This unit introduces students to the binary digits that lie beneath the images and sounds of the digital media that is all around them.
Just like in the previous unit, where students examined characters and numbers, the ideas that students need to understand are not really new to them. You will draw on familiar examples of composing images out of individual elements, mixing elementary colours to produce new ones, and taking samples of analogue signals to illustrate these ideas and bring them together in a coherent narrative.
The unit also has a significant practical aspect using editing software for both images and sound (detailed worksheets are included for GIMP and Audacity). Students manipulate images and sounds to gain an understanding of the underlying principles of digital representation.
The unit resources include a useful learning graph (.jpg file) to show how the unit content is sequenced - see this link https://blog.teachcomputing.org/approaches-to-developing-progression for an explanation.
This unit builds on the Year 8 unit, ‘Representations: from clay to silicon’.
Tracing the steps of a hiker through the altitude data that she transmits, students will familiarise themselves with the basic concepts necessary for understanding any analogue to digital conversion: samples, sampling rate, and sample size.
The main goal is for students to understand the ‘big picture’ of how...
First, students will revisit the digitisation process, in order to understand how the sampling rate and the sample size affect the size and quality of the representation. Next, they will use a sound editing program that will allow them to experiment with sound to complete specific tasks and challenges.
To conclude the unit, students will spend half the lesson completing a summative assessment.
In the time remaining, students will be introduced to alternative (symbolic) representations for images and sound, such as vector graphics and MIDI music. They will also be introduced to what compression is and why...