An art teacher wants to hold drawing lessons outdoors so that students can sketch landscapes from observation. The school has only a few studio easels and t...

(a) Four functional points [4 marks]

1. Compact folded size for carrying — The easel must fold small enough for a student to carry in one hand or slung over a shoulder alongside other art supplies. A folded length no greater than 600 mm (the height of a typical school bag) and a collapsed thickness under 50 mm makes it practical for a class of 30 students to transport simultaneously. [1]
2. Board support ledge or lip — An A2 drawing board (420 mm x 594 mm) must rest securely on the easel without sliding off the bottom. A ledge or lip (at least 15 mm deep) at the base of the support area catches the bottom edge of the board and prevents it from sliding down under the weight of paper and drawing pressure. [1]
3. Adjustable angle — Different drawing and painting techniques require different board angles: near-vertical (70-80 degrees) for pencil and charcoal drawing, and more inclined (45-60 degrees) for watercolour work where washes must flow downward in a controlled way. An adjustable prop or telescopic leg that locks at multiple positions provides this flexibility. [1]
4. Stability on uneven ground — School playing fields and outdoor spaces have uneven grass, slopes, and soft ground. The easel legs must spread wide enough to create a stable triangular or rectangular footprint, and the feet should have rubber tips or pointed ends that grip soft ground without sinking excessively. [1]

(b) Two folding mechanisms [4 marks]

Mechanism 1 — Pivot and wing-nut lock: The rear leg is connected to the main frame by a bolt that acts as a pivot point. The leg swings inward to fold flat against the frame. A wing nut on the bolt can be hand-tightened to lock the leg at any angle. The annotated sketch shows the leg in the open (working) position and the folded (carrying) position, with the wing nut accessible for one-handed adjustment. This mechanism is simple, reliable, and uses standard hardware. [2]

Mechanism 2 — Telescopic sliding tube with spring pin: Aluminium tubes of two diameters are nested, with the inner tube sliding inside the outer tube. A spring-loaded pin (a ball detent or a plunger pin) snaps into holes drilled at intervals in the inner tube, locking it at different extended lengths. Pushing the pin releases the lock, and the inner tube slides in to collapse the leg. The annotated sketch shows the extended and collapsed positions and the spring pin detail. This mechanism allows continuous height adjustment. [2]

(c) Three design ideas [12 marks]

Idea 1 — Traditional tripod with telescopic aluminium legs: Three aluminium tube legs (25 mm diameter) are connected at the top by a central bracket. Each leg telescopes to adjust height, locking with spring-loaded pins. A canvas or plywood board support strip is hinged to the front of the bracket, with a lip ledge at the bottom and an adjustable clamp at the top to hold the board. A fabric carrying strap is attached. The tripod base provides good stability on uneven ground, and the three-legged design can be levelled even on slopes. [4]

Idea 2 — Two-legged easel with shoulder strap: Only two legs support the board, with the student's body providing the third support point via a strap over one shoulder. This halves the weight and folded size but relies on the student standing still, making it unsuitable for extended painting sessions and uncomfortable after prolonged use. [4]

Idea 3 — Flat-pack frame with integrated hinges: A single plywood plank unfolds via two piano hinges into an A-frame structure. The board rests against the front panel, which has a routed ledge. When folded, the entire easel is a flat plank approximately 600 mm x 100 mm x 20 mm. This design is very compact but the plywood construction is heavier than aluminium tube, and the fixed hinge angles limit the board angle adjustment. [4]

(d) Evaluation and justification [8 marks]

Idea 1 (Tripod) — Strengths: most stable on uneven ground; telescopic legs allow both height and angle adjustment; lightweight aluminium construction; freestanding so the student can step back to assess work. Weaknesses: three telescopic legs mean more moving parts.

Idea 2 (Two-legged) — Strengths: lightest option; very compact when folded. Weaknesses: relies on the student standing still; not freestanding; uncomfortable strap during long sessions.

Idea 3 (Flat-pack) — Strengths: extremely compact; no loose parts. Weaknesses: heavier than aluminium; limited angle adjustment; plywood exposed to rain may warp over time.

Chosen idea: Idea 1. The tripod design offers the best stability on the uneven ground of a school field, fully adjustable height and angle via telescopic legs, and lightweight aluminium construction. Being freestanding, it allows the student to stand, sit, or step back without the easel moving. The carrying strap and folding design make it practical for a class of students to transport together. [8]

(e) Full solution — construction details [12 marks]

The solution is drawn in isometric projection with a detail of the telescopic joint and a diagram of the folded position.

• Legs: Three 25 mm outer-diameter aluminium tubes, each with a 20 mm inner tube that slides inside. Extended height range: 1000-1500 mm. Each leg locks at four height positions using a spring-loaded ball detent that engages with 5 mm holes drilled in the inner tube at 120 mm intervals.
• Central bracket: A machined aluminium block (50 mm x 50 mm x 30 mm) with three drilled and tapped holes at 120 degrees to receive the top of each leg tube. Each leg is secured with a wing-nut pivot bolt (M6) that allows the leg to swing inward for folding.
• Board support: A 6 mm marine plywood strip (500 mm x 50 mm) is hinged to the front of the central bracket. The strip has a 15 mm lip at the bottom to support the drawing board and a spring clip at the top to hold the board against the strip.
• Leg spread: When fully extended, the three legs spread to a base diameter of approximately 800 mm, giving a stable triangular footprint.
• Feet: Rubber caps with pointed steel tips (removable) for soft ground.
• Carrying strap: 25 mm nylon webbing with a shoulder pad, attached to the central bracket.
• Folded dimensions: Approximately 550 mm long x 80 mm diameter bundle.

(f) Materials [4 marks]

1. Aluminium tube (25 mm diameter, 1.5 mm wall) for the legs. Aluminium is approximately one-third the weight of steel, making the easel light enough for a student to carry comfortably. It does not rust when exposed to rain (aluminium forms a protective oxide layer), and the tube profile provides excellent strength-to-weight ratio. Standard aluminium tube is widely available and can be cut with a hacksaw. [2]
2. Marine plywood (6 mm) for the board support ledge. Marine plywood is bonded with waterproof (WBP) adhesive, so it will not delaminate when used outdoors in damp conditions. It is stiff enough to support an A2 drawing board without flexing, and its smooth surface will not snag paper. It can be easily shaped with a coping saw and sanded smooth. [2]

(g) Manufacturing the board support ledge [6 marks]

1. Mark out: Mark the ledge shape (500 mm x 50 mm, with a 15 mm upstand lip at the front edge) on 6 mm marine plywood using a pencil, steel rule, and try square. [1]
2. Cut main shape: Cut the ledge to length using a tenon saw, keeping to the waste side of the marked line. [1]
3. Cut upstand lip: Cut the upstand lip profile using a coping saw, following the marked outline. The lip prevents the drawing board from sliding off the bottom of the support. [1]
4. Smooth edges: Smooth all cut edges using a file and then glasspaper, working through grades from 80-grit to 180-grit. Round all corners slightly for safety. [1]
5. Drill fixing holes: Drill two 6 mm clearance holes for the bolts that will attach the ledge to the central bracket, using a pillar drill with a 6 mm twist bit. [1]
6. Apply finish: Apply two coats of exterior-grade polyurethane varnish to seal the wood against moisture. Allow the first coat to dry fully before applying the second. The varnish creates a hard, waterproof surface that protects the plywood from rain and dew during outdoor lessons. [1]