DUAL FOCUS
2
SECONDARY EDUCATION teChNOlOgy
aND DigitIzAtiON ANDA lUSIA
CONTENTS
1. An introduction to technology 7
1 Humanity advances with technology • 2 Consequences of technological activity • 3 The impact of technological activity on the environment • 4 The process of resolving technological problem • 5 The workshop and technology work • The final challenge
2. Technical design 13
1 Introduction to technical design • 2 Technical drawing tools • 3 Techniques for drawing lines, curves and angles • 4 Views of an object • 5 Perspectives • 6 Paper in technical design • 7 Preparing sketches and croquis • 8 Use of technical design software • 9 Digital graphics with Inkscape • The final challenge
3. Technical materials. Wood and metal 21
1 Materials • 2 Properties of materials • 3 Wood • 4 What do we use wood for? • 5 Woodworking tools • 6 Metals • 7 Ferrous metals • 8 Nonferrous metals • 9 Metalworking tools • 10 Metalwork • The final challenge
4. Structures 31
1 Structures • 2 Forces • 3 Structural components • 4 Types of structures • 5 Profiles and trusses • 6 Mechanisms • The final challenge
5. Electricity 39
1 An electric circuit and its components • 2 Properties of the electric circuit • 3 Energy sources • 4 Protoboards and Tinkercad circuits • 5 Energy efficiency and energy labels• The final challenge
6. Computer hardware and networks ......................................... 47
1 Computer components • 2 Central process unit • 3 Peripherals • 4 Discovering computer networks • The final challenge
7. Basic office automation ................... 55
1 Word processors • 2 Electronic presentations • 3 Electronic presentations with PowerPoint • 4 Electronic presentations with Genially • 5 Electronic presentations with Canva • The final challenge
8. Internet 63
1 What is the Internet? • 2 Internet operation and protocols • 3 The web and the HTTP protocol • 4 Advantages and risks of the internet • 5 Email • 6 The people network • 7 The Internet of Things • 8 Cloud computing • 9 Legislation and network security • The final challenge
9. Introduction to programming 71
1 Computer language • 2 Scratch • 3 Introduction to robotics • 4 Robot architecture • 5 Control systems • 6 Robot programming with micro:bit • The final challenge
4 Structures
Design
Structures
STRUCTURES
Build a structure for wind turbine
SCAN THE CODE TO FIND OUT ABOUT THE CHALLENGE
Forces
Inspiration in nature
Structural components
Measurement instruments and units
Loads and balance
Types of forces and loads
Types of stress
Elements
Failures
Types
Profiles and trusses
Profiles
Trusses
Levers
Mass structures
Framed structures
Laminated structures
Triangulated structures
Vaulted structures
Hanging or suspended structure
FOCUS O N ENGLISH
Listening and speaking
Listen and repeat the words to improve your pronunciation.
Mechanisms
Pulley and gear systems
Pulley and hoists
The inclined plane
Reading and Writing
Use the branches of the outline to create three sentences about the structures, the forces and the different kind of mechanisms.
Structures 1
Structures are complex objects meant to support certain loads (such as a house). Three conditions are considered in the design of a structure:
• The structure must be stable and maintained in static equilibrium.
• The design must ensure that its parts don’t deform.
• The structure must be resistant and withstand different forces.
A structure’s design
A structure is made up of a series of solid elements, joined and attached together to support all kinds of loads.
Natural structures
Observing different structures in nature allowed us to learn that the correct distribution of forces and weights are key to how natural structures are sustained.
Copying natural constructions
Nature has inspired the design of many structures. This explains the development of biomimicry, a field of science that studies biological structures to solve human problems by looking at nature. For example, in Harare (Zimbabwe), an air conditioning system has been created based on how termites cool their mounds using air currents.
Forces 2
How are humans inspired by nature?
What science imitates natural structures?
1 Make a list of elements and constructions that can be based on natural structures.
What are forces?
Forces are pushes or pulls characterised by their value or intensity, or by their orientation. Forces make changes to bodies: they can change their shape (deforming them) or their movement (changing speed or direction).
How are they measured?
There are several instruments for measuring forces, such as scales or the dynamometer, which is based on the ability of a spring to extend proportionally to the force applied.
Units of measurement
Mass is measured in kilograms (kg) in the International System (SI). Forces are derived from mass, so the International System uses the newton (N), defined according to the expression: 1 N = 1 kg · m/s2.
How do forces influence stability?
What types are there?
kg Ring Spring Mobile band for marking the weight Extendable graduated ruler with the spring Dynamometer
A termite mound built by termites. 24°C
Air flow inside the building in Harare based on a termite mound.
