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A complete list of tags required for students to know how to use in the 2016 Eduqas GCSE specification. Follow the links on each tag to see how to use them. Here you can find a list of tags. Click a tag to see how to use it. Tags for Eduqas GCSE:

Learn about the elements of a data flow diagram and factors that may disrupt them. Based on the 2016 OCR Cambridge Technicals Level 3 IT specification for Unit 2 (Global Information). 5.2 - Data Flow Diagrams Exam Board: OCR Specification: 2016 - Unit 2 A data flow diagram is a visual representation of how data is transferred within a system or organisation . Data flow diagrams are often abbreviated to just 'DFD '. You will need to recognise the symbols , understand the diagrams and explain how data flow can be affected . Data Flow Diagram Symbols The common symbols used in a DFD are shown below: External Entity (e.g. Employee, Customer) Alternative DFD symbols you may see on the exam paper (both sets of symbols have been accepted in previous exam papers): Process (e.g. Calculate Pay, Review Application) Data Store (e.g. Staff Database, Customer Database) External Entity Process Data Store Data Flow Level 0 data flow diagrams show the transfer of data in a simple manner . Processes may be generalised and not shown separately , for a more basic overview . Below is an example of a Level 0 DFD to show the process of an employee submitting an application to be promoted : Level 1 data flow diagrams show the transfer of data in a more detailed manner . Processes are shown separately , for a more complex and realistic overview . Below is an example of a Level 1 DFD to show the process of an employee submitting an application to be promoted . The individual processes have been expanded from the Level 0 DFD above to show how the application must first be signed off by an administrator before it is reviewed by management: Rules for Drawing a Level 1 DFD Data flows only in one direction . Every data flow is labelled (with the data itself , not the action). Every data flow connects to at least one process . At least one input or output for each external entity . Impacts Affecting the Flow of Information There are several reasons why the flow of information within an organisation may be delayed or inefficient , such as: Information characteristics e.g. information is entered incorrectly, causing delays. Human error e.g. information is lost or staff don't follow protocol. Hardware failure e.g. network connection breaking or system failure. Communication breakdown e.g. meetings postponed or emails unread. Q uesto's Q uestions 5.2 - Data Flow Diagrams: 1. Draw the symbols for the four parts of a data flow diagram . [4 ] 2. Look at the image of the Level 1 DFD . State one example of: An external entity A process A data flow A data store [1 each ] 3. Give one difference between a Level 0 and Level 1 DFD . [2 ] 4. State three rules for drawing a correct data flow diagram . [3 ] 5. After heavy snow, a school has decided to shut for the next two days. Many parents were not informed of this decision and are angry that they brought their children in. Give three reasons why the transfer of data (the data being a message about school closure) might not have flowed efficiently in this example. [6 ] 1 Level 0 Data Flow Diagram Level 1 Data Flow Diagram 5.1 - Data Types & Sources Topic List 6.1 - Security Principles

Learn about the three main types of memory in a computer system - RAM (Random Access Memory), ROM (Read Only Memory) and Cache Memory. Memory What is memory? Memory is where a computer stores information , instructions and data so it can use them quickly when needed . There are three main types of memory : RAM Random Access Memory ROM Read Only Memory Cache Memory What is Random Access Memory? RAM is volatile (this means that when power is lost, the data is deleted ). Every program that is being run by the computer (such as Google Chrome, Spotify or Microsoft Word) is stored in RAM . RAM is made up of a large number of storage locations , and each is identified with a unique address . What is Read Only Memory? ROM is non-volatile (this means that data is saved, even when the power is off ). The start-up instructions (for when a computer is switched on ) are stored in ROM . ROM is read-only, which means that it cannot be edited or changed . What is Cache Memory? Cache memory is fast to access because it is built into the CPU (or very close to it) . Cache memory stores data that needs to be accessed very frequently . Cache memory is very expensive , so there is only a small amount in most computers. How can a computer run faster? There are many reasons why a computer may be running slowly . Here are some methods related to memory that can help speed up a system : Close unnecessary programs to free up RAM so it doesn't run out of memory space . Add more RAM so the computer can run more programs at once without slowing down . Increase the cache size so the CPU can access important data more quickly . KS3 Home Note: Only larger systems like desktop computers can have their components easily upgraded and replaced.

