| Date | November 2021 | Marks available | 3 | Reference code | 21N.2.SL.TZ0.1 |
| Level | SL | Paper | 2 | Time zone | no time zone |
| Command term | Suggest | Question number | 1 | Adapted from | N/A |
Question
Forceps are tools used for grasping or holding objects. Most forceps have mechanisms consisting of multiple parts, see Figure 1.
Some designers have developed alternative mechanisms for forceps that rely on the elasticity of the material for the transfer of force, movement or energy. These are often produced as one part.
“Oriceps” are forceps inspired by origami (the Japanese art of paper folding), see Figure 2 and Figure 3.
Figure 1: AfroBrazilian, 2012. Liston Bone Cutting Forecep curved 01. [image online] Available at:
https://commons.wikimedia.org/wiki/File:Liston_Bone_Cutting_Forcep_curved_01.jpg. Attribution-ShareAlike
3.0 Unported (CC BY-SA 3.0) https://creativecommons.org/licenses/by-sa/3.0/deed.en
[Accessed 10 September 2020].
Figure 2: BYU_CMR, 2018. Oricepts: Origami Inspired Foreceps. [image online]
Available at: https://www.thingiverse.com/thing:2988740 [Accessed 10 September 2020].
Figure 3: BYU_CMR, 2018. Oricepts: Origami Inspired Foreceps. [image online]
Available at: https://www.thingiverse.com/thing:2988740 [Accessed 10 September 2020].
Designed by George Nelson in 1958, the Nelson Swag Leg Desk is named after “swaging”, a manufacturing process that allowed the legs to be curved easily. The lightweight desk features walnut sides, four coloured hardwood dividers, laminate surface and legs shaped from chrome steel tubes, see Figure 5.
The desk is designed to be flat-packed and assembled by the consumer.
Figure 5: Nelson Swag Leg Desk image provided by Herman Miller.
Define elasticity.
Figure 4 shows an example of a stress / strain graph.
Describe what happens when the stress on a material causes it to exceed its yield point.
Describe how biomechanical data would have been used in the development of the forceps in Figure 1.
Outline one way how products that are produced as a single part can reduce manufacturing costs.
Outline how design for disassembly can help extend the lifespan of products with multiple parts.
Explain how finite element analysis (FEA) can be used to test products with multiple parts.
State one possible joining method used to attach the legs to the other parts of the desk.
Outline the percentile range used to calculate the reach from the front of the desk to the coloured dividers.
Outline one reason why the Nelson Swag Leg Desk achieved classic design status.
Suggest one reason why the depletion of hardwood reserves may have political implications.
Markscheme
The ability of a material to return to its original shape (after being deformed);
Award [1] for defining the term elasticity.
(Answer in brackets not required for the mark.)
Do not accept the words ‘stretch’ or ‘pull’ without reference to returning to its original shape.
The material goes from being elastic to plastic/undergoes plastic deformation;
Which means it will not be able to return to its original shape/deforms permanently;
Award [1] for each part of a description of what happens when the stress on a material causes it to exceed its yield point up to [2 max].
Do not accept ‘break’.
Biomechanical data measures mechanics/forces of the user (living organisms);
To determine the strength/effort required to grip/squeeze/compress the forceps;
Award [1] for each part of a description of how biomechanical data would have been used in the development of the forceps up to [2 max].
Design for assembly;
Additional workers/machines are not required to assemble the parts;
Design for manufacturing;
No assembly required resulting in higher production rate/less energy consumed;
Design for process;
Optimisation of a single process (such as injection moulding/die casting);
Design for materials;
Optimize economies of scale;
Award [1] for identifying how products that are produced as a single part can reduce manufacturing costs [1] for a brief explanation up to [2 max].
Do not award marks between clusters.
Design for disassembly allows products to be taken apart;
Which allows for cleaning/repair/replacing/maintenance of parts;
Award [1] for identifying how design for Disassembly can help extend the life span of products with multiple parts and [1] for a brief explanation up to [2 max].
Finite Element Analysis (FEA) can test the strength/load of a joining method/technique (using CAD);
When under stress/force;
In order to make modifications/improvements;
Award [1] for identifying how Finite Element Analysis (FEA) can be used to test products with multiple parts and [1] for each distinct explanation up to [3 max].
(Answer in brackets not required for the mark.)
Fasteners/knock-down fittings/nuts and bolts/screws;
Award [1] for stating a possible joining method used to attach the legs to the other parts of the desk up to [1 max].
Do not accept ‘nails’.
5th percentile;
So that 95% of the majority of the population can reach the dividers/to cater for the shortest reach;
Award [1] for identifying the percentile range used to calculate the reach from the front of the desk to the coloured dividers and [1] for a brief explanation up to [2 max].
Mass production;
Allows more consumers to own the product/makes it more affordable/meets demand;
Defies obsolescence;
By transcending its function;
Award [1] for identifying one reason how the Nelson Swag Leg Desk achieved classic design status and [1] for a brief explanation up to [2 max].
Social impact;
Deforestation/loss of habitat/human displacement;
Causing local unrest/people to migrate/unemployment/negative economic impact;
Environmental impact/reduction of CO2 absorption/renewability;
Hardwoods can only be replaced over a long period;
Affecting a country’s obligation to global sustainability agreements/targets;
Biodiversity;
Forests are home to flora/wildlife populations that are under threat;
That can wipe out species/affect the reputation of a country;
Award [1] for a distinct point for why the depletion of hardwood reserves may have political implications and [1] for each distinct explanation up to [3 max].
Do not award marks between clusters.
Examiners report
A straightforward definition with most students able to get the 1 mark.
Pretty straightforward for the second point with a number also able to achieve 2 marks for including something from the first point.
Some confusion with anthropometrics. Most only achieved 1 mark. Second point was harder as it had two parts to it.
Not well answered. Hardly anyone identified the strategy (dfa, dfm etc) which made it hard to achieve 2 marks. Some got one mark mostly from the first cluster. A more challenging question.
Straight forward with many able to achieve 2 marks.
A more challenging question. Some students got 1 or 2, but very few got 3 marks as many students didn’t relate their response back to the forceps.
Very straightforward. Most went for screws.
A fairly easy question that most candidates got wrong. Still some confusion about percentiles. Lots went for 5th-95th but others also went for 50th. Only a few had the 5th.
Not a difficult question but not well answered. Many candidates took the scattergun approach with classic design terminology like ubiquitous, recognisable, emotion/nostalgia etc. A few got one mark for mass production. Very few got 2 marks though.
Many candidates answered this with cross cluster responses. Some focused on governments/protests etc. Most candidates were able to achieve at least one mark, a number were able to achieve 2 but very few achieved 3. The second point of cluster two in the mark scheme and ‘deforestation’ seemed the most common answers. Very few mentioned biodiversity. This was not an easy question as it seemed to cross over into T8.