Loads and balance of an object
A balanced structure is affected by multiple forces. All forces acting on it need to add up to zero (otherwise, the body will be subjected to acceleration). The forces that appear due to the weight the structure supports are called loads. Loads can be classified into static (that do not change over time), dynamic (that can change over time) and accidental (such as those due to meteorological phenomena).
The centre of gravity: a key concept for stability
An object or structure is stable when its mass distribution is balanced when the forces of gravity act on it. The centre of gravity is defined as a geometrical point representative in the body of an object in which we imagine all its mass is concentrated.
For example, the centre of gravity of a symmetrical body is the geometrical point at which all the diagonal lines that join the opposing vertices cross. In figures lacking symmetry, this point can be located out of the body, which indicates a lack of stability.
Types of forces and loads
There are two criteria for classifying forces and loads. According to their duration and magnitude, they can be fixed (constant magnitude and direction) or variable (changing magnitude and direction). And, depending on how they are applied, they can be concentrated (located at one point of a surface) or distributed (disseminated over a surface).
In the example of deformation shown, you can see that with more sand in the mound, the load at the centre increases, which is where the deformation will be greater if the structure is not very resistant.
Loads created by forces
When a set of forces acts on an object, the object is deformed by internal forces known as stresses There are five types of stresses:
• Tension: two forces stretch the body and therefore increase its length.
• Compression: forces act on the body and shorten it and make it wider.
• Bending: forces bend or curve a body.
• Torsion: two rotational objects applied in opposite directions twist and object.
• Shearing: an object is cut by two forces that act on it in different directions.
Types of stress
Centre of gravity
Circle Cube Triangle Asymmetrical shape
Deformation
Representation of the weight of the sand as it accumulates. Sand mound
Reaction of the structure to support the weight of the sand.
Distribution and effect of a sand mound on a platform.
Vocabulary
Tension, bending, torsion, compression, shearing.
2 If the mass of a wind turbine is 2 kilograms, what is its weight, that is, the force with which the Earth attracts it, if the acceleration due to gravity is g = 9.8 m/s 2?
Structural components 3
Structural elements
A structure is made up of different elements, and each of them has its own function, so that not all of the elements are subjected to the same stresses. Some of the most common ones are:
• Foundations: these transmit structural loads to the ground.
• Arches: curved frames in which the forces supported are distributed between the elements, which are subjected to compression.
• Braces: steel cables used to provide rigidity to the structure and increase its resistance. Subjected to tension.
• Pillars and columns: vertical elements of the structure. They are mainly subjected to compression.
• Beams: horizontal elements of the structure that support the load between two support points. Mainly subjected to bending.
Structural failures
The failure or malfunction of a system is inherent to human activity. Therefore, it is important to carry out preventive maintenance work and to be careful and precise in the design of the structure. The main causes of failures are:
• Material fatigue: structures are constantly subjected to forces and loads. If these loads move, vibrations are sent to the structure, meaning that the material from which the structure is made is subjected to more stress and wears down more quickly.
• Rusting and corrosion: all materials rust, which often leads to corrosion, resulting in a loss of mass in the material affected.
• Incorrect structural design: structures are affected by many factors, such as the optimal selection of materials, calculations, location, how the elements are arranged, and even the assembly of the elements, as well as other parameters. If mistakes are made in the planning and design process, structural failures will appear in time.
How can a structure support its loads? What can cause structural failure?
Vocabulary
Foundations, arches, braces, pillars, columns, beams, material fatigue, rusting, corrosion, incorrect structural design.
3 Aside from the reasons mentioned above, what else can cause a structure to fail?
Foundations
Pillars and columns
Arches
Braces
Beams
4
Types of structures
All structures can be classified into the following types:
• Mass structures: they use the accumulations of natural materials to provide support, based on their strength, resistance and permanence.
• Framed structures: they use resistant elements such as vertical pillars and columns crossed by horizontal beams.
• Laminated structures: they provide coverage and protection. They tend to be light and fragile.
• Hanging or suspended structures: they are based on the use of braces and cables to support solid structural elements.
• Triangulated structures: making triangles is the most effective way to make structures more rigid.
• Vaulted structures: arches and vaults are complex and expensive to build, but are useful for solving architectural problems.
Profiles and trusses 5
What are the uses of the different structures?
Can you give any examples? Why have profiles got different shapes?
What do we use trusses for?
Profiles
Profiles are the commercial shapes in which steel, aluminium and other materials are generally supplied. These special shapes provide improved strength using as little material as possible.
Vocabulary
Open profiles, closed profiles, trusses, bracket.
Trusses
Trusses are one of the systems used to create structures from simple elements such as profiles. Trusses are built by making triangular shapes and joining the profiles and bars together using brackets. This creates a structure that is light but resistant to being deformed, and optimal for reinforcing roofs or bridges.
