to its inputs to fulfill its role. Take a dryer, for example. To dry clothes, the dryer needs to heat a certain amount of air. It then pushes the hot air into the drum, which spins to bring clothes into contact with the hot air. The damp air is then removed and replaced with more hot dry air.

An output is anything that exits a system after it has finished working. Some outputs are desirable. We call these “results.” For example, when you start a car and press the gas pedal, motion is a desired output. However, systems rarely have just one output.Some outputs are not desirable. They are called “waste.” A car, for example, produces exhaust fumes and dirty oil.

A dryer

Exhaust fumes

Processes

Outputs

Art and scienceItalian artist and inventor Leonardo da Vinci had an inquiring mind and was interested in many different disciplines. Among other things, he was fascinated by the flight of bats and birds. He studied the structure and mechanisms of their wings, the role and placement of their feathers, the shape of their joints, etc. This led him to eventually create various flight devices, such as a helicopter’s rotor (which he called the “flying screw”), a parachute and a type of hang-glider. Leonardo da Vinci

(1452–1519)

15TH AND 16TH CENTURIES ITALY



A C T I V I T I E S 1. Name the overall function of the following technological systems.

a) A stapler. Stapling papers together.

b) A coffee maker. Making coffee.

c) A television. Displaying images and projecting sounds.

d) A bicycle. Allowing a person to get around.

e) A lawnmower. Cutting grass.

2. Name at least two inputs and two outputs of each system in the previous question. Sample answers:

TECHNICAL OBJECT INPUTS OUTPUTS

a) A stapler.

• Staples (unbent).

• Sheets of paper (loose).

• Muscle power.

• Staples (bent).

• Sheets of paper (attached).

• Heat.

b) A coffee maker.

• Ground coffee.

• Water.

• Electricity.

• Coffee (brewed).

• Coffee grounds.

• Coffee smell.

• Heat.

c) A television.

• Signal (received through a cable

or satellite).

• Electricity.

• Images and sound.

• Heat.

• Static electricity.

d) A bicycle.

• Muscle power.

• Air (in tires).

• Lubricant (for mechanical parts).

• Motion.

• Wear on the tires.

• Accumulation of mud and dirt.

e) A lawnmower.

• Grass (uncut).

• Gas or electricity.

• Cut grass.

• Noise.

• Exhaust fumes.

• Heat.



3. Indicate the controls for each of these systems.

a) A stapler. Lever.

b) A coffee maker. Switches.

c) A television. Remote control buttons.

d) A bicycle. Pedals, handlebars, gear shifters, brake levers.

e) A lawnmower. Switches, starter handle.

4. Describe the processes involved in these two systems.

a) A stapler.When the lever is pressed, a stack of papers is pierced by a staple. The

staple is then pressed against a crimper, which forces the staple legs

to bend inwards, holding the papers together.

b) A bicycle.Pedals are connected to the rear wheel by gears and a chain. When the

pedals are turned by a person’s feet, they make the rear wheel spin, moving

the bicycle forward.

5. Complete the diagrams for the following systems.

a) A dishwasher.

Detergent is mixed with water, then sprayed onto dirty dishes

by rotating arms.

Washing dishes.

Dirty

dishes, hot water,

detergent, electricity.

Clean

dishes, dirty

water, heat,

noise.

Control

panel.



b) A car.

c) A cellphone.

Energy from the battery is used to turn voices (and images) into a signal.

This signal is then transmitted by cellphone towers until it reaches

the other person’s phone.

Gas is burned in the engine. The resulting energy is used to

turn the wheels.

Allowing one or more people

to get around.

Allowing two or more people to have

a conversation at a distance.

Chemical

energy (battery),

sound (voice), images.

Driver,

gas, electricity

(spark plugs), motor

oil, air.

Signal

(sent through

cellphone towers).

Motion,

exhaust fumes

(water vapour, carbon

dioxide, carbon

monoxide), heat.

Buttons.

Steering wheel, dashboard, brake

pedal, gas pedal.



The components of a system are the different elements (like parts, mechanisms, devices or machines) that make up a system.

D E F I N I T I O N

A computer has different parts that process data, produce images and sound, cool the processors, etc. Each of these parts is a separate, smaller system within the computer, which is a system in and of itself.

What are the components of a system?What components can we expect to find in a technological system?

7.2

7.2.1

A “car” system Here’s how a complex system can be broken down into smaller systems.

