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The final part of a quick guide to the basics of Python aimed at Key Stage 3 students. Learn about importing turtle to command a moving object. Python - #6 - Turtle Import the Turtle The turtle library stores all of the code to create and move an object called a turtle . The turtle library must be imported into your Python program before you can use it to draw lines, shapes and colours . Create a new Python program and save the file as PythonTurtle . Write import turtle as the first line of code. Basic Shapes The turtle can be controlled by writing how many pixels it should travel forward and the angle it should point left or right . Moving Forwards turtle.forward(100) will move the turtle forward by 100 pixels. turtle.forward(200) will move the turtle forward by 200 pixels. When using the left command or the right command, the turtle won't actually move , but it will rotate by the number of degrees that you state. For example, typing turtle.left(90) will point the turtle upwards . Rotating Left & Right Copy the code to the right to make the turtle draw a square. Then try to make: A Rectangle A Triangle A Pentagon A Hexagon Square Rectangle Triangle Pentagon Hexagon Hint: To work out the angles, divide 360 by the number of sides. Using Loops You can use a for loop to repeat code . This is especially helpfully with intricate shapes with many sides. The code below will print a square but in only 3 lines instead of the 8 lines from task 2. This is the number of times the code underneath will be repeated . Change it to a higher number to repeat it more often . Each line after the 'for num in range' line must be indented . Press the tab key once on your keyboard to indent your code. Task 3 - Copy the code above to make the turtle draw a square using a loop. Then try to make: A Heptagon An Octagon A Circle A Pentagram (5-sided Star) Square Heptagon Octagon Circle Pentagram Hint: To work out the angles, divide 360 by the number of sides. Advanced Features Choose a background colour turtle .bgcolor("red") Choose the line size and colour turtle.pensize(6) turtle.color("green") Fill a shape turtle.color("yellow") turtle.begin_fill() (put your turtle's directions in here) turtle.end_fill() Lift the pen turtle.penup() turtle.pendown() Speed up/Slow down the turtle turtle.speed(speed=10) Change the turtle's appearance turtle.shape("turtle") Other options include "circle" and "arrow". Task 4 - Use the code above to make: A blue square on a red background. A yellow triangle on a pink background. Two different coloured circles - not touching each other. Three different shapes of three different colours - not touching each other. Complex Shapes Use everything that you have learned on this page to help you create more complex shapes. You could try: A Flower A Word (like your name - you will need to use the penup() and pendown() commands. A Christmas tree A Landscape (green ground, blue sky, yellow sun) <<< Selection

Learn about computational methods including problem recognition, decomposition, divide and conquer, abstraction, backtracking, data mining, heuristics, performance modelling, pipelining and visualisation. Based on the OCR H446 Computer Science A-Level specification. Exam Board: OCR A-Level Specification: Computer Science H446 2.2 - Computational Methods Watch on YouTube : Problem recognition Decomposition Divide and conquer Abstraction Backtracking Data mining Heuristics Performance modelling Pipelining Visualisation Computational methods are techniques to analyse problems and design efficient , effective solutions . Problem Recognition Problem recognition is the process of identifying that a problem exists and understanding its nature before attempting to solve it. It involves determining the aims of the task , identifying constraints and requirements , and clarifying what inputs , outputs and processes are expected from the solution . Effective problem recognition ensures the developer understands the real-world context and avoids solving the wrong problem or missing key details . It is the essential first step that guides all later stages of computational thinking and system design . YouTube video uploading soon Decomposition Decomposition involves breaking a complex system or task into smaller , more manageable components that are easier to design , implement and test . Each sub-problem should ideally be independent and solve a specific part of the overall task , which helps reduce complexity and supports modular program design . This approach enables different developers to work on different components simultaneously and simplifies debugging , maintenance and future updates . By working through smaller logical parts , the full problem becomes far more approachable and structured . YouTube video uploading soon Divide and Conquer Divide and conquer is a technique that splits a problem into smaller sub-problems of the same type , solves them (often using recursion ), and then