Navigate between all Unit 2 (Global Information) topics in the OCR Cambridge Technicals Level 3 IT 2016 specification. OCR Cambridge Technicals IT Level 3 Unit 2: Global Information These pages are based on content from the OCR Cambridge Technicals 2016 Level 3 IT specification . This website is in no way affiliated with OCR . This qualification stopped in July 2025. The pages on the site will remain for at least two years. LO1 (Devices & The Internet ) 1.1 - Holders of Information 1.2 - Storage Media 1.3 - Access & Storage Devices 1.4 - Internet Connections 1.5 - WWW Technologies 1.6 - Information Formats 1.7 & 1.8 - Internet Pros & Cons LO2 (Information Styles & Quality ) 2.1 - Information Styles 2.2 - Information Classification 2.3 - Quality of Information 2.4 - Information Management LO3 (Categories & Analysis ) 3.1 - Data vs. Information 3.2 & 3.3 - Information Categories 3.4 - Stages of Data Analysis 3.5 - Data Analysis Tools 3.6 - Information Systems LO4 (Legislation ) 4.1 - UK Legislation 4.2 - Global Legislation 4.3 - Green IT LO5 (Flow of Information ) 5.1 - Data Types & Sources 5.2 - Data Flow Diagrams LO6 (Security & Protection ) 6.1 - Security Principles 6.2 - Risks 6.3 - Impacts 6.4 - Protection Measures 6.5 - Physical Protection 6.6 - Logical Protection

Learn about the advantages and disadvantages to individuals and organisations when using the internet. Based on the 2016 OCR Cambridge Technicals Level 3 IT specification for Unit 2 (Global Information). 1.7 & 1.8 - Internet Pros & Cons Exam Board: OCR Specification: 2016 - Unit 2 The internet has become easier and cheaper to access since the mid 1990s and today it is almost taken for granted. The rise of the internet, and the services it provides, has lead to advantages and disadvantages for both individuals and organisations . Advantages for Individuals Increased speed of personal communication Allows for instant messaging, emails and video chats across the world. Easy access to information The internet has free resources such as CSNewbs and Wikipedia, plus academic journals for research & study. 24/7 access to services Shopping, browsing and banking can be completed when convenient for the user. Social interaction with others Social media, discussion forums and online games provide entertainment and social interaction. Disadvantages for Individuals Potential for identity theft Uploading personal data and storing sensitive information risks hackers obtaining and utilising it. Cost of connection & services Internet service providers (ISPs) charge a monthly fee and equipment like a router needs installation. Cyberbullying & trolling The abuse of others on social media is possible. Anonymisation makes it harder to catch offenders. Spreading misinformation 'Fake news' or biased information can be easily spread on social media and lead to incorrect assumptions. Source of distraction Staff and students may neglect their work and study for entertainment or social media. Advantages for Organisations Share data quickly globally Files and information can be sent instantly to locations across the world. Cloud storage can store data. Online services always available E-commerce businesses can operate 24/7 globally, permit users to browse and accept payments. Easy internal communication Staff can use emails, video calls or instant messages to communicate. Open up the workplace Staff can work from home, on the commute to/from work and outside of the office. Disadvantages for Organisations Malicious attacks & threats Websites can be hacked / taken offline with DDoS attacks. Data can be stolen or corrupted. Cost of maintaining services Most companies require an IT department to oversee device installation and maintenance. Reputation and controversies Companies that leak data will damage their reputations. Social media posts could backfire. Q uesto's Q uestions 1.7 - Internet Pros & Cons: 1. List 5 points for the following categories (you may need to include researched / your own points for some): a. Advantages of the internet for individuals [5 ] b. Disadvantages of the internet for individuals [5 ] c. Advantages of the internet for organisations [5 ] d. Disadvantages of the internet for organisations [5 ] 1.6 - Information Formats Topic List 2.1 - Information Styles

Learn how to add a counter to Greenfoot to keep track of the score. Learn how to add and subtract points to the counter. Part 6 of the Greenfoot Tutorial for the Eduqas / WJEC GCSE 2016 specification. 6. The Counter Greenfoot Tutorial 1. Import the Counter The counter class can be imported into your Greenfoot world. Select Edit in the main Greenfoot window then ' Import Class... ' and choose Counter . Watch on YouTube: The Counter class will appear in the Actor classes list . Right-click on the Counter, choose the ' new Counter() ' option and drag it into the world. Now right-click on the background and select 'Save the World' once you have dragged the counter into the world. 2. Increase the Counter by 1 Two lines of code are required to increase the counter . Add this code when your main character is removing the collectible object . This code allows your main character to access the 'add' method from the Counter class . The method 'add ' just increases the value of the counter by the number in the brackets . To decrease the counter , type a negative value in the brackets, such as -1 . < Part 5 - Play Sounds 3. Compile and Run Click the Compile button at the top of the code editor . Then you can go back to the main Greenfoot window and click Run to test if your counter increases . Click on me if you've got an error that you're stuck with. Part 7 - Extension Ideas >

