# offset image lesson shift an image horizontally across the display with offset. ### @video td/videos/offset-image-0 ## Topic **If** Conditionals ## Quick Links * [tutorial](/lessons/offset-image/tutorial) * [quiz](/lessons/offset-image/quiz) * [quiz answers](/lessons/offset-image/quiz-answers) * [challenges](/lessons/offset-image/challenges) ## Class Year 7 ## Prior learning/place of lesson in scheme of work Learn how to offset image with a conditional **If**, `if condition then` to run code depending on whether a condition is true or not. We will be learning how to offset image using a local variable, forever loop, the conditional If, input on button pressed, as well as simple commands, such as show string, create image and image show image. ## What the teacher needs to know * Algorithm: An unambiguous set of rules or a precise step-bystep guide to solve a problem or achieve a particular objective. * Command: An instruction for the computer to execute, written in a particular programming language. * Computational thinking: Thinking about systems or problems in a way that allows computer systems to be used to model or solve these. * Data: A structured set of numbers, possibly representing digitised text, images, sound or video, which can be processed or transmitted by a computer, also used for numerical (quantitative) information. * Decomposing: The process through which problems or systems are broken down into their component parts, each of which may then be considered separately. * Hardware: The physical systems and components of digital devices; see also software. * Loop: A block of code repeated automatically under the program’s control. * Programmable toys: Robots designed for children to use, accepting input, storing short sequences of simple instructions and moving according to this stored program. * Program: A stored set of instructions encoded in a language understood by the computer that does some form of computation, processing input and/or stored data to generate output. * Repetition: Executing a section of computer code a number of times as part of the program. * Script: A computer program typically executed one line at a time through an interpreter, such as the instructions for a Scratch character. * Selection: A programming construct in which one section of code or another is executed depending on whether a particular condition is met. * Sequence: To place program instructions in order, with each executed one after the other. * Simulation: Using a computer to model the state and behaviour of real-world (or imaginary) systems, including physical or social systems; an integral part of most computer games. * Variables: A way in which computer programs can store, retrieve or change data, such as a score, the time left, or the user’s name. **QuickStart Computing Glossary ## Documentation * ** global variables ** : [read more...](/js/data) * ** assignment operator ** : [read more...](/reference/variables/assign) * ** forever ** : [read more...](/reference/basic/forever) * ** If ** : [read more...](/reference/logic/if) * **show string** : [read more...](/reference/basic/show-string) * **create image** : [read more...](/reference/images/create-image) * **show image** : [read more...](/reference/images/show-image) * **on button pressed** : [read more...](/reference/input/on-button-pressed) ## Resources * Activity: [tutorial](/lessons/offset-image/tutorial) * Activity: [quiz](/lessons/offset-image/quiz) * Extended Activity: [challenges](/lessons/offset-image/challenges) ## Objectives * learn how to a create a global variable as a place where you can store and retrieve data, accessible across functions and in nested code blocks * learn how to set and change the value of a global variable * learn how to repeat code in the background forever * learn how to conditionally run code depending on whether a condition is true or not * learn how to show a string on the LED screen * learn how to create an Image to show on the micro:bit's LED screen * learn how to show an Image on the micro:bit's LED screen * learn how to run code when an input button is pressed ## Links to the National Curriculum Programmes of Study for Computing ## Progression Pathways / Computational Thinking Framework #### Algorithms * Designs solutions (algorithms) that use repetition and two-way selection, ie if, then and else.(AL) * Uses diagrams to express solutions.(AB) * Uses logical reasoning to predict outputs, showing an awareness of inputs (AL) * Designs solutions by decomposing a problem and creates a sub-solution for each of these parts. (DE) (AL) (AB) * Recognises that different solutions exist for the same problem (AL) (AB) Understands that iteration is the repetition of a process such as a loop (AL) * Represents solutions using a structured notation (AL) (AB) #### Programming & Development * Creates programs that implement algorithms to achieve given goals (AL) * Declares and assigns variables(AB) * Uses post-tested loop e.g.‘until’,and a sequence of selection statements in programs,including an if,then and else statement(AL) * Understands the difference between, and appropriately uses if and if, then and else statements(AL) * Uses a variable and relational operators within a loop to govern termination (AL) (GE) * Uses a range of operators and expressions e.g. Boolean, and applies them in the context of program control. (AL) * Selects the appropriate data types(AL) (AB #### Data & Data Representation * Uses filters or can perform single criteria searches for information.(AL) * Performs more complex searches for information e.g. using Boolean and relational operators(AL) (GE) (EV) * Defines data types: real numbers and Boolean (AB) #### Hardware & Processing * Knows that computers collect data from various input devices, including sensors and application software (AB) #### Communication Networks * Demonstrates responsible use of technologies and online services, and knows a range of ways to report concerns Understands how search engines rank search results (AL) #### Information Technology * Collects, organizes, and presents data and information in digital content (AB) * Makes appropriate improvements to solutions based on feedback received, and can comment on the success of the solution (EV) * Recognises ethical issues surrounding the application of information technology beyond school. Computational Thinking Concept: AB = Abstraction; DE = Decomposition; AL = Algorithmic Thinking; EV = Evaluation; GE = Generalisation ## Activity * time: 20 min. * [tutorial](/lessons/offset-image/tutorial) * [quiz](/lessons/offset-image/quiz) ## Extended Activity * time: 20 min. * [challenges](/lessons/offset-image/challenges) ## Homework * Extended Activity: [challenges](/lessons/offset-image/challenges) ## Intended follow on Publish script to the classroom.