Large systems can be broken down into smaller and smaller subsystems.

Components of a system

Each component has a part to play within the larger system. Let’s look at the braking system. When you press on the brake pedal, you start a mechanism that leads to the brake pads (dark grey) in the calipers (red). The calipers then pinch against the spinning wheel to slow it through friction.

A car, as a system, can be divided into subsystems: electrical system, braking system, etc. Each of these subsystems can, in turn, be divided into parts.

For instance, the braking system is made up of the brake pedal, the brake oil reservoir, the discs or drums, etc. Each of these parts can be broken down until you end up with indivisible parts, like the brake pads.

“Car” system

Electrical system

Engine system

Braking system

Brake calipers

Brake pads

Brake pedal Discs

Suspension system



A C T I V I T I E S 1. Take a look at this lawnmower. Indicate the function of each of the following components.

a) Handle. Steering the lawnmower.

b) Controls. Starting or stopping the engine.

c) Gas tank. Providing fuel to the engine.

d) Rotary blades. Cutting grass.

e) Bag. Holding cut grass.

2. Name the component(s) that perform the following functions in a digital music player and its headphones.

a) Displaying the name of the song you’re listening to. Screen.

b) Producing sound. Headphones.

c) Choosing a song. Buttons.

d) Storing songs. Memory card.

e) Adjusting the volume. Volume button.

3. Match each component of a food processor (left) with its function (right).

a) Switch. • • Starting or stopping the motor.

b) Cord. • • Spinning the blades.

c) Blades. • • Supplying electricity to the device.

d) Motor. • • Holding the chopped food.

e) Reservoir. • • Chopping food.

Handle and controls

Motor (spins the blades

at high speed)

Rotary blades

Bag

Gas tank



4. True or false? If a statement is false, correct it.

a) Every component of a system is also a part.False. A component can be a subsystem made of several parts.

b) A technological system can be divided into subsystems.True.

c) Systems can have parts that serve no use.False. Every element of a system has a job to do.

5. Name at least two subsystems within each of these systems.

6. Name the dishwasher component that performs each of the functions listed. Use the words from the list.

a) Holding the dishes in place. Racks.

b) Drying the dishes. Heating element.

c) Protecting users from burns. Insulation.

d) Heating the water. Heating element.

e) Spraying water and detergent onto the dishes. Spray arms.

f) Controlling the water level in the drum. Float valve.

g) Turning the spray arms. Motor.

SYSTEM SUBSYSTEMS

a) A television.

Sample answers:

• Screen and image system.

• Speakers and sound system.

b) A bicyle.

• Gear shifter (changes speed and transfers motion).

• Braking system.

• Steering system.

Detergent dispenser

Drain hose

Float valve

Heating element

Insulation

Motor

Pump

Racks

Spray arms

Tub



A manufacturing process sheet describes all of the steps that need to be followed to create the parts of a technical object. It also lists the equipment, materials and time required for each step.

D E F I N I T I O N

Manufacturing process sheetYou might have already followed a set of instructions to put together a 3D puzzle or build a spaceship out of blocks. Similarly, people in factories have to follow a step-by-step plan to make products. This way, they can make sure all of the products are identical and are put together properly before they are sent to stores.

What is a manufacturing process sheet? The clue is in the name: a manufacturing process sheet outlines the process and steps to follow for making an object.

7.3

7.3.1

Manufacturing process sheet for a clock On the following page, you will find a manufacturing process sheet. It describes the process for making a clock face, similar to the one below. The clock face is a piece of cardboard with numbers around the edges and a hole for the hands in the middle.

A manufacturing process sheet is an essential document for mass-producing a technical object.

The clock itself is a complex system. If the clock’s designer made it herself, she wouldn’t need a very precise manufacturing process sheet since her clock would be unique. However, if she wanted to mass-produce the clock (make many identical clocks), the process sheet would need to be much more detailed. The system would need to be divided into subsystems so that all components can be accounted for, right down to the single parts.



Manufacturing process sheet for a clock (continued)

MANUFACTURING PROCESS SHEETPart: Clock faceMaterial: White cardboard. 70 mm × 70 mm, 1 mm thick

NO. PROCESS SKETCHEQUIPMENT AND

MATERIALSTIME NEEDED

10 Measuring and marking • Ruler

• Compass

• Protractor

• Pencil

15 min

11 Trace a circle with a diameter of 64 mm (Ø) on the cardboard.

12 Make a small dot on the edge of the circle and write the number 12 below it. Divide the circle into 12 equal sections (30 degrees each), then place 11 other dots. These will indicate the hours.