combines the solutions to produce the final answer . This approach can significantly improve efficiency by reducing large input sizes into more manageable chunks , as seen in algorithms like quicksort . Divide and conquer algorithms include a binary search and a merge sort . The time complexity of divide and conquer algorithms is logarithmic - O(log n) - allowing complex problems to be solved much quicker than other algorithms . YouTube video uploading soon Abstraction Abstraction means removing unnecessary details to focus only on the most important features of a problem or system . It allows programmers to create simplified models that capture essential behaviour without becoming overwhelmed by irrelevant complexities . Abstraction enables generalisation , reusable designs and clearer reasoning about how components interact . In computational contexts, abstraction also highlights the difference between real-world systems and their simplified computational models . YouTube video uploading soon Backtracking Backtracking is used to explore possible solutions to a problem by building a partial solution and abandoning it as soon as it becomes clear it cannot succeed . It works by trying an option , checking whether it leads towards a valid solution , and backtracking to try a different path if a dead end is reached . This approach is used in constraint-based problems such as maze solving . While powerful , backtracking can be computationally expensive , so it often benefits from heuristics or pruning strategies . YouTube video uploading soon Data Mining Data mining is the process of extracting useful patterns , trends and relationships from large datasets . It enables organisations to identify hidden insights , predict behaviours and support data-driven decision-making , particularly in fields such as marketing , healthcare , finance and security . Data mining can lead to enhanced decision-making that can result in innovation , a competitive advantage against similar organisations and increased revenue . It can be used to identify anomalies or unused features . However, data mining doesn't explain the patterns it can identify and it requires powerful computers with a lot of processing power to handle huge amounts of data . YouTube video uploading soon Heuristics Heuristics are approximate problem-solving strategies that aim to produce good solutions quickly when exact , optimal methods are too slow or computationally impractical . They rely on rules of thumb to guide searches through very large solution spaces efficiently . Heuristics are widely used in artificial intelligence , optimisation tasks and complex search algorithms such as A* , where perfect accuracy is less important than fast , practical solutions . The trade-off is that heuristic methods are not guaranteed to produce the optimal answer , but they dramatically reduce processing time . YouTube video uploading soon Performance Modelling Performance modelling is the process of predicting how a system or algorithm will behave under different workloads , input sizes or hardware environments . It uses tools such as mathematical analysis , simulation and Big O notation to estimate required resources such as processing time or memory use . Performance modelling offers a cheaper , quicker and often safer way to test applications . For example, when a company beta tests an online game , it can trial the system with a smaller group of players and then apply performance modelling to predict how much server capacity will be needed when the game is fully released . YouTube video uploading soon Pipelining Pipelining is a technique in which different stages of a process are overlapped so that multiple instructions or operations are being processed simultaneously at different stages . In CPU architecture , for example, one instruction might be fetched while another is decoded and a third is executed , increasing overall throughput without increasing clock speed . Pipelining can also be used in algorithms or data-processing systems to prevent idle time in stages that operate independently . However, pipelining introduces complexity because dependencies or branch mispredictions may require a pipeline to be flushed - interrupting flow and reducing efficiency . YouTube video uploading soon Visualisation Visualisation supports the understanding of a problem by presenting information in a clearer and more accessible form than text alone . It is useful for explaining complex ideas or identifying patterns . Data can be shown visually through diagrams , graphs , trees , flowcharts or tables . The advantages of visualisation include helping to model , represent , analyse or summarise complex concepts . It allows information to be communicated more clearly and in a way that is easier to interpret . It can also provide different perspectives on how a problem might be solved . YouTube video uploading soon This page is under active development. Check here for the latest progress update. Q uesto's K ey T erms Computational Methods: problem recognition, decomposition, divide and conquer, abstraction, backtracking, data mining, heuristics, performance modelling, pipelining, visualisation D id Y ou K now? Real-time location services like Google Maps use heuristics to guess travel times using heuristics such as estimated speeds , traffic history and shortcuts to make fast but approximate route suggestions . 2.1 - Programming Techniques A-Level Topics 3.1a-d - Algorithm Complexity