A simple truss design used in a bridge The structural design of an industrial unit using trusses
4 Build open and closed profiles using newspaper, cardboard from packaging or scrap notebook paper and attaching them with adhesive tape. Use the same material for all the profiles. You can fold the material but not cut it. After they are built, test them by putting weight on them. Which one supports more weight? Why?
Mass structures Framed structures
Laminated structures Vaulted structures
Mechanisms 6
A machine is any device that allows us to work faster and with less effort. All machines are made up of mechanisms. Every mechanism, no matter how complex it may be, is in turn based on simple elements, called simple mechanisms or machines. Some examples are the lever, the pulley and the inclined plane.
A lever is a rigid bar that oscillates around a support point.
A pulley is made up of a wheel with a channel through it for a rope.
Levers
A lever is a rigid bar whose function is to transmit force and motion. The lever rests on a bearing point (fulcrum) and the force applied on it moves the opposite arm. The arm supporting the force is called the driving arm, and the one holding the load is called the resistance arm. The force can be calculated with the following formula:
F is the driving force (in newtons)
d is the driving arm (in metres)
F Ò d = P Ò D
P is the resistance force (in newtons)
D is the resistance arm (in metres)
There are three types of lever: type 1 (multiplying mechanism), type 2 (multiplying mechanism) and type 3 (reducing mechanism).
Pulley and gear systems
They transmit a rotary motion to the connected arm. Types: Pulleys
A wheel with an axle (driver pulley) joined by a belt to another wheel (driven pulley); the former transmits the rotary motion to the latter. Depending on the relative diameter of the pulleys, the system will be multiplier (increasing the speed of the driven pulley) or reducer (decreasing it).
Gears
Gears are used to transmit a rotary motion along one or several stages of gears. Their wheels must mesh, which is only achieved if they have the same ratio between their diameter and number of teeth (the module).
What mechanisms are used to transmit force?
Types of levers
An inclined plane allows heavy objects to be lifted by pushing them.
Pulleys and hoists
A pulley is nothing more than a wheel that rotates around a central axis and that has a channel or groove on its edge for a rope. Its function is the same as a lever: to transmit movement by modifying forces.
Types of pulleys
There are two types of pulleys:
• Fixed pulleys: They are anchored to a surface, so they can only rotate. The load is placed at one end of the rope and the force is applied at the other. In these pulleys, the force that we have to apply to support the load is equal to it. They don’t reduce the effort we have to make, but they do change the direction of the force. Instead of ‘pulling up’ to raise a weight, we ‘pull down’, which is much more comfortable.
• Movable pulleys: They are held by the rope itself and move with the load, they do not have any axis around which to rotate. These pulleys do reduce the force that we have to apply to hold or move the load by half, but they have the disadvantage that they do not modify the direction of the force, that is, we have to continue ‘pulling up’ to lift a load.
To take advantage of both types of pulleys, we use combinations of both, they are called hoists.
The inclined plane
The inclined plane divides the weight of the load into two forces, so that the force we have to overcome to lift the load is smaller.
Look at the drawing on the bottom. Without using the inclined plane, the entire weight (represented by the blue arrow) would have to be supported. When using an inclined plane, the effort used is only part of the weight of the load. The smaller the angle of the plane, the smaller the force necessary to move the object. This advantage has a drawback: the distance that has to be travelled is greater.
5 With which system do you think we will have to make less effort? Explain your answer.
Vocabulary
Lever, pulley, inclined plane, driving arm, resistance arm, driver pulley, driven pulley, module, fixed pulleys, movable pulleys, hoists.
The force to overcome to achieve motion
Inclined planes
The final challenge
Take action!
Building a structure for a wind turbine
This involves using everyday materials to build a wide based structure to house the circuit and a tower to support the wind turbine.
The main idea is to use long, thin elements to build the structure, which do not necessarily have to be resistant by themselves.
STEP 1
Draw a sketch
• We recommend using a pencil and paper and drawing freehand sketches to help you have a clearer idea of the structure you will design.
Analyse the materials
SCAN THIS CODE TO CONSULT THE GLOSSARY FOR THIS
STEP 3
• Before starting, analyse which materials you think will hold the most weight and why.
STEP 4
STEP2
Create the structure
• You could use straws, spaghetti, rolled paper ... To join them and create the structure, you can use paper, tape electrical tape, hot melted glue or liquid glue.
Building the final structure
• Prepare the necessary material by calculating the quantity and measurements. Use a plywood or MDF board as a base.
STEP 5
Test
• Finally, check the structural integrity of your design.
• How many straws, pieces of spaghetti, rolls did you use?
• Could the structure serve it purpose using less?
• What design elements can you improve?
