Agricultural Technology May June 2024 MG Eng

SENIOR CERTIFICATE EXAMINATIONS/ NATIONAL SENIOR CERTIFICATE EXAMINATIONS AGRICULTURAL TECHNOLOGY MAY/JUNE 2024 MARKING GUIDELINES MARKS: 200 These marking guidelines consist of 17 pages. . Copyright reserved Please turn over

Agricultural Technology 2 DBE/May/June 2024 SC/NSC – Marking Guidelines SECTION A QUESTION 1 1.1 1.1.1 D✓✓ 1.1.2 A✓✓ 1.1.3 D✓✓ 1.1.4 C✓✓ 1.1.5 C✓✓ 1.1.6 C✓✓ 1.1.7 C✓✓ 1.1.8 A✓✓ 1.1.9 C✓✓ 1.1.10 A✓✓ (20) 1.2 1.2.1 Tin. ✓✓ 1.2.2 water. ✓✓ 1.2.3 flame. ✓✓ 1.2.4 Teflon. ✓✓ 1.2.5 Nickel. ✓✓ (10) 1.3 1.3.1 G✓✓ 1.3.2 D✓✓ 1.3.3 B✓✓ 1.3.4 E✓✓ 1.3.5 C✓✓ (10) TOTAL SECTION A: 40 Copyright reserved Please turn over

Agricultural Technology 3 DBE/May/June 2024 SC/NSC – Marking Guidelines SECTION B QUESTION 2: MATERIALS AND STRUCTURES 2.1 2.1.1 Why chromium is a suitable alloy for the manufacturing of milk tanks. • Increases resistance against corrosion. ✓ • Promotes the hardening of steel.✓ • Improves strength.✓ • Improves resistance to the formation of scale.✓ • Improves tensile strength.✓ • Most chromium steels can be welded well.✓ (Any 3) (3) 2.1.2 An alloy element, other than chromium, that can be added to stainless steel to ensure resistance to air, water and many acids and alkali. Nickel.✓ (1) 2.2 2.2.1 A reason why copper is not a suitable material for the manufacturing of pipefittings. Copper is too soft/Copper is likely to bend.✓ (1) 2.2.2 The name of the alloy element that is used with copper to form durable brass pipefittings. Zinc.✓ (1) 2.2.3 THREE properties of brass. • Strength✓ • Ductility✓ • Wear resistance✓ • Hardness✓ • Conductivity✓ • Corrosion resistance✓ • Antimicrobial✓ (Any 3) (3) Copyright reserved Please turn over

Agricultural Technology 4 DBE/May/June 2024 SC/NSC – Marking Guidelines 2.3 THREE common uses of tin. • Tin is used as a coating on the surface of other metals to prevent corrosion.✓ • ‘Tin’ cans.✓ • Alloys of tin: Soft solder, pewter, bronze and phosphor bronze.✓ • Tin chloride is used as a penetrant in dyeing textiles and for increasing the weight of silk.✓ • Stannous fluoride is used in some toothpastes.✓ • Tin foil.✓ (Any 3) (3) 2.4 2.4.1 TWO important aspects that must be considered when choosing a specific adhesive for a repairing task. • Type of material to be joined.✓ • Conditions under which this joint will be used.✓ (2) 2.4.2 Discussion of heat resistance as a property of an adhesive. The adhesive itself should not distort✓, melt✓ or burn✓ when heated.✓ (Any 2) (2) 2.4.3 Explanation of the difference between duration of usability and duration of cohesion in adhesives. Duration of usability: Period of time during which the mixed adhesive remains usable before setting.✓ Duration of cohesion: The period of time that an adhesive will stick after having been applied.✓ (2) 2.5 2.5.1 FOUR characteristics of fibre glass which makes it a suitable material for the manufacturing of small boats. • Lightness.✓ • Watertight.✓ • Can be casted into any shape.✓ • Easy to colour.✓ • Colour fast.✓ • Can be sawn, drilled, and filled.✓ • Toughness.✓ • Easy repaired when break.✓ (Any 4) (4) Copyright reserved Please turn over

