Flow of Activities
Activity Binary system
How does a computer encode text?
Australian Curriculum Alignment
- Representation of data (ACTDIK024)
What's this about?
All computer data is represented using binary notation - a number system that uses 0s and 1s. Binary digits can be grouped together into bytes.
All software, music, documents, and any other information that is processed by a computer is stored using binary.
Two standard character sets that students should become familiar with are ASCII and Unicode. In each standard a certain sequence of bits (1s and 0s) stands for a letter or other character.
ASCII is only used for the English language. Unicode uses between 8 and 32 bits per character, so it can represent characters from languages from all around the world.
Hexadecimal is way to write binary numbers more easily. An 8-bit binary number can be written using only two different hex digits.
Learning tasks
- All number systems rely on positional notation. To understand binary numbers first be familiar with the positional notation we use every day with decimal notation.
- Provide students opportunities to code and encode messages using ASCII, Unicode and Hexadecimal. Simple conversions can be done between each.
- Students could present to the class ‘Why Unicode was developed’.
Explore implementing a digital solution that demonstrates how to control appliances, and to investigate home automation. Examples may include programming a binary switch using (0 and 1) as input for off and on, or detecting speech and recognising a command to turn the appliance on or off.
Supporting Resources
Positional notation and Number Bases
This video explains positional number using base 10 and then base 2.
Why Do Computers Use 1s and 0s
A short explanation of binary.
Binary numbers and place value
An introduction to converting binary numbers into decimal.
What are binary numbers?
James May explains binary numbers.
Representing Numbers and Letters with Binary
How To Convert Binary To Decimal Tutorial
A simple tutorial outlining elementary conversions of binary to decimal and decimal to binary.
Intro to Binary Numbers
Learn to count in binary, the language of computers.
Binary Counter
This video shows a wooden binary counter to demonstrate the binary numbers from 0 to 63 (in base 10).
Introduction to binary
Use this guide for students who are unfamiliar with binary or as a refresher.
Hexadecimal
An interactive guide to explore hexadecimal system. It is important to note that computers do not use hexadecimal - it is used by humans to shorten binary to a more easily understandable form.
A shorthand way of writing binary numbers: Hexadecimal
Hexadecimal is a shortcut for representing binary. It is used because large numbers can be difficult to work with in binary.
How To Easily Convert Hexadecimal To Binary And To Decimal Tutorial
A simple tutorial outlining elementary conversions of hexadecimal to decimal, through converting the hexadecimal to binary first.
Hexadecimal Number System
Learn how the Hexadecimal Number System works.
Creating my own spreadsheet to convert binary to decimal
This lesson provides some guidance and Excel files for student and teacher use to convert up to 8-bit binary numbers to a decimal.
B4 Computer Processor Kit
The B4 is a modular computer processor kit and accompanying study guide. It has been designed to help students explore the fundamental operation of computers as part of the new Australian Curriculum: Digital Technologies.
Lesson Ideas
Everything is numbers
A lesson idea about representing data as text, images and sound.
Home automation programming
Investigate home automation systems, including those powered by artificial intelligence (AI) with speech recognition capability.
Assessment
Suggested approaches may include
- Presentation or demonstration
- Worksheets and quizzes that demonstrate the ability to convert binary to decimal, decimal to binary.
- Worksheets and quizzes that demonstrate the ability convert hexadecimal numbers to binary and/or decimal formats.
Assessment Resources
Binary (text, image, audio) student work samples
View these works samples created by Joanne Villis from students response to the task: create a video using any program you like, with the intention of explaining binary for text, image and sound for a peer.
Designing and implementing a podcast
Students designed and implemented a podcast and documented the process. They identified the audience, designed and planned the solution including creating a storyboard and script. Students implemented the solution using audio software, evaluated the solution and managed the upload of the file using email and file conversion software to a wiki.
Activity Bitmap images
How are images encoded?
Australian Curriculum Alignment
- Representation of data (ACTDIK024)
What's this about?
All computer data is represented using binary notation - a number system that uses 0s and 1s. Binary digits can be grouped together into bytes.
Images onscreen are made up of picture elements (pixels). Bitmap images are organised as a grid of pixels. Each pixel is stored as a binary number and represents a specific colour.
The colour depth is measured in bits. 1 bit per pixel allows for two values (1) white or (0) black. 3 bits per pixel results in 8 available colours in combinations of RGB (000, 001, 011, 100, 101, 111, 110, 111). 8 Bit colour allows for 256 colours.
Commonly images are made up of colours that are a combination of 24 bits. For example, green can be represented in binary as 000000001111111100000000 or in RGB as (0, 255, 0) and as hexadecimal #00FF00. 24-bit colour makes 16,777,216 (256 x 256 x 256) possible colours.
Learning tasks
- Provide online tools that enable students to explore creating images by changing pixels based on a combination of binary digits.
- Introduce hexadecimal as a way to encode pixels.
- Students may explore vector graphics and bitmap graphics and scalability. Explore file formats used to store images.
- Relate the RGB values to other areas where students may be familiar with this use of binary numbers such as when programming an LED on an Arduino board to light up a specific colour or when using Sphero and selecting a particular colour.
Vector and Raster
- There is a difference between these types of graphic images and the file formats used. You may decide to explore this in more detail.
Supporting Resources
Images, Pixels and RGB
Hear Instagram co-founder explain how images are represented in binary, and how image filters work on the inside.
What are Pixels and how do they work?