Learn about the different protocols used on networks - HTTP, HTTPS, TCP, IP, FTP and SMTP. Also learn about protcol layers in the 4-layer TCP/IP model. Based on the J277 OCR GCSE Computer Science specification (first taught from 2020 onwards). 3.2b: Protocols & Layers Exam Board: OCR Specification: J277 Watch on YouTube : IP & MAC Addresses Protocols & Standards Common Protocols Protocol Layers Protocols A protocol is a set of rules that allow devices on a network to communicate with each other . TCP / IP (Transmission Control Protocol / Internet Protocol) TCP / IP is actually two separate protocols that combine together. TCP is a protocol that allows packets to be sent and received between computer systems. It breaks the data into packets and reorders them back into the original data at the destination. IP is a protocol in charge of routing and addressing data packets . This ensures data packets are sent across networks to the correct destination . It is also an addressing system - every device on a network is given a unique IP address so data packets can be sent to the correct computer system. HTTP is used to transfer web pages over the Internet so that users can view them in a web browser . All URLs start with either HTTP or HTTPS (e.g. https://www.csnewbs.com). HTTPS is a more secure version of HTTP that works with another protocol called SSL ( Secure Sockets Layer ) to transfer encrypted data . You should see a padlock symbol in the URL bar if your connection to that website is secure. HTTP/HTTPS (Hypertext Transfer Protocol) Transfer Protocols FTP ( File Transfer Protocol ) is used to transfer files across a network. It is commonly used to upload or download files to/from a web server . SMTP ( Simple Mail Transfer Protocol ) is a protocol used to send emails to a mail server and between mail servers . POP ( Post Office Protocol ) and IMAP (Internet Message Access Protocol ) are both protocols for receiving and storing emails from a mail server. POP will delete an email from the email server once it has been downloaded to a device . Pop! IMAP syncs the message with an email server so it can be accessed by different devices . IP Address & MAC Address There are two versions of IP addressing currently used - IPv4 and IPv6 . IPv4 is a 32-bit address , represented in denary , that allows for over 4 billion unique addresses . It has four 8-bit segments of denary values (from 0 to 255) separated by full stops . IPv4 example: 145.13.218.102 IPv6 is a 128-bit address , represented in hexadecimal , that allows for an undecillion unique addresses . It has eight 16-bit segments of four hexadecimal values (0000 - FFFF), separated by colons . IPv6 example: 736E:1029:A4B3:902D:77B2:72FF:AE62:0912 A MAC address is a unique hexadecimal number assigned to each network interface card/controller inside a networked device such as a router or laptop . A MAC address is a 48-bit address made up of six 8-bit pairs in hexadecimal , separated by dashes . While an IP address may change , the MAC address can’t be changed . MAC stands for Media Access Control . Network Interface Card (NIC) MAC example: 19-C2-D1-47-AA-38 Networking Standards Networking standards are rules that allow computer systems to communicate across networks . Standards have been created to ensure devices can exchange data and work together by interpreting signals in the same way , regardless of the manufacturer . TCP/IP Stack & Layers What is TCP/IP? TCP/IP (Transmission Control Protocol / Internet Protocol ) is a set of protocols that operate on different layers . These two protocols are used together to allow computers to communicate on a network . What is a protocol layer? A layer is a division of network functionality - each layer provides a specific function to assist the transmission of the data that is being sent. TCP/IP is split into four layers (named Application , Transport , Internet and Link ). Important Note: You do not need to know any layer names or the purpose of any specific layers in the OCR GCSE J277 specification , just what layers are and why they’re used . Why are protocol layers used? Layers are self-contained , so they allow different developers to concentrate on one aspect of the network at a time . A layer can be taken out and edited without affecting other layers . Protocol layers are used to visualise the different parts of a network , as each of the four layers of TCP/IP has a specific role and is associated with different protocols . Protocols are broken down into well-defined , specific layers to simplify design , making it easier to identify errors (known as troubleshooting ). Each layer uses specific protocols , so layering ensures these protocols are applied in a specific order . This process uses abstraction and layers only communicate with adjacent layers for easy compatibility . Q uesto's Q uestions 3.2b - Protocols & Layers: 1. Describe each of the following protocols . It might be helpful to also draw an icon or small diagram for each one: a. TCP [ 2 ] b. IP [ 2 ] c. HTTP & HTTPS [ 3 ] d. FTP [ 2 ] e. SMTP [ 2 ] f. POP3 & IMAP [ 2 ] 2. State which protocol would be used in the following scenarios : a. Transferring a music file to a friend over the internet. [ 1 ] b. Sending an email to a family member in America. [ 1 ] c. Using a webpage to enter a password securely. [ 1 ] d. Receiving an email from a bank. [ 1 ] 3a. What are networking standards ? [ 2 ] 3b. What is TCP/IP ? [ 2 ] 3c. What is a protocol layer ? [ 2 ] 3d. Give at least two reasons why protocols are split into layers . [ 4 ] 3.2a - Wired & Wireless Networks Theory Topics 4.1 - Security Threats

Learn about the motherboard, graphics processing unit (GPU), sound card, embedded systems and input / output systems. Based on the 2020 Eduqas (WJEC) GCSE specification. 1.6: Additional Hardware Exam Board: Eduqas Specification: 2020 1.6a - Internal Hardware Motherboard The motherboard is the main circuit board of a computer , unique for each device. It holds and connects the different components together , allowing data to be transferred between them. Components such as the CPU and ROM are directly attached to the motherboard. The motherboard has expansion slots for additional cards (i.e. sound cards) and ports (i.e. USB). Graphics Processing Unit (GPU) Sound Card A GPU is a microprocessor that performs complex calculations to generate graphical images to be displayed on a monitor . There are two types of GPU, integrated GPUs within the motherboard circuitry or dedicated GPUs on an additional card (known as a 'graphics card'). An integrated GPU is cheaper and generates less power because it uses the RAM of the computer . Integrated GPUs are used in tablets and laptops as they generate less heat and are optimal for general computing uses (e.g. web browsing or watching movies). A dedicated GPU is more expensive and generates more heat, often requiring a fan because it contains its own memory . Dedicated cards are used by animation professionals and professional gamers who require the best graphics. Sound cards convert analogue sound waves into digital data (binary) when inputting audio through a microphone. 0010 1011 0101 0101 0110 0111 0101 0001 0101 0010 1011 0101 0101 0110 0111 0101 0001 0101 Sound cards also convert digital data (binary) into analogue sound waves to output audio through speakers or headphones. 1.6b - Embedded Systems Example: A washing machine has a control chip that manages the different program cycles. An embedded system is a computer system built into a larger machine to provide a means of control . Embedded systems perform a specific pre-programmed task which is stored in ROM . An embedded system uses a combination of hardware and software . Example: A traffic light has a control chip that determines when to change to a green or red light. 1.6c - Input & Output Devices Input devices are used by humans to interact with a computer system , through methods such as text , voice or touch . Output devices show the result of computer processing , such as sound , printed text or a visual display on a monitor. Storage devices , such as a USB stick or an external hard drive, are neither input nor output devices - see 1.4 . Input Devices These are just some of the more common input devices . A mouse and a keyboard have been described in further detail. Are there any devices below you haven't heard of before? Mouse Benefits: Easy to navigate a graphical user interface. A wireless mouse takes up less space . Faster to select options (e.g. in a video game). Drawbacks: Difficult to use for people with restricted hand movement . Difficult to use on some surfaces . Other input devices: Scanner Controller Microphone Webcam Chip Reader OCR Scanner OMR Scanner Barcode Scanner Graphics Tablet Sensors (e.g. light or temperature) Touch Screen Remote Control Biometric Scanner (e.g. fingerprint or iris) Concept Keyboard Sip / Puff Switch Keyboard Benefits: Quick to input text . Easy to use with a familiar layout on most keyboards. Keys can be customised and shortcuts can be used . Drawbacks: Takes up a large amount of space on a desk. Difficult for people to use with restricted hand movement or poor eyesight . Output Devices Monitor These are just some of the more common output devices . A monitor and a printer have been described in further detail. Are there any devices below you haven't heard of before? Other output devices: Plotter Speakers Projector Alarm Light Headphones Touch Screen Braille Terminal What is it? A monitor is required to see the result of human input and computer processing . Monitors can be bought in different sizes and resolutions for a range of purposes such as video editing or playing games . Monitors settings can be changed to alter the brightness or contrast . Printer What is it? A printer uses ink or toner