Agricultural Technology 5 DBE/May/June 2024 SC/NSC – Marking Guidelines 2.5.2 FOUR precautionary measures that must be taken by the person working with fibreglass. • Catalyst and accelerator should always be stored separately.✓ • Remove all resin catalyst and accelerator from skin.✓ • Wear gloves if skin is sensitive.✓ • Use acetone in well-ventilated room.✓ • Handle resin casting carefully, they are brittle.✓ • Fibreglass matting has small pieces of fibre that can penetrate the skin.✓ • Do not breathe in glass fibre or get it in your eyes.✓ (Any 4) (4) 2.6 A few types of material used on farms. 2.6.1 Vesconite✓ (1) 2.6.2 Magazines for guns✓, Teflon tape✓, Teflon coated cooking pans✓, Teflon tape for sealing fittings✓, Car wash products✓, O-rings✓, Oil and water seals✓, Teflon Taps✓, fittings✓, non- return valves✓ and Flanges✓, Pipe saddles.✓ (Any 2) (2) 2.6.3 Bronze is an alloy consisting primarily of copper, usually with tin✓ as the main additive. It is hard and tough.✓ (2) 2.7 2.7.1 Name of part A. Earth spike.✓ (1) 2.7.2 Identification of the device shown in the illustration that produces the electricity for the electric fence. Energiser.✓ (1) 2.7.3 Function of part B. Insulators are used to fasten electrified wire to fence posts without losing energy through the posts.✓ (1) 2.7.4 The material from which part B is manufactured. Ceramic,✓Plastic,✓PVC.✓ (Any 1) (1) [35] Copyright reserved Please turn over

Agricultural Technology 6 DBE/May/June 2024 SC/NSC – Marking Guidelines QUESTION 3: ENERGY 3.1 3.1.1 TWO instances where a small wind turbine can be useful on a farm. • Electrical water pump.✓ • Small home/caravan/ boat.✓ • Auxiliary power for security gate/CCTV/Lights.✓ • To charge batteries.✓ (Any 2) (2) 3.1.2 TWO disadvantages of wind turbines. • Insufficient wind in the area.✓ • Effectiveness of wind turbines.✓ • Noise pollution.✓ • Competition with other alternative energy sources.✓ • High initial cost.✓ (Any 2) (2) 3.1.3 The importance of a large wing area in relation to the generation of electrical energy. The larger the wing area of the blades,✓the more wind energy is harnessed to rotate the turbine.✓ (2) 3.1.4 The device installed in the head of the wind turbine to decrease torque and increase input shaft speed to the generator. Gearbox.✓ (1) 3.2 3.2.1 Identification of the type of alternative energy system. Photovoltaic/Solar energy✓ (1) 3.2.2 A suitable material for the coating on the panels and ONE property of this coating. Material: Shatterproof glass/Teflon/Silicon /Ceramic.✓ Property: Self-cleaning/ Lightweight/ Non-pollutant/ Anti-reflective/ improved efficiency.✓ (2) 3.2.3 A component that can be installed in the system to prevent overcharging of the batteries. Regulator/Charge controller.✓ (1) Copyright reserved Please turn over

Agricultural Technology 7 DBE/May/June 2024 SC/NSC – Marking Guidelines 3.3 Correct sequence of the geothermal power station. STEPS GENERATION SEQUENCE 1 Cold water is pumped into the borehole.✓ 2 Underground heat source heats up the water.✓ 3 Steam is transferred to a turbine & generator unit.✓ 4 Generated electrical energy is sent to the national grid.✓ 5 A condenser cools the steam and water is formed.✓ (5) 3.4 Description of the term “biofuel” and one example of such a fuel. Biofuel or bioorganic fuel is any plant or animal matter ✓that can be (3) combusted and used as a fuel. ✓ Methane gas, ✓ Methanol, ✓ Ethanol ✓ (Any 1) (1) [20] Copyright reserved Please turn over