Learn how to create and use dictionaries in Python. Try practice tasks and learn through text and images. Perfect for students learning GCSE Computer Science in UK schools. top Python 8C - Dictionaries Creating a Dictionary Dictionaries are used in Python to link items of data together . The example on this page uses a footballer dictionary which links a player with a team they played for. To define a dictionary, use curly brackets { } and separate linked data with a colon . A dictionary can be written on one line but the method below makes it easier to read: Printing Data from a Dictionary The first part of the linked data in a dictionary is called the key (e.g. each footballer in my example above). The second part of the linked data in a dictionary is called the value (e.g. each team). Example: key : value "Harry Kane" : "Tottenham Hotspur" A for loop can be used to cycle through each set of keys and values in the dictionary: Practice Task 1 a) Create a dictionary of your teachers and the subject they teach. b) Print their name and the subject they teach on each line. Example solution: Adding and Removing Data from a Dictionary Data can be added to a dictionary by stating the new key and value . You must use square brackets - [ ] The new data will be added to the end of the dictionary. You can print the whole dictionary to see any changes - e.g. print(playerdictionary) Data can be removed from a dictionary by stating the new key to remove in a pop command. You can print the whole dictionary to see any changes - e.g. print(playerdictionary) The whole dictionary can be cleared (reset to blank) using the clear command. Practice Task 2 a) Ask the user to enter a new teacher and their subject. b) Ask the user to remove a teacher. c) Print the list of teachers and check the new teacher has been added and the other one removed. Example solution: Searching Through a Dictionary An if statement can be used to check if a specific key is in a dictionary. If the key is in the dictionary then a message can be displayed using the key and the value . Otherwise, an else statement can output an appropriate response. To search for a value in a dictionary a for loop should be used to cycle through each key . If the value of each key matches the value that is being searched for then it will be printed. Practice Task 3 a) Create a search that allows a user to enter a teacher's name and prints the subject that they teach. b) Include an else statement to print a response if a teacher is not in the dictionary. Example solution: Changing Data & Copying a Dictionary The way to change values is similar to adding new data. The first input below is to determine the key and the second input determines the new value to be changed to. The copy command is used to make a duplicate of a dictionary . Practice Task 4 a) Create a copy of your teacher dictionary. b) Allow the user to enter a teacher and a new subject that they teach. c) Print the copy of the dictionary with the new values. Example solution: Using a Dictionary to Make a Game The code below is used to make a puzzle game where the user has to type in a footballer and the team they played for. I have added comments to explain the different parts of the code. A separate list has been created at the start to store the names of keys (players) that been correctly guessed . A while loop is used to constantly ask the user for players and teams. When they have guessed all 10 players (and the correct list reaches 10 ) the loop breaks and the game end. Instead of a further practice task here, Task 6 of the Section 8 Practice tasks page challenges you to make a similar game using a dictionary. ⬅ 8b - 2D Lists Section 8 Practice Tasks ➡

Learn how to create your own web page in HTML. The guide features 10 easy to follow steps from setting up the basic tags to adding images, videos and more pages. When you see the checklist icon, complete the task in order to make your own HTML web page. HTML Guide 1. Setting up the web page 2. Essential tags 3. Text tags 4. Hyperlinks 5. Images 6. Organisation tags 7. Head tags 8. Videos 9. Colours & Fonts 10. More pages Watch on YouTube: These steps will show you how to make a HTML fanpage so get thinking of an appropriate topic - maybe your favourite book, movie or sports team? Download Notepad++ at home

