2024 CCEA GCSE Technology and Design 8900 模拟试题及答案详解

CAD (computer-aided design) offers several advantages over hand-drawing: (1) drawings and designs can be produced and amended far more quickly than by hand; (2) files can be shared or emailed instantly to clients or manufacturers anywhere in the world; (3) 3D models can be rotated and tested/simulated on screen before any material is used, reducing costly prototyping errors; (4) CAD files can be sent directly to CAM (computer-aided manufacture) equipment for production; (5) designs are stored digitally, making them easy to retrieve, copy and reuse. Any three distinct, valid advantages are acceptable.

[1] mark for each valid, distinct advantage, up to [3]. Accept: quicker to produce/amend drawings; easy to share/transmit designs; enables 3D modelling/simulation before manufacture; direct link to CAM; easier storage/retrieval. Reject vague answers such as 'it is better' with no reason given.

(i) A black exclamation mark on a yellow triangle is the standard general warning/hazard symbol, indicating that caution is required in that area. (ii) When working at a pillar drill, appropriate PPE includes safety goggles (to protect the eyes from swarf) and/or an apron (to protect clothing and avoid loose clothing being caught). (iii) If long hair is not tied back, it can become caught in the rotating chuck or drill bit, pulling the person's head towards the machine and causing serious injury.

(i) [1] for 'general warning/caution/hazard'. (ii) [1] for any valid PPE item, e.g. safety goggles, apron. (iii) [1] for a valid hazard linked to entanglement/injury from rotating machinery. Maximum [3].

(i) Hardwoods come from broad-leaved, slow-growing trees; examples include mahogany, beech and oak. (ii) Softwoods come from coniferous, faster-growing trees; examples include pine and cedar. (iii) Manufactured boards are produced from wood particles, fibres or veneers bonded together with adhesive; examples include plywood, MDF, chipboard and veneered manufactured board.

[1] mark for each correct example, up to [3]. (i) Accept mahogany, beech, oak. (ii) Accept pine, cedar. (iii) Accept plywood, MDF, chipboard, veneered board. Reject examples placed in the wrong category (e.g. pine given as a hardwood).

Heat treatment processes change the internal structure of a metal to alter its working properties (such as hardness, toughness or ductility) without changing its shape. The main heat treatments studied are annealing (softening the metal to improve workability), normalising (relieving internal stresses and refining grain structure), hardening (increasing hardness, typically by rapid quenching) and tempering (reducing brittleness after hardening while retaining some hardness). Any three of these four processes is correct.

[1] mark for each correctly named heat treatment, up to [3]. Accept: annealing; normalising; hardening; tempering (any three).

(i) A try square (used on wood) or an engineer's square (used on metal) has one edge fixed at 90 degrees to the other, allowing an accurate right angle to be scribed onto a workpiece. (ii) A scriber (for metal) or marking knife (for wood) has a fine, hardened point that is drawn along a straightedge or rule to transfer a precise measurement as a scored line. (iii) A marking gauge has an adjustable fence and a sharp pin or wheel that is set to a fixed distance, allowing a line to be marked parallel to, and a set distance from, an edge.

[1] mark for each correct tool, up to [3]. (i) try square / engineer's square. (ii) scriber / marking knife. (iii) marking gauge. Accept alternative correct tool names that perform the described function.

(i) A butt joint is the simplest joint, formed by placing two square-cut pieces of timber together and gluing (or fixing) them, with no interlocking shape. (ii) A mitre joint is formed by cutting both pieces at a 45-degree angle so that when joined they form a 90-degree corner without any end grain being visible. (iii) A dowel joint uses one or more cylindrical wooden dowels glued into matching drilled holes in each piece, adding mechanical strength to the joint.

[1] mark for each correct joint name, up to [3]. (i) butt joint. (ii) mitre joint. (iii) dowel joint.

(i) A light dependent resistor (LDR) is a component whose resistance falls as the intensity of light falling on it increases, making it useful as a light sensor. (ii) A light-emitting diode (LED) only allows current to flow in one direction (it is polarised) and emits light when forward biased. (iii) An NPN transistor consists of three layers of semiconductor material (an n-type, p-type and n-type layer) and can act as an electrically operated switch, turning on when a small current/voltage is applied to its base.