Agricultural Technology 8 DBE/May/June 2024 SC/NSC – Marking Guidelines QUESTION 4: SKILLS AND CONSTRUCTION PROCESSES 4.1 4.1.1 Identification the part on the MIG welding aparatus that are used by the welding operator to activate the electrical charge to the workpiece. Trigger/switch on the MIG welding gun.✓ (1) 4.1.2 Description of the MIG welding process. • The MIG welding machine sends a current through the continuously fed positive wire to the welding area when the operator presses the trigger on the welding torch.✓ • The electric arc creates a short circuit between the wire and work-piece.✓ • The heat produced by the short circuit, melts the metal and allows them to mix.✓ • An inert shielding gas protects the welding area from oxygen contamination.✓ • Once the heat is removed, the metal begins to cool and solidify, and forms a piece of fused metal.✓ (5) 4.1.3 The composition of the MIG welding shielding gas. Argon,✓Helium,✓ CO2✓ (3) 4.1.4 FOUR problems that will prevent the welding wire not to feed through the torch gun when welding. • Blocked/defective contact tip.✓ • Loose/broken wire drive/rollers.✓ • Entangled wire in delivery pipe.✓ • Broken torch trigger switch.✓ • Rusted wire jammed on spool.✓ • Wrong size of wire/rollers.✓ • Damaged/blocked/coiled torch liner.✓ (Any 4) (4) 4.1.5 Identification of the welding defect. Defect: Undercutting.✓ Causes: Speed too fast,✓current too high,✓ poor technique.✓ (Any 3) (3) Copyright reserved Please turn over

Agricultural Technology 9 DBE/May/June 2024 SC/NSC – Marking Guidelines 4.2 Description of the procedure that must be followed in preparing galvanized metal for the welding process. • This galvanized coating makes it difficult to be welded and must be removed prior to welding.✓ • Wear a gas mask to protect the welding operator against poisonous gas fumes.✓ (2) 4.3 Labelled drawing of a horizontal square butt weld. Marks will be allocated for the following: Design 1 Angle of electrode 1 Direction of travel 1 Neatness 1 Labelling 1 Work piece Direction of travel Welding electrode (5) 4.4 THREE pipe welding positions. • Horizontal fixed position.✓ • Horizontal movable position.✓ • Vertical position.✓ (3) Copyright reserved Please turn over

Agricultural Technology 10 DBE/May/June 2024 SC/NSC – Marking Guidelines 4.5 4.5.1 Metals that should not be cut with the apparatus with a motivation. • Aluminium, copper.✓ Their high thermal conductivity causes them to melt away too quick, leaving a very porous cut.✓ OR • Stainless steel.✓– The presence of nickel and molybdenum makes it difficult because it creates an oxide film on the base metal.✓ (2) 4.5.2 When the torch is moved too fast when cutting a thick metal plate. • The molten puddle will stick to one another.✓ • The flame will not penetrate the plate.✓ • The cut will form slag.✓ (3) 4.6.1 The material that is used for manufacturing the plasma cutter combustion cap. • Porcelain✓ • Ceramic✓ (Any 1) (1) 4.6.2 THREE properties of the Porcelain/Ceramic. Heat resistant.✓ Durable.✓ Does not conduct electricity.✓ (3) [35] Copyright reserved Please turn over