Learn about the four network topology types - bus, ring, star and mesh - plus advantages and disadvantages of each. Based on the 2020 Eduqas (WJEC) GCSE specification. 3.3: Network Topology Exam Board: Eduqas / WJEC Specification: 2020 + What is a network topology? Network topology refers to layout of computer systems on a network . Devices in a network topology diagram are often called 'nodes' . What are the different types of network topology? Bus Topology The nodes are connected to a bus (a central cable along which all data is transferred across the network). How it works: Data packets are sent along the main cable (sometimes known as the 'backbone') from the source computer to each other system in turn . Each system checks the destination address of the data packets. If the addresses match then the data is accepted otherwise it is passed on to the next system. Terminators are required at both ends of the bus to mark the end of the cable. Advantages: Because of the simple layout, it is easy to attach another system to the main cable without disrupting the whole network . A bus topology is quick to set up once the main cable has been established making it optimal for temporary networks . A bus topology is cost-effective because it usually contains less cabling than other topologies and requires no additional hardware (like a hub or switch). Disadvantages: Poor security as data packets are passed on to each system on the network. Data collisions are likely - this is when two systems attempt to transfer data on the same line at the exact same time. Resending the data wastes time and slows down the network . The main cable will only have a limited length which can become crowded and slows the network speed as more systems are attached. The main cable must also be terminated properly . Ring Topology Computer systems are connected together in a single loop . How it works: Packets are transferred around the ring in one direction , passing from one computer system to the next in a loop . As the packets arrive at each computer system, the computer checks the destination address contained in the data packet to see if it matches its own address. If the addresses match the computer accepts and processes the data packet, otherwise it passes it on to the next system. Advantages: Data collisions are avoided as data packets are transmitted in one direction around the ring. Attaching more systems to a ring topology won't affect the transfer speed (bandwidth ) as much as other layouts like a bus topology because the data is transferred at a consistent speed . Disadvantages: If any system on the network fails then the whole network fails as the loop is broken and data can't be transferred to all systems. To add a new system to a ring topology the network must be temporarily shut down . Star Topology Each computer system is connected to a central device , usually a hub or switch . How it works: Each computer system is connected to the central hub or switch and transfers its data packets there. The hub or switch looks at the destination address and transfers the packets directly to the intended computer. Advantages: A star topology has improved security because data packets are sent directly to and from the hub / switch in the centre and not necessarily all devices like in a bus or ring topology. New systems can be attached directly to the central system so the network doesn't need to be shut down . System failures of attached computers won't usually cause complete network failure. Transfer speeds are generally fast in a star topology as there are minimal network collisions . Disadvantages: Extra hardware (the hub or switch) is required to be purchased, installed and maintained. If the central system (the hub or switch) fails then the whole network will be unusable until the error is fixed. Mesh Topology In a full mesh network, each computer system is connected to every other computer system . There is also a partial mesh network where only some nodes (e.g. a printer) are connected to every other node. How it works: Data packets are transferred to the destination address along the quickest path , travelling from node to node. If a pathway is broken , there are many alternative paths that the packets can take. Advantages: If one cable or system fails then data packets can take an alternative route and still reach the destination address. Because of the large possible number of systems and connections, a mesh topology can usually withstand large amounts of data traffic . New systems can be added to the network without disrupting the entire topology . Disadvantages: Because of the possibly large amount of cables required (especially in a full mesh topology) this network layout can be expensive to install and maintain . Redundant cabling should be avoided - this is when cables are connected between systems that won't ever need to communicate . Q uesto's Q uestions 3.3 - Network Topology: 1. Draw and label diagrams of all four topologies . [12 ] 2a. A school currently uses a bus topology but is considering changing to a ring topology . Describe two advantages and two disadvantages of both topologies. [ 8 ] 2b. An office currently uses a star topology but is considering changing to a mesh topology . Describe two advantages and two disadvantages of both topologies. [ 8 ] 3.2 - Data Packets & Switching Theory Topics 3.4 - Network Hardware & Routing