13 Divide each section into 5 smaller sections (6 degrees each), then draw 4 lines. These will indicate the minutes.

20 Machining and forming • Scissors

• Hole punch

5 min

21 Cut out the circle, making sure to follow the line marked earlier.

22 Punch a hole approximately 4 mm in diameter in the middle of the circle.

30 Finishing • Ruler

• Black medium-tip marker

5 min

31 Remeasure the circle to make sure it is 64 mm in diameter. If this is not the case, correct the piece or discard it.

32 Write the numbers 1 through 11 below the dots. Trace over the number 12 with the marker.

The header contains general information about the part being made.

Each section describes a general step in bold (for example, 10) that has been broken down into a series of more specific steps (for example 11, 12 and 13).

Other manufacturing process sheets are needed to build the rest of the clock: one for the hands, one for the frame, etc. Once all the pieces have been produced, they can be assembled using an assembly sheet as a guide.



How to make a technical object?

The techniques for making a technical object fall under one of five categories: measuring and marking, machining and forming, finishing, assembling and disassembling.

MACHINING AND FORMING

During this step, parts are cut using tools (machining) or are folded to give them the needed shape (forming).

• Place a cutting mat or piece of cardboard on the workspace to protect surfaces. If needed, hold the part being cut in place (for example, using a clamp).

• Cut the parts using the appropriate tool and technique. Cut slowly, making sure you follow the cut lines carefully.

ATTENTION: the edges of metal sheets are sharp! Additionally, tiny pieces of wood (splinters) can get caught under your skin when you handle cut wood!

• Punch holes in the places where parts will be held together by bolts or screws.

• Form parts by folding them. Soft metals and cardboard can be folded fairly easily, but plastic may have to be heated before it can be formed. Harder metals will need to be placed in a vice.

MEASURING AND MARKING

Before creating a technical object, the materials need to be measured carefully and the cut lines need to be marked.

• Measure each part, using the measurements indicated in the manufacturing process sheet. For each measurement, make at least three pencil marks to use as reference points.

• Mark the cut lines by joining the pencil marks. Use:

– a ruler or metre stick to mark straight lines;

– a set square to draw perfect corners;

– a compass or template to draw curves.

• Double-check that the lines of the curve match the measurements in the instructions.

It is important to take precise measurements. They are fundamental to construction.

15

21

Wood block

Hopper location

6

29

30

15

19

19

24

19

1515

15

Bottom

HopperSide

Back

Side

Front edge



How to make a technical object? (continued)

ASSEMBLING

Assembly is the last step in the fabrication process. When assembling parts of an object, it is important to use the appropriate links.

• When choosing a link, consider the materials and assembly type: – glue, nails or soldering can be used for

permanent assemblies;– screws or bolts can be used for non-permanent

assemblies.

• Choose guiding controls (such as hinges or tracks) to allow some parts to move.

• Assemble the parts according to the instructions.

DISASSEMBLING

Sometimes an object may need to be partially or completely disassembled. Disassembly can make an object easier to transport or store in a smaller space. For an object to be disassembled without being destroyed, it needs to be held together with non-permanent links.

• Disassemble the object section by section.

• Place the parts of each section in bags or small containers. As needed, write the names and uses of each part on the outside of the container.

During assembly, an object will gradually start to take shape.

FINISHING

Once all of the parts are the right size and shape, they can be moved to the delicate finishing stage.

• Remeasure the parts to make sure that their dimensions (length, width and height) match up with what’s on the process sheet.

• File metal or sand pieces of wood as needed. Filing and sanding can smooth rough surfaces and remove bits of extra material if the dimensions are not quite right or the parts have not been properly cut.

• Sand wood with the grain to smooth the surface. This will make adding paint and varnish easier.

• Stain, paint or varnish surfaces as needed. This can also be done after assembly, but only if all of the surfaces are easily accessible.



A C T I V I T I E S 1. This manufacturing process sheet outlines the process for making a water holder for a planter out of a 2-L plastic bottle.

a) Fill in the blanks.

b) To complete the planter, you need a container to hold the soil. You also need to install an irrigation system to carry the water from the container to the soil. How many extra manufacturing process sheets do you need to complete the technological system? Explain your answer. Two other manufacturing process sheets: one for the container that will hold

the soil and another for the irrigation system.

