Lesson Notes By Weeks and Term v5 - Grade 8

Lesson Video

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Performance objectives

• Identify the basic elements of a communication system.
• Explain the importance of graphic communication.
• Describe different graphic communication techniques like sketching, technical drawing, and CAD.
• Apply basic sketching techniques for simple drawings.
• Understand why clear communication is vital in technical drawings.

Lesson summary

Communication is fundamental to how we interact with the world. From sharing news about a local stokvel to understanding instructions for assembling a new braai stand, communication systems are essential. Graphic communication, in particular, plays a crucial role in conveying information visually, making it easier to understand and remember. Think of road signs guiding taxis in Durban, pamphlets advertising spaza shops in Soweto, or even the warning labels on electrical appliances – these are all examples of graphic communication in action. Understanding how these systems work empowers us to be better communicators and more discerning consumers of information.

Lesson notes

2.1 The Basic Communication System A communication system is a process that involves transferring information from one point to another. It's like a conversation, but it can also be a one-way flow of information.

The basic elements are: Sender: The person or device that initiates the communication. For example, a radio station broadcasting a news report about load shedding.

Message: The information being conveyed. This could be a news report, an instruction manual, or even just a friendly greeting.

Channel: The medium through which the message is transmitted. This could be radio waves, a printed page, a computer network (like WhatsApp), or even spoken words.

Receiver: The person or device that receives the message. This could be someone listening to the radio, reading a textbook, or using a computer.

Feedback: The response from the receiver to the sender, indicating that the message has been received and understood (or not). This could be a nod of agreement, a question for clarification, or even a change in behaviour. The absence of feedback doesn't necessarily mean communication didn't occur; the receiver might just not provide feedback.

Example: Imagine a shebeen owner (sender) wants to advertise a special on amagwinya (message) to attract more customers. They create a hand-painted sign (channel) and display it outside their shebeen. Potential customers (receivers) see the sign and some decide to buy amagwinya. The increased sales (feedback) tell the shebeen owner the sign is effective. 2.2 Graphic Communication Graphic communication uses visual elements to convey information. It's a powerful tool because humans are visual creatures and often process images faster and more effectively than text alone.

Graphic communication includes: Drawings: These can be freehand sketches, technical drawings, or computer-generated images.

Diagrams: These use symbols and lines to show how things work or how they are related.

Charts and Graphs: These present numerical data visually, making it easier to understand trends and patterns. Think of COVID-19 case number graphs during the pandemic.

Photographs: Realistic images can be very effective in communicating information.

Symbols and Icons: Standardized symbols can quickly convey information across language barriers (e.g., road signs). 2.3 Graphic Communication Techniques Sketching: Freehand drawing used to quickly capture ideas and explore designs. It's often the first step in the design process. Sketching is used extensively in brainstorming initial furniture designs, building layouts, or visualizing simple machine concepts.

Techniques:* Use light lines, focus on proportions, practice different line weights to create depth and emphasis.

Technical Drawing: Precise drawings that show the exact dimensions and specifications of an object. These are used by engineers, architects, and manufacturers to build and assemble products. Think of the blueprints used to build a house. Technical drawing utilizes specific line types (visible lines, hidden lines, center lines), dimensions, and notes.

Orthographic Projection:* A common method where an object is represented by multiple 2D views (front, top, side) that show its different faces.

Isometric Projection:* Shows a 3D representation of an object, making it easier to visualize.

Computer-Aided Design (CAD): Using computer software to create technical drawings and 3D models. CAD offers greater precision and allows for easy modification and sharing of designs. Think of architects designing complex buildings using CAD software. Some popular CAD packages include AutoCAD, SketchUp, and Fusion

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0. Example (Technical Drawing): Imagine you want to build a simple wooden bench for your school's garden.

A technical drawing would include: Orthographic Projections: Front View:* Shows the height and width of the bench.

Top View:* Shows the length and width of the bench.

Side View:* Shows the height and depth of the bench.

Dimensions: Precise measurements for all parts of the bench (length of the legs, width of the seat, etc.) in millimeters (mm).

Materials: Specification of the type of wood to be used (e.g., pine, treated timber).

Notes: Any special instructions (e.g., "Use waterproof glue for assembly"). This detailed drawing ensures that anyone can build the bench accurately, even if they haven't seen the original design. Guided Practice (With Solutions)

Question 1: Identify the elements of a communication system in the following scenario: A school principal announces on the public address system (loudspeaker) that there will be a school assembly tomorrow. The students hear the announcement and start talking about it.

Solution: Sender: School Principal Message: Announcement about the school assembly Channel: Public address system (loudspeaker)

Receiver: Students Feedback: Students talking about the announcement

Commentary: This question reinforces the understanding of the basic elements of a communication system.