Learn about the purpose and characteristics of intranets, the internet and extranets - all three types of World Wide Web technologies. Based on the 2016 OCR Cambridge Technicals Level 3 IT specification for Unit 2 (Global Information). 1.5 - WWW Technologies Exam Board: OCR Specification: 2016 - Unit 2 The internet is a global network of interconnected networks . The world wide web (WWW ) is not the same as the internet. It is a way of accessing information , using protocols such as HTTPS to view web pages . There are three types of world wide web technologies : Internet Intranet Extranet The internet i s a global network of interconnected networks . The internet is public and users have open access . Examples of use: Accessing web pages to shop and watch videos . Businesses may use web pages to advertise their products and allow customers to purchase items. An intranet is a private network that is only accessible to authorised users (e.g. members of a business or school). Intranets are private and users have closed access . Examples of use: Because an intranet is a secured online area , schools often use an intranet to log in to that displays information for teachers and students (such as test results or upcoming events ). Businesses might use an intranet for employees to see sales and performance data or for communication because it can be accessed remotely . An extranet is a private network that is accessible using the internet but provides access only to authorised users . Extranets are private and users have shared access . Example of use: Hotel booking companies (like booking.com) use an extranet to allow hotel owners to log in via the internet to access and update their information. Network Characteristics When connecting to WWW technologies there are several characteristics that a user must consider: Speed Speed refers to how quickly data can be accessed . For example, an extranet is the slowest network to use because it must be accessed through the internet first. Security Security relates to how likely the data will be kept secure . An intranet is more secure than the internet because only authorised users can log in. Access Levels Access levels , or permissions , refers to who can see what, in terms of data and files . Resources on an intranet can be set so that only certain users can view them. Accessibility This characteristic relates to how available the data is . For example, the internet can be accessed on any network-enabled device, at any time . Q uesto's Q uestions 1.5 - WWW Technologies: 1. Explain the difference between the internet and the world wide web . [2 ] 2. Describe each of the 3 types of WWW technology . You must mention whether they are private or public and what type of access they have. a. Internet b. Intranet c. Extranet [2 each ] 3. Describe at least one example of how each of the 3 types of WWW technology could be used . [6 ] 4. Describe the 3 WWW technologies in terms of each of the 4 network characteristics . You need to think carefully about this; the descriptions under each icon above can help you with certain answers. To start, describe the speed, security, access levels and accessibility of an intranet . [12 each ] 1.4 - Internet Connections Topic List 1.6 - Information Formats

Learn about how information can be classified into groups including private, public, sensitive and confidential. Based on the 2016 OCR Cambridge Technicals Level 3 IT specification for Unit 2 (Global Information). 2.2 - Information Classification Exam Board: OCR Specification: 2016 - Unit 2 Information can be classified into different groups . Some data may fall into more than one classification. Sensitive Information Description: Information that should be protected from being publicly released as it could harm the safety or privacy of an organisation or an individual . Examples: Medical data that could be embarrassing to an individual if released. Financial data that will negatively impact the company if made public to competitors. Non-Sensitive Information Description: Information that can be released publicly with no fear of negative consequence . Examples: Store information including shop addresses , opening hours and the names of senior managers. Product information including prices , online reviews and general availability . Private Information Description: Private information relates to an individual and it should not be shared with anyone else without the data subject's permission . Private information is protected by the Data Protection Act and would need to be stored securely so it cannot be accessed without authorisation. Examples: Home addresses, contact information, birth dates and banking details . Employee data such as linked bank accounts and addresses. Public Information Description: Released to the public and can therefore be seen by anyone . Public information is non-sensitive . Examples: Social media usernames, posts and shared images. Public business information including addresses, promotional material and opening times. A government report like the national census every ten years. Personal Information Description: Identifiable data about a specific individual . Examples: Full name , date of birth , gender , marital status, medical history, sexual orientation and voting history. Business Information Description: Any kind of data about a specific business. This information could be public or private. Examples: Address of its headquarters Financial data or employee details. Annual sales figures . Confidential Information Description: Private data that is more restricted than sensitive information , with access limited to only those who need to know. Examples: Doctor / therapist notes Business Profits and losses Trade secrets Classified Information Description: Highly sensitive information stored by a government institution , requiring the highest levels of restricted access . Access is usually restricted by law and only viewable by authorised individuals or groups. In the UK there are three levels of classified information: OFFICIAL , SECRET and TOP SECRET . Examples: Military data Terrorism precautions Crime scene reports Anonymised Information Description: Anonymisation removes personally identifiable data from information so that an individual cannot be identified . This allows the information to be used in much wider context without running the risk of legal action. Examples: Partially anonymised information - where some of the personal information has been removed and replaced by a symbol . Completely anonymised information - where all identifiable data has been removed . Bank details are often partially or completely anonymised. A partially anonymised credit card number might be listed as: **** - **** - **** - 7427 Problems with anonymising data include: If sensitive data is not anonymised enough and the person can be identified . Useful information could be lost if too much data is anonymised . The public could lose trust in an organisation if data is insufficiently anonymised . Q uesto's Q uestions 2.2 - Information Classification: 1. Describe each type of information classification and give at least two examples : a. Sensitive information [3 ] b. Non-Sensitive information [3 ] c. Private information [3 ] d. Public information [3 ] e. Business information [3 ] f. Confidential information [3 ] g. Classified information [3 ] h. Anonymised information (partial and complete) [6 ] 2. State which classification(s) the following pieces of information would be categorised as. It might fit into more than one category. a. Shop opening times [1 ] b. Medical history [1 ] c. Twitter username [1 ] d. Crime scene report [1 ] 3. Describe three problems that organisations should consider when anonymising data . [6 ] 2.1 - Information Styles 2.3 - Quality of Information Topic List

Learn about algorithms for data structures such as stacks, queues, linked lists and trees, as well as how to traverse trees with depth-first and breadth-first traversal methods. Based on the OCR H446 Computer Science A-Level specification. Exam Board: OCR A-Level Specification: Computer Science H446 3.1e - Data Structure Algorithms Watch on YouTube : Stacks Queues Linked Lists Trees Tree traversal Being able to read , trace and write code for data structure algorithms (stacks , queues , linked lists and trees ) is vital. Stacks A stack stores data in a last in , first out (LIFO ) order, meaning the most recently added item is the first one to be removed . It works much like a stack of plates - you can only add or remove from the top . Two integral functions are push and pop . The push operation adds (or “pushes”) a new item onto the top of the stack . The pop operation removes (or “pops”) the item from the top of the stack . Stacks are commonly used in undo features , function calls and expression evaluation , where tracking the most recent item first is important . YouTube video uploading soon Queues A queue stores items in a first in , first out (FIFO ) order, meaning the first item added is the first one removed . New items are added at the rear of the queue using an enqueue operation, and items are removed from the front using a dequeue operation. Queues are often used in task scheduling , print spooling and data buffering , where operations must occur in the same order they were requested . YouTube video uploading soon Linked Lists A linked list is a dynamic data structure made up of a series of elements called nodes , where each node contains data and a pointer to the next node in the sequence . Unlike arrays, linked lists do not store elements in contiguous memory locations , making it easy to insert or delete items without having to shift other elements . The head is the first node in the list , and the last node usually