Pixels and binary digits
About this lesson
Students are given a bitmap image made up of coloured pixels. They explain how the image is made up of binary digits that represent each pixel. Students represent 8 colours using binary digits. Teachers assess the student’s demonstrated knowledge/skills using the checklist provided.
Year band: 5-6Achievement Standard
By the end of Year 6, students explain the fundamentals of digital system components (hardware, software and networks) and how digital systems are connected to form networks. They explain how digital systems use whole numbers as a basis for representing a variety of data types.
Students define problems in terms of data and functional requirements and design solutions by developing algorithms to address the problems. They incorporate decision-making, repetition and user interface design into their designs and implement their digital solutions, including a visual program. They explain how information systems and their solutions meet needs and consider sustainability. Students manage the creation and communication of ideas and information in collaborative digital projects using validated data and agreed protocols.
This task can be used for formative assessment purposes or as a summative assessment to assess what students have learned as a result of investigating bitmap images, in particular, the way in which binary digits are used to encode individual pixels of an image.
Provide students with the handout: Pixels and binary digits.
Use the handout: Pixels and binary digits to find out what students now about pixels and the way an image is coded using binary. Ask them to explain the relationship between the image and the grid that contains the 3 digit binary numbers.
To what extent:
- Are students aware that if the grid was made up of only 1 binary digit (a 1 or a 0) then the image would be made up of black or white pixels?
- Do they know what the binary numbers represent ie 111 is white?
- Can they work out how to create their own image by encoding the grid using binary digits?
To what extent:
- Do they correctly explain the relationship between the coloured pixels and the 3 digit binary numbers?
- Can they correctly match the coloured pixel to the correct 3-digit binary number?
- Can they work out the remaining three bit binary numbers that where not used in the bitmap image?
- Can they create their own image by encoding the grid using binary digits?
- Can they decode someone else’s encoded grid to produce the relevant image made up of?
Use the assessment checklist provided to record comments for each student.
Relevant Revised Blooms taxonomy
The key active verbs used in the Australian Curriculum: Digital Technologies have been aligned to Bloom’s Revised Taxonomy.
In this task students explain and represent. The related Revised Blooms taxonomy are:
- (explain) Make (an idea or situation) clear to someone by describing it in more detail or revealing relevant facts (ACARA).
- (represent) Use words, images, symbols or signs to convey meaning (ACARA).
This assessment checklist provides a guide to record the student's demonstrated skills and knowledge.
Word and pdf versions of the checklist can be downloaded in the resources section.
|Demonstrated knowledge/skills||Yes/No or progressing||Comments|
The student explains the way an image is encoded using binary data.
The bitmap image provided is used to explain how binary digits are combined to create a coloured pixel.
The student can create their own bitmap image by encoding a grid using binary bit representation.