Straws
Recycled paper rolls
5 Electricity
Generators
Conductors
Concept and components
Electric current
ELECTRICITY
Properties
Protoboards
Tinkercad circuits
Loads
Control and protection elements
Symbols
Resistance Power
Connections
Unraveling circuits
SCAN THE CODE TO FIND OUT ABOUT THE CHALLENGE
Cells and batteries, alternators, power supplies
Electric current
Light and heat emitters, motion generators, other
Ohm’s law
In series
In parallel
Renewable
Sources
Non-renewable
Solar, wind, geothermal, biomass, hydraulic
Coal, petroleum, natural gas, nuclear energy
Energy
Energy efficiency
Energy labels
FOCUS O N ENGLISH
Listening and speaking
Listen and repeat the words to improve your pronunciation.
Reading and Writing
Use the branches of the outline to create three sentences about the elements of an electric circuit, nonrenewable energy sources and energy efficiency.
An electric circuit and its components 1
An electric circuit is a closed path made of materials that conduct electricity, in which some components are connected by wires through which electric charges can flow.
These components are generators, conductors, loads, control elements and protection elements.
Generator
Provides the energy for the electric charges which move around the circuit. It is an essential element and can be classified as:
• Batteries: contain chemical substances that generate electricity when they react. When these substances allow the reaction to be reversed, they are called rechargeable batteries.
• Alternators: alternating current machines that generate electrical energy in the form of waves.
• Power supplies: electronic devices that transform alternating current into another form of electrical energy, such as direct current. The energy measurement (charge difference) is known as voltage or electric potential. This magnitude indicates the amount of energy supplied to each electric charge. It is measured in volts (V).
Conductors
Conductors allow electricity to flow from the generator to the loads. In contrast, insulators do not allow electricity to pass.
Electric current is the movement of electric charge along a conductor when it is connected in a closed circuit with a generator. The charges move, creating a flow of electric current through the conductors.
To find out if the flow is low or high, we use the electric current, which is the measure of the number of charges that pass through a particular point of the circuit in a unit of time. It is measured in amperes (A).
Loads
Elements that receive and transform electrical energy. They all have a common property called electrical resistance, which is the opposition of the materials to the flow of current. The most common ones are:
• Light emitters. They transform electrical energy into light, like lamps. Nowadays, light-emitting diodes (LEDs) are commonly used to provide lighting. LEDs are made from semiconducting materials and use very little electricity.
1 Is air an insulator or a conductor?
2 Look up the meaning of lightning bolt.
Which elements are used to make an electrical circuit? Which ones are obligatory?
Remember
Direct current: provided by batteries. Its value is constant.
Alternating current: flows through the power grid and reaches homes. Obtained from alternators. Its value is variable.
Calculating voltage and current
Voltage = Energy ; V = E Electric charge Q
E is the energy expressed in joules (J), Q is the electric charge in coulombs (C) and V is the voltage in volts (V).
Electric current = Charge ; I = Q Time T
Vocabulary
Electric circuit, generator, conductor, load, battery, alternator, voltage, electric current.
• Heat emitting elements. They transform electric current into heat in three different ways:
– By conduction, when two bodies at different temperatures come into contact. For example, a clothes iron.
– By convection, through a fluid (liquid or gas) that conducts heat to places with a different temperature, like a hair dryer.
– By radiation, due to the internal temperature of a body. This is the case with infrared, halogen, or quartz heaters, etc.
• Motors and elements that move. These are rotary machines that can generate electrical energy from mechanical energy. This is the case for electric motors, where the energy is obtained from the forces generated by the copper conductors of the motor as they move inside the magnetic field generated by the magnets of the motor. The most commonly used ones in the technology workshop are direct current motors. There are also motors in the pumps of washing machines and dishwashers, in blenders, juicers, and in DVD readers, some of which use direct current and some alternating current.
• Other loads. There are other types of loads that transform electrical energy into other forms of energy. For example, speakers, buzzers and bells, electromagnetic relays, etc.
Control and protection elements
These components allow or stop current from flowing through all or part of a circuit. There are three types:
• Switches: they open or close the circuit. For example, light switches.
• Push buttons: they open or close a circuit when pushed, as in a doorbell. There are two types: normally open (N.O.) and normally closed (N.C.).
• Multiway switches: when they change position, they close the open circuit and open the closed circuit.
Symbols
As in most technical activities, making a drawing or diagram is important to define electric circuits. To interpret them correctly, it is necessary to know the symbols used for the components of the circuit. Each component of an electric circuit has a symbol associated with it in the diagram. For example, the symbol of a battery is + –and the symbol of an alternator is
Vocabulary
Wires, flow, waves, devices, insulators, charges, lighting, semiconducting, rotary machines, pumps.
Open circuit, closed circuit
Closed circuit: lightbulb on.
Open circuit: lightbulb off.