MANUFACTURING PROCESS SHEETPart: Water holderMaterial: 2-L plastic bottle

NO. PROCESS SKETCH EQUIPMENT AND MATERIALS TIME NEEDED

10 Measuring and marking

• Marker

• Ruler

5 min

11 Mark a line around the bottle 12 cm from the bottom.

20 Cutting • Scissors 10 min

21Cut along the cut line.

30 Finishing • Sanding block

• Emery paper

20 min

31 Sand the edge of the container to smooth it.

32

Paint the container green.

• Green paint

• Paintbrush

12 cm



2. Complete the following text using the words provided.

a) The manufacturing process sheet is an important tool in the industrial field.

It allows people to produce many identical objects:

a process known as mass production. It also outlines

how much time each step

takes, allowing people to plan how long it will take

to produce a number of objects.

b) For each step, a process sheet must provide a detailed description of the job to do and how long it will take, as well as the material and equipment needed.

c) Once all of the manufacturing process sheets have been written and the parts have been made, all that needs to be done

is to create the assembly sheet and assemble the parts.

3. This manufacturing process sheet shows the process for making an origami truck. Look at the sheet, then answer the question.

MANUFACTURING PROCESS SHEETPart: Paper truckMaterial: A square sheet of white paper


10 Measuring and marking • Sheet of paper

• Pencil

• Ruler

2 min

11 Draw a dotted line through the centre of the paper.

12 Draw a dotted line on the outer third of each half of the paper.

Assemble

Assembly

Equipment

Identical

Job

Manufacturing process sheet

Mass

Material

Parts

Plan

Step

Time



Are the steps to do clear and sufficient? If not, how would you correct the problem?Sample answer: A better explanation is needed on how to fold the sheet’s corners

in steps 22 and 23. Show how to mark the two dotted vertical lines for the pleat

in step 24.


20 Folding • Sheet of paper

• Ruler

5 min

21 Fold each side along the outer dotted lines.

22 Fold the four corners so that they make triangles.

23 Fold the tip of each triangle back towards the middle.

24 Pleat the paper once.

25 Fold the paper in half along the dotted line.

26 Fold the upper left corner towards the inside.

30 Finishing • Sheet of paper

• Black marker

• Ruler

1 min

31 Draw the windows on the truck.



Energy is the capacity to produce a change. It describes an object’s ability to produce a movement, release heat or emit rays (like light, for example).

A useful form of energy is a form of energy that humans can use to meet their needs.

D E F I N I T I O N

D E F I N I T I O N

For most of history, humans have wanted to use the energy available to them. Over time, different techniques have been developed to harness and use various forms of energy. Little by little, humans have designed machines and systems to transform some forms of energy into other, more useful, forms of energy.

What is energy? In Chapter 5, we defined energy as “the capacity to produce a change.” Here is a more specific definition.

7.4

7.4.1

What is a useful form of energy? In Chapter 5, you learned about natural energy sources. Humans cannot always use natural energy in its direct form. It often has to be transformed into a more useful form.

For example, wind cannot heat our homes. However, we can convert wind energy into electrical energy, then transport the electrical energy to our homes and reconvert it to thermal energy (heat).

7.4.2

Energy transformations Natural energy sources, p. 147

Renewable and non-renewable energy resources, p. 152

What is a motor?

A motor is a system that can use energy from electricity, a combustible or a battery to do a job like heating, rotating, pushing, pulling, etc. In short, it transforms energy into thermal or mechanical energy. In a vehicle, the motor uses chemical energy from gasoline to rotate the wheels.



Forms of useful energy Here are four forms of useful energy.

Humans mainly use four forms of energy. Many different natural energy sources can be transformed into one or more forms of useful energy.

How do batteries work?

A battery is a container that stores two chemical substances. One substance corresponds to the positive terminal (+) and the other, to the negative terminal (–). When the two terminals are linked to electrodes (for example, in an electrical circuit), the two chemical substances react and produce electricity. The chemical energy in batteries is transformed into electrical energy.

Mechanical energy. Mechanical energy comes from the motion of an object or its position in space.Many technological systems are designed to create motion or work because of motion. In a fan, for example, the rotating blades move air quickly. As a result, they can warm, cool or ventilate a room.