A basic introduction to what a pixel is, and how it is used to display images, video and content on our screens.
Encoding images
An interactive guide to encoding images.
Images and colours in the CS Field Guide
Section 5.5 explains Images and Colours and representing a colour with bits (binary digits).
What are Vector and Raster Graphics?
Use this video to explain the difference between vector and raster graphics.
The Difference Between Raster and Vector Files & Different File Types
This video explains the difference between raster and vector files.
Colour pixilation tutorial
An online tool that enables students to explore creating images by changing pixel values in binary and hexadecimal.
Pixel Value Interactive
Upload your own photos to see the RGB values for each pixel written as 24-bit colour. For example, a blue pixel may be made up of the RGB value (42, 104, 213). Relate these values back to 8-bit binary equivalent eg 42 = 00101010.
Lesson Ideas
Assessment
Suggested approaches may include
- Artefact Analysis
- Adapted worksheet
- A presentation to explain how RGB values and hexadecimal numbers are used in image manipulation software.
Activity Encoding audio
How does a computer encode audio files?
Australian Curriculum Alignment
- Representation of data (ACTDIK024)
What's this about?
Sounds created on a computer exist as digital information encoded as audio files.
An audio file format is a file format for storing audio. Common audio file formats include MP3, AAC, WMA, FLAC, ALAC, WAV, AIFF, and PCM.
Learning tasks
- Investigate audio file formats, such as MP3, AAC, WMA, FLAC, ALAC, WAV, AIFF, and PCM. How do they differ? Make a list of audio files that students use on their devices. Do this as a group activity and share findings as a class.
- Use audio recording software such as RecordPAd or Audacity to record an audio soundtrack.
- There are several tools that convert between different formats. Use Audacity or similar software to save audio projects in different file formats.
- Explore and analyse the quality of text to speech for example:
- audio books
- a Smartphone that enables spoken messages to send as an SMS.
- A software assistant that uses voice queries to perform actions on a smartphone eg SIRI.
- This activity links with programming. App Inventor or App Lab are free, cloud-based services that enable users to build apps in the web browser. Create an App that uses the functionality of Text to Speech. Consider what prompts the user to speak and what code blocks/code translate.
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Explore implementing a digital solution that demonstrates how to control appliances, and to investigate home automation. Examples may include programming a binary switch using (0 and 1) as input for off and on, or detecting speech and recognising a command to turn the appliance on or off. Alternatively students record an audio file and incorporate this into their computer program. |
Supporting Resources
Encoding audio and video
Use these guides to learn about digital audio and video that has a sample rate, bit depth and bit rate.
Codecs and Formats Explained! (And Why You're Probably Wrong)
A video explaining codecs.
Digital Compression explained by Aloe Blacc
Singer/songwriter Aloe Blacc has built his own sites and created digital pop hits. In this video, he explains how digital compression works.
File Formats and CODECs
This video explains the main three types of compression and their differences, how lossless compression.
Making mobile Apps with App Inventor
You can make an app that has ‘Text to Speech’ functionality. Find out how by following this video tutorial.
App Lab
Code.org’s App Lab is a programming environment where you can make simple apps. Design an app, code in JavaScript with either blocks or text, then share your app.
Convert text to speech
Explore text to speech. Type in text and save as an audio file.
App inventor course
A course that targets beginners to design an app using App Inventor.
App inventor: Getting started
Set up instructions and tutorials to use App inventor. It is important to read the setup instructions. The resulting app is only for Android devices. An emulator needs to be installed on non-Android devices. There is quite a bit of setting up to do to ensure the emulator runs the latest version
Hexadecimal Drum Machine
Use this interactive drum machine to explore turning binary numbers into sound. (View in IE requires Flash)
Lesson Ideas
Assessment
Suggested approaches may include
- Adapted worksheet
- Record audio and save the recording in different formats. Use a tabular display to demonstrate how the different codecs lead to different file sizes.
- Make the Text to Speech app using Appinventor. Demonstrate the completed app
Activity Accessible webpage
How can I design a website that is accessible to users?
Australian Curriculum Alignment
What's this about?
Many computers and mobile devices today have built in text-to-speech software. Some people with disabilities, including people who are blind, use specialized software called screen readers.
Screen readers provide important functionality such as navigating through headings, speaking image alternatives, and identifying internal and external links. They can also highlight the text as it is being read aloud for people to see and hear the content at the same time. Content must be coded properly so that all of the functionality of the text-to-speech software works with the content.
Learning tasks
- Create a website that incorporates images, texts and audio support for text.
- Build empathy as part of the design process to describe needs of different audiences that may require audio support.
- Define the functional and data requirements based on user needs.
- Explore the use of embedded and linked media elements.
Lesson Ideas
Web Accessibility Perspectives: Text to Speech
Web accessibility is essential for people with disabilities and useful for all. Learn about the impact of accessibility and the benefits for everyone in a variety of situations.
Web Accessibility Perspectives: Voice Recognition
Learn more about web accessibility and why it is essential for people with disabilities and useful for all.
Web Accessibility Tutorials
These tutorials shows how to develop web content that is accessible to people with disabilities, and that provides a better user experience for everyone.
10 Free Screen Readers For Blind Or Visually Impaired Users
VoiceOver on the MAC
This is built-in functionality on a MAC. It is in the Utility applications folder.
Ten Guidelines To Improve The Usability And Accessibility Of Your Site
Assessment
Suggested approaches may include
- Design plan
- Artefact analysis