A circuit will be closed if all of its elements are connected and electric current flows through them. Instead, if it is open, current will not flow through it.
3 Make a table in your notebook with a classification of the different types of loads you have studied. Indicate the energy transformations that take place in each one.
4 Draw the symbols of a switch and a multyway switch.
Electric motor
Electromagnetic relay
Speaker
Properties of the electric circuit 2
Resistance
This is the difficulty that electric current encounters to flow through an object, and depends on its composition and dimensions. It is expressed in ohms (Ω). According to this opposition materials are classified into conductors, insulators, semiconductors and superconductors.
In 1822, the German scientist George Simon Ohm stated Ohm’s law: the current in a circuit is directly proportional to the voltage across its ends and inversely proportional to the resistance of the circuit.
The value of the voltage will depend on the battery or power supply; given this value, the current will be low if the resistance of the circuit is high, and high if the resistance is low.
Power
This is the amount of energy used in a period of time. It is measured in watts (W), defined as joules used per second (1 W = 1 J/s). The unit used for electrical energy is the kilowatt-hour (kWh).
Connections
Electric circuits are made up of more than one load, connected in different ways to form different types of circuits:
• Series circuits. The loads are connected together one after another. If one stops working the rest will stop working too, as the current will not be able to flow.
Magnitude
Explanation Formula
Equivalent resistance Sum of the resistances in the circuit.
Voltage
The sum of the voltages of the different resistances is the same as the voltage of the generator.
Current It is the same for all the elements of the circuit. I
In
• Parallel circuits. The loads are connected to each other and to the voltage of the generator. The current can flow through more than one path.
Magnitude Explanation Formula
Equivalent resistance
Voltage
Current
Its value is the inverse of the sum of the inverse values of each of the resistances of the circuit.
The voltage is the same for all the elements connected in parallel.
The current through each branch of the circuit will depend on the resistance value for that branch. The current provided by the battery will be the sum of all the currents through the branches.
Write down the three different equations used to express Ohm’s law. For each one, identify the variable to be calculated and show which elements you need to do so.
law
Vocabulary
Resistivity, equivalent, watts, inversely proportional, power supply, branch.
5 What current will flow through a 90 Ω bulb when connected to a 4.5 V battery?
6 Show the steps needed to solve a parallel circuit and a series circuit. In both circuits, use two 15 k Ω and 5 k Ω resistances and a 5 V battery.
7 Practice making circuits with the virtual kit provided in anayaeducacion. es. You can also work with the virtual laboratory for Ohm’s law.
Energy sources 3
Can you tell between renewable and non-renewable energies?
List all the renewable and no renewable energy sources you know.
There are two types of energy sources: primary sources, which include sources available in nature before transformation, and secondary sources, obtained from transforming a primary source, which can be stored, transported and used.
As well as coming from primary or secondary sources, energy can be classified as renewable or non-renewable. Both types are used to generate electricity.
Renewable energies
These are energy sources that do not run out when we use them.
• Solar energy. It reaches us in the form of electromagnetic radiation as visible light, infrared radiation and ultraviolet radiation. It is used for lighting, climate control, and other everyday tasks.
• Wind energy. It is obtained from the wind; in reality it comes from the Sun heating the air. It is obtained using windmills which are installed in wind farms and generate electric energy.
• Geothermal energy. It comes from the internal heat of the Earth. It is used for heating systems and to generate electricity.
• Energy from biomass. It is obtained from organic material (plants or animals) and from transformed products. It is burned (to obtain electric energy and heat) or transformed (to obtain biodiesel).
• Hydraulic energy. This is the energy contained in water, manifested in different ways, especially as kinetic energy. It is used in hydroelectric power stations, tidal power stations (using energy from tides) and wave power stations (movement of waves).
Non-renewable energies
They run out as they are used: they do not regenerate, or do so at a slow rate.
• Coal. It is a fossil fuel of plant origin used in industry.
• Petroleum. Of marine origin, it is used to obtain fuels and to produce electrical energy.
• Natural gas. A mixture of hydrocarbons of fossil origin. It is the least pollutant one. Used for heating or cooking.
• Nuclear energy. Obtained from the fission, or breakdown, of uranium-235 atoms, which release energy when broken. It is used to produce electrical energy.
Vocabulary
Resources, run out, infrared, radiation, ultraviolet radiation, windmill, heating system, tidal power stations, hydrocarbons, fission.
Did you know?
Petroleum and natural gas come from a heterogeneous mixture of hydrocarbons. They are different only in that natural gas is in gaseous state.
The nucleus decomposes into smaller nuclei
Energy is released, as well as neutrons that hit other heavy nuclei
8 List the existing types of energy.
9 Create a diagram or mind map to categorize the different energy sources you have studied.
Nuclear fission
Neutron
Heavy nucleus
Protoboards and Tinkercad circuits 4
Protoboards
A protoboard or breadboard is a piece of plastic with small holes that are electrically connected to each other. It allows you to connect electrical and electronic components to test circuits.