to print a document (such as text or images) onto paper . Inkjet printers use ink cartridges , are generally slower and print in a lower quality . Laser printers use toner cartridges and are generally quicker and print to a higher quality . Q uesto's Q uestions 1.6 - Additional Hardware: 1.6a - Internal Hardware 1. What is the purpose of the motherboard ? [2 ] 2a. What is the purpose of the GPU ? [ 2 ] 2b. Describe two differences between integrated and dedicated expansion cards . [ 4 ] 3. Explain how a sound card works. [ 4 ] 1.6b - Embedded Systems 1. What is an embedded system ? [3 ] 2a. Give two examples of an embedded system. [ 2 ] 2b. Research and describe another example of an embedded system. [ 2 ] 1.6c - Input & Out[ut Devices 1. Choose four input devices and describe at least two benefits and two drawbacks of using each one. [ 8 ] 2. Describe three output devices . [ 3 ] 3. Justify which input and output devices would be most suitable in the following scenarios: a. A teacher needs to take the class register . [ 4 ] b. A family want to communicate with their cousins in Australia. [ 4 ] c. The school movie club wants to play Star Wars in the assembly hall. [ 4 ] d. An e-sports player is taking part in an online multiplayer tournament . [ 4 ] e. A laboratory needs security so that only registered scientists can enter. [ 4 ] 1.5 - Performance 2.1 - Logical Operators Theory Topics

Learn about the denary, binary and hexadecimal number systems and how to convert between them. Based on the 2016 OCR Cambridge Technicals Level 3 IT specification. 1.8 & 1.9 - Number Systems & Conversion Exam Board: OCR Specification: 2016 - Unit 1 What is binary? What is denary? Denary (also known as decimal ) is the number system that you've been using since primary school. Denary is a base 10 number system. This means that it has 10 possible values - 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9 . How to convert from binary to denary: How to convert from denary to binary: What is hexadecimal? Hexadecimal is a base 16 number system. This means that it has 16 possible values - 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E and F . Hexadecimal is used as a shorthand for binary because it uses fewer characters to write the same value . This makes hexadecimal less prone to errors when reading or writing it , compared to binary. For example, 100111101011 is 9EB. Hexadecimal only uses single-character values. Double-digit numbers are converted into letters - use the table on the right to help you understand. How to convert from binary to hexadecimal: How to convert from hexadecimal to binary: Converting from denary to hexadecimal / hexadecimal to denary To convert from denary to hexadecimal or the other way round you must convert to binary first . Denary > Binary > Hexadecimal Hexadecimal > Binary > Denary Use the videos on this page if you need help converting to or from binary. The most common number systems question in exams are from denary to hexadecimal or from hexadecimal to denary so make sure that you practice these conversions. Q uesto's Q uestions 1.8 & 1.9 - Number Systems: 1. Explain why hexadecimal numbers are used as an alternative to binary . [ 2 ] 2. Convert the following values from binary to denary : a. 00101010 b. 11011011 c. 01011101 d. 11101110 e. 01011111 [1 each ] 3. Convert the following values from denary to binary : a. 35 b. 79 c. 101 d. 203 e. 250 [1 each ] 4. Convert the following values from binary to hexadecimal : a. 11110101 b. 01100111 c. 10111010 d. 10010000 e. 11101001 [1 each ] 5. Convert the following values from hexadecimal to binary : a. C2 b. 8A c. DE d. 54 e. F7 [1 each ] 6. Convert the following values from denary to hexadecimal : a. 134 b. 201 c. 57 d. 224 e. 101 [1 each ] 7. Convert the following values from hexadecimal to denary : a. 32 b. A5 c. 88 d. C0 e. BE [1 each ] Watch on YouTube Watch on YouTube Watch on YouTube Watch on YouTube By now you should know that computer systems process data and communicate entirely in binary . Section 1.7 explained different binary storage units such as bits (a single 0 or 1), nibbles (4 bits) and bytes (8 bits). Binary is a base 2 number system. This means that it only has 2 possible values - 0 or 1 . Click the banners above to try self-marking quizzes (Google Form) on these topics. Denary to Binary: Binary to Denary: Binary to Hexadecimal: Hexadecimal to Binary: 1.7 - Units of Measurement Topic List 2.1 Software Types

