Presentation: Designing Sustainable Packaging

Slide 1 of 7 · Settling starter · Design Technology · Year 10

5 minutes

Designing sustainable packaging for 6 Welsh cakes

The Year 10 enterprise group is selling boxes of 6 Welsh cakes at the school fair. The pack must protect the cakes, survive a greasy afternoon, be recyclable in an ordinary Welsh kerbside collection, and cost as little as possible. You are designing it.

While the register is called: write your name, class and date on your worksheet, then read the whole datasheet, including the drawbacks column and the net rules at the bottom.

Starter question: Which of the 6 materials is the cheapest per square metre, and which one is not accepted in any Welsh kerbside collection?

DCF: Producing → Creating digital content Ruler, pencil and calculator; computers optional

Supply teacher script (no subject knowledge needed)

Hand out: one worksheet per pupil and one stimulus sheet (Packaging material datasheet) per pupil or between two. Pupils need a ruler, a pencil and a calculator. Parts A to D are paper only; Part E is a 10-minute digital extension if machines are available, otherwise it is written on paper.

Say aloud: “Name, class and date at the top of your worksheet. While I take the register, read the datasheet right through: the drawbacks column and the net rules at the bottom matter most. Answer the starter question in rough.”

Starter answer: cheapest is F, greaseproof glassine paper at £0.30 per m² (A, recycled cartonboard at £0.42, is the cheapest board). Not accepted kerbside at all is E, PLA bioplastic film.

Slide 2 of 7 · Today’s brief and key words · Design Technology · Year 10

3 minutes

Your brief: sizes, a net that closes, honest materials, real costs

You will work out the internal sizes (Part A), draw the net at 1:2 scale and prove it closes (Part B), choose materials and name what each costs you (Part C), work out cost and mass for 1 box and for 120 (Part D), and write the on-pack message (Part E).

Net

The flat shape that folds into the box: 4 side faces in a strip, a top panel, a bottom panel, tuck flaps and 1 glue tab.

Perimeter

2 × (L + W). The strip of 4 side faces must be exactly this long or the box will not close.

gsm

Grams per square metre. Mass of a blank = area in m² × gsm. 1 m² = 1,000,000 mm².

Mixed-material pack

Card plus a plastic window or laminate. Sorting lines commonly reject the whole box.

DCF: Producing → Creating digital content Every material has a real drawback; “none” is not an answer

Slide 3 of 7 · Part A: how big does it need to be? · Design Technology · Year 10

7 minutes

Part A: arrange the 6 cakes, then work out L, W and H

Each cake is 60 mm across and 15 mm thick. Decide how the 6 cakes sit in the box, work out the space they take up, add a little clearance, then calculate the internal volume in mm³ and cm³.

Question	Model answer
How I am arranging the 6 cakes	2 stacks of 3, lying flat, side by side along the length. A single stack of 6 would be 90 mm tall and would topple.
Space the cakes take up	2 circles of 60 mm side by side = 120 mm long, 60 mm wide, 3 × 15 = 45 mm high: 120 × 60 × 45 mm.

Part A on your worksheet · 7 minutes Clearance of about 5 mm: enough to get the cakes out, not enough to let them slide

Slide 4 of 7 · Part B: draw the net and prove it closes · Design Technology · Year 10

14 minutes

Part B: draw the net at 1:2 scale, then do the closure check

At 1:2 scale, 125 mm on the box is 62.5 mm on your drawing. You need 4 side faces in a strip, a top panel, a bottom panel, tuck flaps of about 25 mm on the lid and 1 glue tab of 12 to 15 mm. Label every dimension in real millimetres. Fold lines dashed, cut lines solid.

Closure check	Model answer
Perimeter: 2 × (L + W)	2 × (125 + 65) = 2 × 190 = 380 mm
My 4 side faces added together	125 + 65 + 125 + 65 = 380 mm. They match, so the strip wraps round exactly once.

Part B on your worksheet · 14 minutes Do the closure check before you colour anything in

Supply teacher script (no subject knowledge needed)

Say aloud: “Draw your net in pencil in the frame, at half size. The first 2 rows of the closure check are on the board. If your 4 side faces do not add up to your perimeter, your box will not close, so check that before you draw anything else. The net is the part your class teacher will mark.”

Quick check: the lid is 125 × 65 mm and the opening is L × W = 125 × 65 mm, so it covers it exactly; the 25 mm tuck flap folds inside the 50 mm deep front face. Overall flat size: width 380 + 15 glue tab = 395 mm; height 25 + 65 + 50 + 65 + 25 = 230 mm. An A3 sheet is 420 × 297 mm, so it fits with 25 mm and 67 mm to spare.

Walk the room: the one mistake worth stopping the class for is 4 side faces that do not add up to the perimeter. Also look for a top panel smaller than L × W, flaps missing, and dimensions written at drawing size instead of real millimetres.