Along each side of a typical protoboard there are two rows of holes, one negative and the other positive. All the holes on the same row are electrically connected.
In the central area of the board there are columns of five holes connected to each other; electronic components connected in the same row will be electrically connected.
Tinkercad circuits
Tinkercad is a free web app for designing and simulating electronic circuits.
To get started with Tinkercad you must:
• Go to https://www.tinkercad.com/ and click on Join Now to sign up.
• You can either sign up for a class as a student or register by creating a personal account.
• Choose the Circuits option from the menu on the left-hand side of the screen.
• Click on Create new circuit.
• Select the components from the side-bar menu Components: Basic and drag them to the working area in the centre.
• A tab will pop up every time you click on a component, where you can name the part and add an electrical value.
Important features:
• Measuring tools
• Start simulation button
Can you name one advantage of using a breadboard over soldering when working on electronic projects?
Vocabulary
Breadboard, soldering, simulating, drag, tab.
10 What are the rows of holes on the sides typically used for?
11 If you wanted to connect two components on a breadboard but they aren’t on the same row, what could you use to link them together?
12 Why might someone choose to use Tinkercad Circuits instead of physical components when learning about electronics?
13 How do you add components like resistors or LEDs to your circuit in Tinkercad?
14 How do you test your circuit in Tinkercad to see if it’s working as expected?
Energy efficiency and energy labels 5
Energy efficiency
Energy efficiency is the relationship between useful energy (Eu ) that we get from a system and the energy supplied to it (Es ).
A device is energy efficient it if has high energy efficiency; that is, if the device uses most of the energy supplied, while minimising energy losses. Using energy-efficient electrical appliances allows saving energy and water, which contributes to a more efficient use of energy and natural resources.
Energy labels
Because saving energy and reducing carbon dioxide emissions is very important, the European Parliament requires all electrical appliances to have an energy label showing their level of energy efficiency. Therefore, it is mandatory.
The following aspects stand out:
• Brand and model. The name of the manufacturer and the model of the appliance.
• Energy efficiency of the product. It shows the energy consumption category of the appliance, compared to the average consumption of electrical appliances of the same type. The highest category is the lowest energy consumption, and vice versa.
• Annual electricity consumption (in kWh). Calculated based on standard conditions of use.
• Other characteristics. According to the type of appliance. For example, in a washing machine, litres of water used per wash, amount of clothes it can wash, and noise.
• QR Code. Included in devices with modern labels, it provides access to a description of the model in the European Union registry database.
UNDERSTANDING THE LABELS
Using an average class G refrigerator as a reference
Other characteristics of this type of appliance
Why is energy efficiency important for our planet?
Where can you find energy labels?
Calculating efficiency h = Eu ES
Remember
Energy efficiency can apply to buildings, not only to devices. If energy efficiency is taken into account when building a house, it is possible to considerably reduce energy consumption (for example, by placing the windows so that they maximise the amount of natural light or using insulating materials that reduce heating consumption). It is also possible to install solar panels, water purifiers and other means that make use of natural resources.
Vocabulary
Carbon dioxide, appliances, brand, resources.
15 Look up information about SDG targets 7.3, 11.6, 12.8 and 13.3 in anayaeducacion.es. Make a list of things you can do to help your country to reach those goals.
16 Find out the meaning of the following pictograms and say which type of electrical household appliances you could find them on:
The final challenge
Take action!
Unraveling Circuits
To achieve the challenge you must assemble a circuit, calculate the current and the equivalent resistance and finally, check your calculations using a multimeter to measure the resistance and the current.
STEP 1
Study the circuit
In a parallel circuit there is a 3 V battery connected to two 220 Ω and 1000 Ω resistors (the diagram is shown in the figure). We will calculate the current and voltage in all the circuit elements.
SCAN THIS CODE TO CONSULT THE GLOSSARY FOR THIS UNIT.
STEP 2
Elements and measurements
To assemble the circuit, you will need:
• A breadboard
• A 1 kΩ resistor and a 220 Ω resistor.
• A 3 V battery mounted using two AA 1.5 V batteries.
• A digital multimeter.
First measurement:
Equivalent resistance
It is important NOT to connect the batteries to the circuit. Copy the circuit shown in the image. Note that the multimeter is used to connect the parallel assembly of the two resistors. Change the selector to the correct scale in the sector with the Ω symbol and record the value.
Second measurement:
Total current in the circuit
Connect the battery to the same points where you connected the multimeter previously. To measure the electrical current, connect the multimeter in series. Prepare the assembly and note how the red wires are connected to the points of the circuit with the highest voltage. Change the selector to the correct scale in the sector with the A symbol and record the value.