Agricultural Technology 11 DBE/May/June 2024 SC/NSC – Marking Guidelines QUESTION 5: TOOLS, IMPLEMENTS AND EQUIPMENT 5.1 5.1.1 Identification of the power source of each of the mowers. • A- Electric.✓ • B- Petrol.✓ (2) 5.1.2 TWO maintenance tasks to be performed on mower B. • Safety screens/equipment should be inspected and in place.✓ • Check oil and fuel level.✓ • Replace broken/worn parts.✓ • Service according to manufactures specification.✓ • Clean the mower after each use.✓ (Any 2) (2) 5.1.3 TWO safety tips when working with lawn mowers. • Read and understand the operator’s manual and become familiar with the machine.✓ • Remove all debris from lawns before mowing.✓ • Use recommended PPE including close-fitting clothing when operating a lawn mower.✓ • Disengage the blade before starting.✓ • Keep all guards and safety shields in place.✓ • Never disengage any safety interlock switches.✓ • Never refuel the mower when the engine is hot or running.✓ • Store gasoline in an approved container with proper label.✓ • Turn off the motor before cleaning the area under the deck.✓ • Disconnect the spark or electric plug before trouble- shooting or repairing the mower.✓ • Perform routine maintenance according to the schedule recommended by the manufacturer.✓ • Keep a running mower away from bystanders and pets.✓ (Any 2) (2) Copyright reserved Please turn over

Agricultural Technology 12 DBE/May/June 2024 SC/NSC – Marking Guidelines 5.2 5.2.1 Identification of the safety hazards. A No safety screen in place.✓ B Damaged safety screen.✓ C Worker climbing over PTO-driving shaft/Bystanders that can be injured.✓ D Hands near moving parts/No safety screens.✓ (4) 5.2.2 When setting up a hammer mill, it needs to be on a level surface. Motivation for the statement. Yes✓ • Ensures the mass of moving parts are spread equally over bearings. ✓ • Cyclone hang level on the blower pipe. ✓ • Looks neat. ✓ • Minimize vibration. ✓ (Any 2 + 1) (3) 5.2.3 A PTO-driving shaft can reach a rotational speed of up to 2800 r/min (revolutions per minute). Calculation on revolutions per second. 2800 r/min ÷ 60 minutes✓ = 46.66✓ r/sec✓ (revolutions per (3) second). 5.3 Matching of the correct use of parts. 5.3.1 D.✓ 5.3.2 E.✓ 5.3.3 B.✓ 5.3.4 C.✓ 5.3.5 A.✓ (5) Copyright reserved Please turn over

Agricultural Technology 13 DBE/May/June 2024 SC/NSC – Marking Guidelines 5.4 5.4.1 A table with TWO advantages and TWO disadvantages of each type of baler. BALE ADVANTAGES: DISADVANTAGES: TYPE: Round • Roofed storage not • Not easily transported.✓ bales necessary.✓ • Must be handled • One-man mechanically.✓ operation.✓ • No automatic packing • Packing of bales machines.✓ less time • Relatively vast storage consuming.✓ area. ✓ (Any 2) • Easily roll down steep hills.✓ (Any 2) Rectangular • Bales stored • Must be stored under bales easily.✓ roof.✓ • Easier to pack on • Higher labour needs.✓ the trailer.✓ • Time consuming during • Storage space stacking of bales.✓ optimally utilized.✓ (Any 2) • Easily handled by hand.✓ (Any 2) (8) 5.4.2 TWO methods that can be used to load large bales onto a trailer. • Front end bale loader/Fork loader.✓ • Mechanical devices/Conveyer belt.✓ • Loader on the three point mechanism.✓ (2) 5.4.3 TWO safety measures need to be followed when bales are transported to the shed. • Only one person on the tractor. ✓ • No one allowed to sit on bales during transport. ✓ • Do not over speed. ✓ • Use a lower gear when going downhill, since the tractor brakes alone may not be able to stop the load. ✓ • When going uphill, also use a low gear, so that you will not have to hold the load with the tractor brakes while changing gears up the slope. ✓ • Do not attempt to change gears during descend, begin descend in a low gear. ✓ • Never operate a hay trailer on the highway that is not equipped with brakes. ✓ • Hand signals should be used and understood by both the operator and those assisting. ✓ (Any 2) (2) Copyright reserved Please turn over