points to null , indicating the end of the list . YouTube video uploading soon Trees A tree is a hierarchical data structure made up of nodes connected by branches , starting from a single root node . Each node can have child nodes , and nodes without children are called leaf nodes . Trees are useful for representing data with natural hierarchies , such as file systems or organisational charts . A binary search tree is a special type of tree where each node has at most two children - a left and a right . All values in the left subtree are smaller than the parent node , and all values in the right subtree are larger . This structure allows for efficient searching , insertion and deletion of data , often much faster than in lists or arrays . YouTube video uploading soon Tree Traversal 'Tree traversal ' refers to the method used to visit every node in a tree data structure in a specific , organised order . Depth-first (also called post-order ) traversal explores a tree by moving as far down one branch as possible before backtracking , visiting nodes in a deep , top-to-bottom manner . It uses a stack to keep track of nodes still to explore , pushing new branches onto the stack and popping them when backtracking . Breadth-first traversal explores the tree level by level , visiting all nodes on one level before moving down to the next . It uses a queue to hold nodes in the order they should be visited , ensuring the traversal expands outward evenly from the root . YouTube video uploading soon This page is under active development. Check here for the latest progress update. Q uesto's K ey T erms Stacks and Queues: stack, queue, last in first out (LIFO), first in first out (FIFO), push, pop, enqueue, dequeue, pointer Linked Lists: linked list, null Trees: tree, binary tree, binary search tree, root node, branch, depth-first traversal, breadth-first traversal D id Y ou K now? Spotify playlists work like linked lists because each song links to the next , allowing tracks to be added , removed or reordered instantly without reshuffling the whole playlist. This makes the app fast and efficient even when handling huge playlists with thousands of songs . 3.1a-d - Algorithm Complexity A-Level Topics 3.1f - Standard Algorithms

Navigate between all Unit F160 (Fundamentals of Application Development) topics in the OCR Cambridge Advanced National in Computing (AAQ) specification. Qualification: Cambridge Advanced National in Computing (AAQ) Unit: F160: Fundamentals of Application Development Certificate: Computing: Application Development (H029 / H129) Unit F160: Fundamentals of Application Development These pages are based on content from the OCR Cambridge Advanced National in Computing (AAQ) specification . Unit F160 YouTube Playlist Topic 1: Types of Software 1.1 - Programs and Applications 1.2 - Operating Systems 1.3.1 - Application Types 1.3.2 - Application Software Categories 1.3.3 - Application Software Types Topic 2: Software Development Models 2.1 - Software Development Models 2.2 - Development Phases Topic 3: Planning Development Projects 3.1 - Planning Projects 3.2 - Project Planning Tools Topic 4: Application Design Scoping 4.1 - Gathering Client Requirements 4.2 - Client Requirement Specifications 4.3 - Decomposition Methods Topic 5: Human-Computer Interface 5.1.1 - Types of Human-Computer Interaction (HCI) 5.1.2 - Types of Devices 5.2 - HCI Visual Design Considerations 5.3 - HCI Design Documents & Diagrams Topic 6: Job Roles & Skills 6.1 - Job Roles 6.2 - Communication Skills

Learn about the benefits of compression and the differences between lossy and lossless compression. Also, learn how compression ratios work. Based on the 2020 Eduqas (WJEC) GCSE specification. 4.8: Compression Exam Board: Eduqas / WJEC Specification: 2020 + What is compression? To compress a file means to make its size smaller . Benefits of compression include: Files take up less storage space (so more files can be stored). Files can be transferred quicker (because they are smaller). Files can be read from or written to quicker . There are two methods that are used to compress files: Lossy and Lossless . Lossy Compression Lossy compression uses an algorithm (set of instructions) to analyse a file and remove data that cannot be heard or seen by humans . For example, a lossy algorithm would analyse the sound waves of an audio file and remove any frequencies which humans cannot hear. This process reduces the size of the file . Further lossy compression will remove data that humans can see / hear . For example, the dog image to the right has been strongly compressed using a lossy algorithm and some data has clearly been removed. Lossy compression removes the data permanently , so the file can never return to its original form . Lossy compression is often used with images , audio and video to reduce the file size, for example to send over the internet. Lossless Compression Lossless compression reduces the size of a file without permanently removing any data . Because of this, the file is returned to its original form when decompressed, so no quality is lost . A file that is compressed with a lossless algorithm is usually larger than a file compressed with a lossy algorithm because no data has been permanently removed. Lossless compression is used with files that would not work if data was removed, for example executable files (e.g. programs and games) or word documents . Remember that lossy and lossless compression do not just refer to images. Below is an audio file that has been compressed with lossy compression . Data has been removed so the audio quality has decreased. 