STEP3
Check results and analyse errors
• To analyse the errors, we will use the absolute error (the difference between the value we calculated and the value we measured) and the relative error (the absolute error divided by the calculated value, multiplied times 100 to obtain a percentage).
• Copy this table entering the values you have measured and calculate the errors. Do you think the relative error percentages are low? Can the measurements be considered correct?
SECONDARY
Structures 4
1 Structures
Structure is any object that can be used to support loads
Design with solid elements joined to support forces, weights, and loads.
Nature is an inspiration in the design and construction of structures.
Natural structures: beaver homes, caves, etc.
Artificial structures: houses, bridges, etc.
It helps solving problems and improving structures.
1 Name five structures in nature that catch your attention due to their design and stability.
Forces
Forces are characterised by their value or intensity and their direction. They have effects on bodies (deforming them or changing their direction of motion).
Measuring tools scales, dynamometer measures in newtons (1 N = 1 kg • m/s2).
Static forces do not change over time.
Loads
Dynamic forces can change over time. Types are forces that affect a structure due to the weight it supports.
Accidental forces are produced by weather phenomena.
Centre of gravity geometrical point where the mass of an object is concentrated.
Types of loads Permanent
Depending on their duration and magnitude
Depending on how they are applied
2 Say what types of stresses or forces deform objects and give an example of each one.
Bending
Types of stress Stresses deform the objects on which they are applied.
Tension two forces that stretch an object.
Compression two forces that shorten an object.
Bending
Torsion
forces that bend or curve an object.
opposing forces that twist an object.
Shearing two opposing forces that cut an object.forces that twist an object.
Compression Torsion
Shearing
Structural components
Foundations
Types
Each element in a structure has a specific purpose.
Transmit structural loads to the ground
Curved frames that distribute the loads Arches
Steel cables that increase the strength of the structure Braces
Vertical elements that support compression stresses Pillars and columns
Horizontal elements that support the load between two support points Beams
3 Draw two types of structural elements and write their names.
Structural failures
Structural failures are inherent to human activity. To prevent them, preventive maintenance + careful and precise design.
Failure situations
Material fatigue
In structures subjected to loads structural material degrades
If the loads are in motion: + vibration of the material + degradation.
Rust and corrosion
Degradation or loss of material
Application of preventive substances (such as special paint) prevents it.
4 Lists the most common structural failures in a building.
Incorrect structural design
Selection of materials, location, arrangement, assembly etc. are essential for a correct and safe construction
Poor planning failures in the structure in time.
Types of structures
Mass structures
accumulation of natural materials, solid and resistant with high load bearing capacity.
combine resistant elements + horizontal beams e.g., pillars and columns.
Framed structures for covering and protecting.
Mass structures
Framed structures
Laminated structures
Hanging and suspended structures
Triangulated structures
Vaulted structures
based on braces and cables that support solid elements.
form more rigid and less deformable structures based on triangles (polygons that cannot be deformed, ideal for making resistant elements).
complex and expensive, but widely used to solve problems.
Arches
Vaults and domes
distribute loads among their parts.
5 Observe different bridge constructions and say what types of structures we use to make them.
Profiles
Laminated structures
Hanging and suspended structures
Triangulated structures
Arches
Vaults and domes
Profiles and trusses
are the commercial shapes in which steel, aluminium and other materials are generally supplied. They help support different stresses.
Triangular system for joining profiles and bars with a
6 Investigate what types of profiles are the most used in the construction of a house.
The lever
A lever is used to move heavy objects.
It is a bar that is placed on a support point also called fulcrum (f).
The force that must be applied to move the object is called power (P).
Resistance is the force that we overcome when moving it (R).
The distance of each force from the fulcrum is called the arm (B), so we will talk about the power arm (Bp) and the resistance arm (Br).
For a lever to be in balance, the product of each force and its arm must be equal.
7 Write an example of a lever of each type.
Transmit rotary motion.
Pulleys. Types: Gears
Multiplier
P
Power arm (BP) Resistance arm (BR)
There are three types of levers: Depending on the position of the fulcrum (f), the power (P) and the resistance (f), three types of levers can be distinguished:
Meaning that the product of the force (F) by the length of the inclined plane (d ) will be equal to the product of the resistance (R) by its height (h). P • BP = R • BR
Reducer + speed in driven wheel. - speed in driven wheel.
Type 1 f is between P and R
8 What are the differencies between a pulleys system and gears?
9 Fill the gaps: ‘The ... the angle of the plane, the ... the force required to move the object
Type 2 R is between P and f.
Type 3 P is between R and f.
Pulley and gears
Formula to calculate wheel speeds.