Agricultural Technology 14 DBE/May/June 2024 SC/NSC – Marking Guidelines 5.1 5.5.1 The part that enables the lifting arms to start moving. Control lever. ✓ (1) 5.5.2 Name of the part labelled as A. Automatic depth control mechanism/ sensitivity element spring. ✓ (1) 5.5.3 Explanation of what will happen to the plough if the top-link is not connected and the tractor starts moving forward. The back of the plough will tend to lift up out of the soil✓ or the front of the tractor will tend to lift up.✓ (2) 5.6 Identification of the type of hydraulic cylinder used in the pictures. 5.6.1 Single action hydraulic cylinder✓ 5.6.2 Double action hydraulic cylinder ✓ 5.6.3 Single action hydraulic cylinder ✓ (3) [40] Copyright reserved Please turn over

Agricultural Technology 15 DBE/May/June 2024 SC/NSC – Marking Guidelines QUESTION 6: WATER MANAGEMENT 6.1 6.1.1 TWO advantages of using this irrigation system. • Time saving. ✓ • Can irrigate large lands. ✓ • One-man operation. ✓ (Any 2) (2) 6.1.2 TWO communication devices that a farmer can use to effectively control the system. • Cell phone✓ • Tablet✓ • Computer✓ • Laptop✓ (Any 2) (2) 6.1.3 TWO tips a farmer must consider before choosing the type of fertiliser to apply through a centre pivot irrigation system. • Fertiliser with a high acid content must be avoided. ✓ • Fertiliser with large particles must be avoided. ✓ (2) 6.2 6.2.1 When a farmer would prefer pump A over pump B. • No electrical power required to operate the pump.✓ • Can pump larger volumes of water.✓ • It can be moved easily/mobile.✓ • No electrical installation needed.✓ • No shocking hazards.✓ (Any 3) (3) 6.2.2 THREE factors to consider when choosing a new pump for an irrigation field. • Type of pump.✓ • Estimated flow (ℓ/min).✓ • Pressure requirements.✓ • Research available for pump models.✓ • Capacity of the pump.✓ • Durability of the pump.✓ • Availability of electricity.✓ (Any 3) (3) Copyright reserved Please turn over

Agricultural Technology 16 DBE/May/June 2024 SC/NSC – Marking Guidelines 6.2.3 THREE reasons why PVC pipes are preferred over steel pipes to supply water to an irrigation system. • PVC does not rust.✓ • PVC is lightweight.✓ • PVC is flexible.✓ • Easy to join.✓ • Available in long lengths.✓ • Easy to work with.✓ • Cheaper.✓ (Any 3) (3) 6.2.4 Calculation of the time it will take to empty the water source. Formula: Flow rate = Volume of water Time Time = Volume of water✓ Flow rate = 72 000 ✓ 120 = 600 ✓ ℓ/min.✓ (4) 6.3 TWO types of drainage system that can be used to remove excess water around the buildings of a dairy farm. • Channel drain.✓ • Slope drain.✓ • Drainage ditch.✓ (Any 2) (2) 6.4 TWO different water purification methods that can be used to purify brackish water. • Distillation.✓ • Reverse osmosis.✓ (Any 2) (2) 6.5 6.5.1 Explanation of the construction and working of the distribution field that is connected to the septic tank. • A system that consist of a narrow trench, partially filled with a bed of washed gravel or crushed stone, into which perforated or open joint pipe is placed.✓ • The discharge from the septic tank is distributed through these pipes into the trench and surrounding soil.✓ • The subsurface absorption field must be properly sized and constructed.✓ (3) Copyright reserved Please turn over

Agricultural Technology 17 DBE/May/June 2024 SC/NSC – Marking Guidelines 6.5.2 Why a distribution field should NOT be built near drinking water installations or boreholes. • Septic tank water is contaminated with harmful chemicals.✓ • It will contaminate the water with deadly pathogens/bacteria.✓ (2) 6.6 TWO instances where V.R.T (Variable Rate Technology) can be used in precision farming. • Precision planting.✓ • Application of Fertilizers/Lime.✓ • Water application Irrigation systems.✓ • Application of Pesticides/Herbicides.✓ (Any 2) (2) [30] TOTAL SECTION B: 160 GRAND TOTAL: 200 Copyright reserved