Learn about data structures including arrays, records, lists, tuples, linked-lists, graphs, stacks, queues, trees, binary search trees and hash tables. Based on the OCR H446 Computer Science A-Level specification. Exam Board: OCR A-Level 4.2 - Data Structures Specification: Computer Science H446 Watch on YouTube : Arrays Records Lists & tuples Stacks Queues Linked lists Trees Graphs Hash tables Data structures are used to organise and store data so it can be accessed and processed efficiently , often through the use of an index or reference . They can be static , meaning their size is fixed during program execution , or dynamic , allowing them to grow or shrink as data changes . Arrays An array is a data structure that stores a collection of items of the same data type , with each item accessed using an index . A one-dimensional (1D ) array is a simple sequence of values , such as test scores for a single person : scores = [12, 15, 18, 20] . A two-dimensional (2D ) array is like a table or grid , made up of rows and columns - for example, storing a timetable or test scores for a class . A three-dimensional (3D ) array stores data in multiple layers , like a series of 2D grids . For example, test scores for a class across multiple subjects . This page is under active development. Check here for the latest progress update. YouTube video uploading soon Records A record groups together related but different types of data under one name . Each individual piece of data within a record is called a field and each field can have a different data type (e.g. string , integer , Boolean ). For example, a student record might include fields such as Name (string ), Age (integer ) and Enrolled (Boolean ). Records are often used in databases or programming to represent real-world entities where multiple attributes need to be stored together . YouTube video uploading soon Lists & Tuples A list stores an ordered collection of items , which can be changed (mutable ) after creation. Items in a list can be added , removed or modified , and they can be of different data types . For example, in Python : myList = [10, "apple", True] . A tuple is similar to a list but is immutable , meaning its contents cannot be changed once created . Tuples are often used for fixed sets of data that should not be altered , such as coordinates or dates . For example: myTuple = (3, 5, 7) . YouTube video uploading soon 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 Graphs A graph is made up of nodes (also called vertices ) connected by edges and is used to represent relationships between items. Graphs can be directed , where edges have a specific (one-way) direction , or undirected , where connections go both ways . They can also be weighted , where edges have values such as distance or cost , or unweighted , where all connections are equal . Graphs are widely used in computing, for example, in social networks (users and friendships ), maps (locations and routes ) and network routing algorithms . YouTube video uploading soon Hash Tables A hash table stores key–value pairs and allows for very fast data access . It uses a hash function to convert a key (such as a name or ID ) into an index (hash value ), which determines where the associated data (value ) is stored in memory . When retrieving data , the same hash function is applied to the key to find the value’s location instantly , making lookups close to constant time complexity on average . If two keys produce the same hash (a collision ), techniques such as chaining or linear probing are used to handle it . Hash tables are commonly used in databases , caches and programming languages for tasks like fast searching and indexing . YouTube video uploading soon Q uesto's K ey T erms Arrays: array, 1-dimensional, 2-dimensional, 3-dimensional, static Records: record, field, data type, primary key Lists and Tuples: list, tuple, mutable, immutable, dynamic 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 & Graphs: tree, binary tree, binary search tree, root node, branch, graph, weights, directions Hash Table: hash table, key, value, collision, linear probing, chaining D id Y ou K now? Trees are used for dialogue options in narrative video games , displaying possible paths based on the player’s previous choices . The final ' suicide mission ' of Mass Effect 2 has hundreds of possible variations depending on ship upgrades , squad member loyalty , and assigned roles during the last mission . 4.1 - Data Types A-Level Topics 4.3 - Boolean Algebra

Learn how to use App Inventor 2 to create simple programs. Try to complete task 3 on this page. Perfect for Key Stage 3 students to experiment with block coding, objects and properties. App Inventor Task 3 - Munchin' Pizza This page will teach you how to make a simple app that changes pictures when a button is pressed . You can make the app more complex by adding sounds or additional buttons. Step 1: Set up App Inventor 2 Open App Inventor 2 (use the button on the right) and create a new project. You will need to log in with a Google account. Download the picture images from the zipped folder on the App Inventor 2 Basics page here . Once you have downloaded the pizza pictures you will need to upload them. Find the Media tab on the right side of App Inventor and click 'Upload File...' You will need to upload each picture individually. In the Palette tab on the left side, drag two buttons into the middle screen so they look like this: In the Components tab on the right, click on Button1 and click the Rename button at the bottom to change it to Pizza . Then Rename Button2 to Munch . This will help us when we code later as it will be less confusing. Click on the second button (Munch) that you just dragged into the centre then look in the Properties tab on the right and scroll down to Text . Change 'Text for Munch' to something