197 KB 81 KB 43 KB Compression Ratios Original File Size Compression Ratio = Compressed File Size 4 Mb = 5:1 20 Mb Example: A file has been compressed from 20 megabytes down to 4 megabytes. This is a compression ratio of 5:1. To calculate the size after compression , divide the original size by the first ratio value, then multiply it by the second value. For example, the new size for file 1 is (210 ÷ 10) x 3 = 63 MB. Triple-click the final column to see the right answers. Q uesto's Q uestions 4.8 - Compression: 1. Describe 3 benefits of compressing a file . [ 3 ] 2. Describe the differences between lossy and lossless compression . [4 ] 3. A student needs to compress a Microsoft Word document to send in an email. Suggest which type of compression they should use and why . [ 2 ] 4a. A text file was 72 KB and was compressed to 8 KB . State the compression ratio . 4b. An audio file was 4.5 MB and has been compressed to 0.9 MB. State the ratio. 4c. A 20 MB file is compressed with a ratio of 5:2 . What is the size of the compressed file ? [ 1 each ] 63MB 164KB 96KB 4.7 Sound Representation Theory Topics 5.1 - Data Structures

Test your ability to create a more complex program in Python based on a given scenario. Perfect for students learning GCSE Computer Science in UK schools. Extended Task 3 Hi, Susanna here, I want to make a blackjack-like program that I can play for fun at home in between revising for Computer Science. The aim of my blackjack game is to get as close to 21 as possible with the most number of cards, without going over. So... The user can choose whether to be hit with a new card (a number between 1 and 8) or fold and stop. Each number they are dealt adds up to their total . If the total goes over 21, then they lose . If they bust (when over 21) or folded then their final number and their number of cards is displayed . Blackjack For this task, you will need to create a document and include the following sections (with screenshots where appropriate): An introduction to explain the Purpose of your program . A List of Requirements for a successful program. Screenshots of your code (with comments in your code to show understanding). Testing – Create a plan to show how you will test your program and then explanations of any errors that you found and how they were fixed . An Evaluation of what worked, what didn’t, and how you met each of your requirements from your original list. Also, discuss further improvements that you could have made to improve your program. Example solution: Helpful reminders for this task: Think about the type of loop that you need. Will you need more than one loop? What variables will you need? Remember to use an input . What will you ask the user? How will you use their response? Remember to use ‘import random’ and randint to create a random number . What outputs do you need and when? What should you display… After each hand? At the beginning? At the end? ⬅ Extended Task 2 (Lottery) Extended Task 4 (Vet Surgery) ➡

Learn how to set up a brand new HTML page using Notepad ++. Find out how to format the document ready for tags to be entered. 1. Setting up a HTML document HTML Guide Watch on YouTube: This guide assumes that you have Notepad++ already installed. If you are working at home and need to download Notepad++ then click here . Save as .html file Notepad++ assumes you are writing a text file so you must change the file type . Open Notepad++ Click File then Save As... Change Save as type: from Normal text file (.txt) to Hyper Text Markup Language file (.html) Change File name: to Fanpage Website.html These steps are necessary to set up your HTML web page correctly. Open Notepad ++ and save your file as a .html document. Editor vs. Browser View In newer versions of Notepad++ click on View then View Current File in and choose a browser installed on your computer such as Chrome . Some versions of Notepad++ enable you to view the document in a web browser by selecting Run then an option such as Launch in Chrome . It is good practice to have both Notepad++ and a web browser open at the same time so that you can easily check if any changes have been made correctly. Remember to press the save icon ( ) before you refresh your browser . Don't expect your web browser to show anything yet. Next it is time to add our essential tags for the structure of the web page. HTML Guide 2. Essential Tags