Slide 5 of 7 · Parts C and D: materials, cost and mass · Design Technology · Year 10

16 minutes

Part C: choose materials honestly. Part D: cost and mass for 120 boxes

Part C (9 min): use letters A to F from the datasheet. Every row needs a real drawback, not “none”. Part D (7 min): add up every panel, flap and tab in your own net, convert to m², then multiply by your board’s gsm and cost.

Part of the pack	Material	Why	What I am giving up
The box itself	A, recycled cartonboard, 350 gsm	Collected kerbside almost everywhere in Wales, cheapest board at £0.42/m².	Grey-brown base makes printed colours dull; needs 350 gsm not 300 gsm, so heavier.
Grease barrier	F, glassine paper liner, 40 gsm	Butter marks bare card within a day. Paper inside paper keeps the pack single-material.	Only good for about 3 days, no strength, and a second part to cut and fold.

Parts C and D on your worksheet · 16 minutes Mass = area in m² × gsm · 1 m² = 1,000,000 mm²

Supply teacher script (no subject knowledge needed)

Say aloud: “Two rows of the materials table are on the board as a model. Fill in the window row and the print and finish row yourselves, with a real drawback in every row. Then Part D: add up every panel, flap and tab in your own net, divide by a million to get square metres, and multiply by the gsm and the cost of the board you chose.”

Quick check, Part C: Window: none, because D (rPET film) makes the pack mixed material and sorting lines reject the whole box, and E (PLA film) is not collected in Wales at all; the drawback is that customers cannot see the cakes, which loses sales, so keep 1 open box on the stall. Print and finish: water-based inks, no laminate, PVA-type glue; a gloss laminate would cancel out every other decision; drawback is slightly less punchy colours and a box that marks in the rain.

Quick check, Part D (model net): side strip 380 × 50 = 19,000; lid 8,125; base 8,125; 2 tuck flaps 3,125 each = 6,250; glue tab 15 × 50 = 750. Total 42,250 mm² = 0.04225 m². Mass 0.04225 × 350 = 14.8 g, plus liner 180 × 120 mm = 0.0216 m² × 40 = 0.9 g, so 15.7 g per pack. Cost 0.04225 × £0.42 = 1.8 p, plus 0.6 p liner = 2.4 p per pack; 120 boxes = £2.88. Total card 120 × 15.7 g = about 1.9 kg. The catch: only 1 net fits on an A3 sheet, so a whole sheet per box is really 5.2 p and 27% waste. Pupils’ own figures will differ with their own net; check the method, not the exact number.

Slide 6 of 7 · Part E and self check · Design Technology · Year 10

3 minutes

Part E: the on-pack message, then check your own work

Write what will actually be printed on the base of the box. It must tell a customer in Wales what to do with each part of the pack, and it must be true of the materials you chose. Then tick the success criteria you have met and correct 1 thing.

My internal sizes come from the actual size of six cakes, with clearance, and I can show the arrangement.
My net closes: the four side faces add up to the perimeter, and the top panel matches the opening.
My net fits on one A3 sheet, and every fold, cut, flap and tab is labelled with a real dimension.
Every material choice names an honest drawback, and I do not claim something is recyclable when the datasheet says otherwise.
My cost and mass figures are worked out from my own net area and my own board weight, and the on-pack message is true of the materials I chose.

Part E on your worksheet · 3 minutes Finished early? Redesign for 4 cakes, or answer the gloss laminate request

Supply teacher script (no subject knowledge needed)

Say aloud: “Write the 3 lines that go on the base of the box: what to do with each part, and only claims that are true of your materials. If you have a computer you may redraw your net or lay out the printed face and save it with your name and the date in the file name. Then tick the success criteria and fix 1 thing.”

Quick check: a model message reads: “CARD BOX: recycle with paper and card. PAPER LINER: recycle with paper, or add to your home compost. No plastic film. No laminate. No sticky labels. Printed with water-based inks on 100% recycled board. Best within 3 days. Contains wheat (gluten), milk and egg.” A pupil who chose the rPET window would have to print “check local recycling” instead.

Extension answers: 4 cakes at the same height means 1 stack of 3 plus 1, so the arrangement and length change and the strip shortens; the saving is the difference in net area times 120. To the gloss laminate request: it looks premium and wipes clean, but it makes the card unrecyclable in most kerbside collections, so 1 decorative choice cancels out the whole material choice. Only 1 of the 395 × 230 mm nets fits an A3 sheet, so 27% of every sheet is waste; rotating the net or buying board on a reel reduces it.

Slide 7 of 7 · Plenary review · Design Technology · Year 10

2 minutes

Quick-check answers before handing in

Swap with a partner and check their closure sum. Then check the 3 answers below.

Question	Correct answer
How long must the strip of 4 side faces be?	Exactly the perimeter, 2 × (L + W); for a 125 × 65 mm box that is 380 mm.
What does adding an rPET window do to the recycling of the box?	It becomes a mixed-material pack; sorting lines commonly reject the whole box.
How do you work out the mass of 1 blank?	Area in m² × gsm; the model net is 0.04225 × 350 = 14.8 g.

Check your name and class are on your worksheet Leave datasheets neat on the desk