like 'Munch Pizza' . Now click on the first button in the centre (Pizza) and in the Properties tab, click on Image and select the first image. It should be the full slice of pizza. When you have set the image, you might notice it goes a bit crazy. Still in the Properties tab, change the Height and Width to 'Fill parent...' for both. This will make the image fit within the boundaries of the screen. Finally, change the Text for the Pizza button to be blank. Otherwise it will appear on top of the pizza and look odd. So far you should have a button disguised as a pizza and another button that tells you to munch that lovely cheesy deliciousness. If your program does not look like this, read the instructions above again carefully. Step 2: Code Click on the Blocks button in the top right to start adding code. In the Blocks tab on the left side click on Munch and drag the when Munch Click block into the centre. This block will execute any code inside of it whenever the munch button is clicked. In the Blocks tab on the left side click on Logic and drag an if then block and snap it inside the block you just dragged over. Click on the blue cog button and drag four else if blocks inside the if block at the bottom. The blocks at the top will automatically update when you drag the blocks under the if block underneath. Because we are using different images, we need to check which image is currently being displayed, so we know which picture to change to. Firstly we want to check if the first image is being displayed. Connect an = block from the Logic section. Then add a Pizza Image block from the Pizza section. Lastly grab a " " block from the Text section and write the name of your first image inside (e.g. pizza1.jpg) Don't forget the extension (.jpg). But what does this code actually mean? It is checking to see what the current pizza image is. And if it is pizza1.jpg then it is going to... ...change the picture to pizza2.jpg, as if someone has munched the pizza! Grab a set Pizza Image to block from Pizza and then snap another " " block from Text and add the pizza2.jpg text inside. Now that we have written the code to check the current picture and move it to the next one when pressed, we just need to copy this for the other four pizza pictures. Rather than select all the blocks again, right-clicking on the blocks and selecting 'Duplicate' will copy them. Copy each block and then change the values so that if pizza2.jpg is the current image, then it sets it to pizza3.jpg and so on. Make sure that pizza5.jpg sets the image to pizza1.jpg so that it goes round in a loop. Program 3 Complete! Step 3: Run The easiest way to run an app that you have created at home using App Inventor 2 is to download the free MIT AI2 Companion App on your smartphone from the Google Play Store . At the top of the App inventor program on your computer , click on Connect and AI Companion . This will generate a six-digit code you can type into your phone. If your school has the emulator installed, you can also use this to test your app. Extra Step: Challenges 1. Create your own images and upload them . You can easily create your own set of pictures and link them together. Why not try: Eating a different type of food (e.g. cookie or doughnut). A simple scene that changes from night to day. A simple character that changes appearance (like Pikachu powering up a thunder strike with each button press). 2. Add a sound effect whenever a button is pressed . In the video at the top of the page, you'll see I have a 'munch' sound whenever the button is pressed. You could record this sound yourself or use a sound effect site. Once you have got your sound file (it should be short and .mp3) you need to upload it, just like you uploaded your images. In the Designer layout click 'Upload file...' in the Media tab on the right. Then look in the Palette tab on the left side, open the Media section and drag a Sound block into the centre. It will appear underneath the phone screen in a section called 'non-visible components' which is fine. Now click on Properties on the right side and choose the sound file you just uploaded in the Source box. Click on the Blocks button in the top right to start adding the code! In the Blocks tab on the left side, click on Sound1 and drag the call Sound1 Play block directly underneath when Munch click . This will play the sound everytime the button is pressed. 3. Add more buttons . You could add a second clickable button which reverses the pattern and a third button that resets the order back to the first image. Adding new buttons is easy - drag them from the Palette tab in the Designer layout. Change the button text in the Properties tab and the name of the button in the Components tab. To add code, click on Blocks in the top right then you can duplicate the code for Munch by right-clicking and choosing Duplicate. Now just change the values to what you want. If you are making a reset button, you don't need an if then statement, just set the image to your first image when the button is clicked. Keep messing around with the program and have fun! KS3 Home Tasks 4, 5 & 6

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