Thermal energy. Thermal energy comes from the agitation of particles in matter.It is usually produced from combustion (of wood, gasoline, gas, etc.). It can be transformed or used directly. For example, thermal energy heats air in a heater, heats water in a water heater and cooks food in an oven.

Electrical energy. Electrical energy is the energy associated with the movement of electricity.It can be produced from most energy sources. Additionally, it can be transformed into many other forms of energy. Electricity can be carried over long distances.

Luminous energy. Luminous energy is carried by light.There are many sources of light, most of which involve some sort of transformation of energy. For example, electrical energy is transformed into luminous energy in lamps, signs, etc.



Examples of energy transformations Here are some examples of how energy is transformed from natural sources.

An energy transformation is the conversion of one form of energy into another.

D E F I N I T I O N

What are energy transformations?How is energy transformed? How can we get the forms of energy that we need?

7.4.3

Solar energy. Photovoltaic solar panels are used to transform solar energy into electricity.Thermal solar panels can also be used to convert solar energy into heat.

• Thermal solar panels capture solar radiation directly through tubes that contain a gas or a liquid (for example, water).

• Solar energy is transmitted to the water as heat (thermal power).

• The heated water is then piped to various parts of a house (a water heater, for example).

Thermal solar panel

Water heater

Photovoltaic solar panel



B Blade

A Wind

Biomass made up of decayed organic waste

Examples of energy transformations (continued)

A hydroelectric power plant

A wind turbine

B Turbine

A Hydraulic energy B Mechanical energy C Electrical energy

A Wind

energy

B

Mechanical energy

C

Electrical energy

Wind energy. Wind energy is mostly used to produce electrical energy through wind turbines. This is not a direct transformation. The wind produces mechanical energy as it rotates the blades of the turbine, then an alternator converts the mechanical energy into electrical energy.

Hydraulic energy. There are many techniques for turning hydraulic energy, which comes from the motion of water, into other forms of energy. Most of the time, hydraulic energy is converted into electrical energy through turbines and alternators (devices that generate electricity) in hydroelectric power plants.

Biomass. Different types of biomass, like wood and peat, essentially act as combustibles. Biomass can sometimes replace fossil fuels (see next page). Burning biomass produces thermal energy, which can be used directly or transformed into electricity.

C Alternator

A Water Dam

C Alternator



Fossil energy. Fossil energy, which comes from oil, coal and natural gas, is transformed into thermal energy through combustion. This is why we say that oil and gas are combustible. For example, a gas engine transforms fossil energy into thermal energy, then mechanical energy. Fossil energy is also used in thermal power plants to produce electricity.

Nuclear energy. Since the 1960s, nuclear energy has been used to produce energy in nuclear power plants. Nuclear reactions produce radiation that is transformed into thermal energy. Like in a thermal power plant, this energy moves a turbine, which moves an alternator (electrical energy).

The examples above show that there are many different ways to convert energy. In Québec, we mostly use hydraulic energy to produce electricity.

Examples of energy transformations (continued)

Thermal power plant

A nuclear plant

A Combustible

A Uranium and reactor

B Boiler

Vapour

Vapour Water vapour

D Alternator

D Alternator

C Turbine

C Turbine

B Heat (water under pressure)

A Fossil energy B Thermal energy C Mechanical energy D Electrical energy

A Nuclear energy B Thermal energy C Mechanical energy D Electrical energy



A C T I V I T I E S 1. Match each form of energy (left) with the main change(s) it produces (right).

a) Mechanical energy. • • Motion.

b) Thermal energy. • • Heat.

c) Luminous energy. • • Radiation.

d) Electrical energy. •

2. Name the form of useful energy used in each situation. Underline the word that indicates the form of energy.

a) A hamster spins its wheel as it runs. Mechanical energy.

b) Alice burned herself when she touched the flame of the candle on her birthday cake. Thermal energy.

c) Taleb plugs his digital music player into his computer to charge it. Electrical energy.

d) Edward is watching the fireflies flashing their lights in the dark. Luminous energy.

3. Name the form of useful energy described in each statement.

a) It comes from the movement of electricity. Electrical energy.

b) It is carried by light. Luminous energy.

c) It comes from the agitation of particles in matter. Thermal energy.

d) It comes from the motion of an object or its position in space. Mechanical energy.