Data necessary for the calculation: diameters of the driving wheels (Dm) and the driven wheels (Dd) and the speed of the other wheel.
Vm Dm = Vd Dd
Data necessary for calculation: the number of teeth of the driven wheels (Zm) and directed (Zd), and the speed of the other gear, using the formula: Vm Zm = Vd Zd
The inclined plane
It is a surface that joins two points located at different heights, helping the raising or lowering of objects. The force (F) that must be applied to lift an object is always less than the resistance (R) F R d h F < R
• d = R • h
Electricity 5
An electric circuit and its components
Closed path made of a material that conducts electricity, in which some components are connected by wires through which electric charges can flow.
Components
Generators (voltage) Conductors (electric current) Loads (electrical resistors)
Control and protection elements
1 What is an electric circuit? Give the name of those parts essential for it to be an electric circuit.
The symbols allow understanding a circuit. Alternator:
Cells and batteries, alternators, and power supplies
Allow electricity to flow. This flow is prevented by using insulators
Light and heat emitters (conduction, convection and radiation), motion generators and others
Switches, push buttons (NO and NC) and multi-way switches
Electric magnitudes, units of measurement and formulas
Electric magnitudes are calculated with formulas and have their own units of measurement.
Magnitude
Unit of measurement
Formula
Voltage (V): amount of energy (E) supplied. Volt (V) Voltage = Energy ; V = E Charge Q
Current (I): number of charges that pass a point of the circuit in a unit of time. Amperes (A) Current = Charge ; I = Q Time t
Resistance (R): difficulty presented to flow of current. Ohms (Ω) Resistance = Volts ; R = V/I Current
Power: the amount of energy used in a period of time. Watts (W) Watts = Joules ; 1 W = 1 J / 1 s Second
Types of materials according to their R: conductor, insulator, semiconductor and superconductor.
law
The I that flows in an electric circuit is directly proportional to the V applied and inversely proportional to the R of the circuit.
2 What relationship is there between voltage, energy and electric charge?
Arrangement of the circuit
Set of loads
Two resistors connected in series.
Two resistors connected in parallel.
An unlimited number of loads can be connected.
Loads connected one after each other.
Three resistors connected in series.
n resistors connected in series.
3 There are four identical light bulbs in a circuit, two are connected in series and another two are connected in parallel. Which pair of bulbs will light up more?
4 In your notebook, draw a comparative table to show the characteristics of series and parallel circuits. Include their total resistance, current and voltage. Circuits
Loads connected to each other and to the voltage source.
Three resistors connected in parallel.
n resistors connected in parallel.
Properties of the electric circuit
Sources that do not run out when we use them.
Nuclear fusion (Sun)
Solar Wind
Wind + turbines
Heat (Earth)
Geothermal
Organic matter and transformed products
Biomass
Hydraulic
Water (kinetic energy)
Sources that run out when we use them.
Coal
Renewable
Electromagnetic radiation.
Electric energy. Sail boats, windmills, etc.
Electric energy. Heating systems.
Energy sources
Visible light. Infra-red radiation. Ultraviolet radiation.
Combustion = electricity and heat. Transformation = biodiesel.
Transformation in hydroelectric plants, tidal energy plants and wave energy plants.
Non-renewable
Fossil fuel (plant matter)
Petroleum
Marine origin
Industrial use. Manufacture of steel.
In addition to generating electric energy, they are used for:
Transportation (fuels), plastic, asphalt.
Natural gas
Fossil origin Not very polluting
Heating and cooking.
Nuclear energy
Fission of uranium-235 atoms
Nuclear weapons (destructive purpose).
5 Make a table listing the advantages and disadvantages of using renewable energy sources. Draw two columns, with the advantages in the right column, and the disadvantages in the left column.
Protoboard and Tinkercad circuits
Protoboard
The rows are connected horizontally
Columns are connected vertically
They help us to simplify the assembly of circuits
Tinkercad circuits
Components
Measuring instruments
Energy efficiency
Enables the simulation of electrical and electronic circuits
Direct
Via prototyping board Includes Connection
6 Make a list of the Tinkercad Circuits components you are familiar with.
Energy efficiency
Maximum use + minimal losses
Energy labelling
• Required by European Parliament (home appliances) energy savings + lower CO2 emissions.
• Identifies the energy efficiency level.
Energy label fields
Brand and model
Energy efficiency class (A – G)
Annual electricity consumption (kWh)
QR Code
Consumption compared to the average of the same type of device. (+ category, - consumption)
Calculated in standard conditions.
Other characteristics
Description of the model (European Union database)
7 Make a list of the most important information that an energy efficiency label must have.
Brand and model
Energy efficiency of the product
Electrical consumption (annual or in 100 cycles)
Other characteristics of this type of appliance
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