4. Check the situations that show an energy transformation.

a) You place a pot of water on the stove. After a few minutes, the lid of the pot starts to rattle.

b) You heat leftover food in the microwave.

c) You listen to music on the radio.

d) When you look in a mirror, light is reflected off its surface.



6. Name the form of starting energy used by each of these objects.

a) A flashlight. Chemical energy.

b) A BBQ. Fossil energy.

c) A car. Fossil energy.

d) A solar cell panel. Solar (or luminous) energy.

e) An incandescent light bulb. Electrical energy.

f) A wood stove. Biomass energy.

g) A bicycle. Biomass energy.

7. Name the useful energy produced during each step of these energy transformation sequences.

a) A bicycle.

b) A cordless drill.

TECHNICAL OBJECT STARTING ENERGY END ENERGY

a) A toaster. Electrical energy. Thermal energy.

b) A solar cell panel. Luminous energy (Sun). Electrical energy.

c) A car. Thermal energy (gas). Mechanical energy.

d) A lamp. Electrical energy. Luminous energy.

Step 1: I pedal my bicycle. Mechanical energy.

Step 2: My bicycle’s generator produces energy. Electrical energy.

Step 3: I turn on the light on the front of my bicycle. Luminous energy.

Step 1: I charge my cordless drill. Chemical energy.

Step 2: I turn on my cordless drill. Mechanical energy.

Step 3: I use the drill to attach the back panel to my new bookshelf. Mechanical energy.

5. The following systems are performing energy transformations. Indicate the form of starting energy and end energy (useful energy) produced in each case.

(Cyclist’s muscle power).



Chapter 7 Review1. Complete the diagram of the following technological system: a barbecue.

2. A bicycle is a technological system that is made up of subsystems. Name the function of the following subsystems.

SUBSYSTEM FUNCTION

a) Braking system.Slowing or stopping the bicycle.

b) Steering system.Changing the direction of movement.

c) Transmission system.Transmitting the motion of the pedals to the rear wheel.

Propane gas is burned.

The resulting thermal energy

is used to cook

the food.

Cook food.

Propane

gas,

uncooked food.

Cooked

food, carbon

dioxide,

heat, scent,

smoke, greasy

residue.

Ignition button, control buttons,

gas supply valve.



3. Does a bicycle perform energy transformations? Explain your answer. No. The starting energy is provided by the cyclist’s muscular power

on the pedals, which is a type of mechanical energy. The end energy has to do

with the movement of the bicycle, which is also a type of mechanical energy.

This means there is no energy transformation.

4. Read the text below, then answer the questions.

a) What is the function of the life support system?To manage the water cycle on the International Space Station.

b) What are the inputs of this system?Dirty water, urine and sweat produced by the crew.

c) What are the outputs of this system?Drinkable water, oxygen and hydrogen (waste).

The International Space Station has an interesting life support system. It recovers dirty water, urine and sweat from the crew, then treats it so it becomes drinkable again. Part of the recovered water is also separated through hydrolysis to maintain oxygen levels in the air. The hydrogen produced by this process is expelled from the space station along with the carbon dioxide exhaled by the astronauts.



5. Complete this manufacturing process sheet, which is used for building a small gear.

MANUFACTURING PROCESS SHEETPart: Small gear Material: 15 cm × 15 cm sheet of aluminum-carbon fibre blend

NO. PROCESS SKETCHEquipment and

materials

Time

needed

10 Measuring and marking • Compass

• Protractor

• Ruler

• Marker

20 min

11 Draw three circles: one 8.6 cm

(wheel), one 10 cm (teeth) and one 7.5 cm (inside).

12 Draw 7 teeth that are 7 mm deep every 10° between the two largest circles.

13 Draw two strips measuring 1 cm wide that meet at a 90° angle in the centre.

14 Draw a circle approximately 5 mm in diameter at the centre.

20 Cutting and drilling • Hacksaw

• Vice

20 min

21 Cut out the teeth using

a hacksaw.

22 Punch a hole at the centre of the wheel.

• Drill and bit

23 Cut out the inside quarters of the wheel.

• Drill

• Hacksaw or scroll saw with metal blade

• Vice

30 Finishing • Varnish

• Paintbrushes

5 min

31 Varnish the gear to give it a smooth finish.

8.6 cm7.5 cm10 cm

1 cm

Ø 5 mm



chapter technological systems · chapter 7 what is a system? technological systems in technology,...

Documents