[1] mark for each correct component, up to [3]. (i) LDR / light dependent resistor. (ii) LED / light-emitting diode. (iii) transistor / NPN transistor.

(i) Current is measured in amps (A), or milliamps (mA) for small currents. (ii) Voltage (potential difference) is measured in volts (V), or millivolts (mV). (iii) Resistance is measured in ohms (Ω), or kilohms (kΩ) and mega-ohms (MΩ) for larger values.

[1] mark for each correct unit, up to [3]. (i) amps/amperes (A). (ii) volts (V). (iii) ohms (Ω).

(i) A wheel turning about a fixed axle produces rotary motion (circular movement about a centre point). (ii) A sewing machine needle moving up and down along the same straight path repeatedly produces reciprocating motion. (iii) A pendulum swinging from side to side about a fixed point produces oscillating motion (movement back and forth through an arc).

[1] mark for each correct motion type, up to [3]. (i) rotary. (ii) reciprocating. (iii) oscillating.

In standard flowchart notation: (i) START/STOP points are shown using a rounded oval (terminator) shape. (ii) A DECISION, where the flow branches depending on a yes/no condition, is shown using a diamond shape. (iii) An OUTPUT (or general input/output) is shown using a parallelogram shape.

[1] mark for each correct shape, up to [3]. (i) rounded oval / terminator. (ii) diamond. (iii) parallelogram.

(a) The potential divider is formed by connecting the LDR and the variable resistor in series across the 6V battery; the variable resistor allows the switching sensitivity (light level) to be adjusted. (b) The junction (the point) between the LDR and the variable resistor is connected to the base of the NPN transistor, so the base voltage depends on the light level. (c) The LED (protected by its current-limiting resistor) is connected in series with the collector-emitter path of the transistor, and this series combination is connected across the battery, so current can only flow through the LED when the transistor switches on. (d) As it gets dark, the resistance of the LDR increases. Since the LDR and variable resistor form a potential divider, a larger share of the battery voltage now appears across the LDR, raising the voltage at the transistor's base above its switch-on voltage (approximately 0.6V); this turns the transistor on, allowing current to flow through the LED and light it.

(a) [1] LDR + [1] variable resistor identified as the potential divider pair. (b) [1] for base of the transistor. (c) [1] LED (with current-limiting resistor) + [1] transistor (collector-emitter), connected in series across the battery. (d) [1] for correctly stating LDR resistance increases in the dark AND linking this to a rising base voltage that switches the transistor on. Maximum [6].

Stage 1: START (terminator symbol) - the system begins. Stage 2: DECISION - 'Is the soil dry?' (diamond symbol), checking the input from the moisture sensor. Stage 3: if the answer is NO, a feedback loop returns the flow back to stage 2, so the system keeps checking. Stage 4: if the answer is YES, an OUTPUT (parallelogram symbol) turns the water pump ON. Stage 5: a WAIT symbol pauses the flow for the fixed watering time (for example, 2 minutes). Stage 6: an OUTPUT turns the water pump OFF, and a feedback loop then returns the flow back to stage 2 (the DECISION), so the whole process repeats indefinitely.

[1] mark for each correct stage in the correct sequence, up to [6]: START [1]; DECISION - soil dry? [1]; NO - feedback loop back to the decision [1]; YES - OUTPUT pump ON [1]; WAIT for fixed time [1]; OUTPUT pump OFF with feedback loop back to the decision [1]. Accept equivalent valid sequencing/wording that achieves the same repeating logic.

(a) Without an idler gear, a driver gear meshed directly with a driven gear causes the driven gear to rotate in the opposite direction to the driver. Adding a single idler gear between them reverses the direction a second time, so the final driven gear rotates in the SAME direction as the original driver gear. (b) The idler gear meshes with both the driver and the driven gear but is not itself connected to an output shaft that does useful work; mathematically, the idler's tooth count appears once in the numerator and once in the denominator of the overall ratio calculation and cancels out, so it changes only the direction of rotation, not the speed ratio. (c) Gear ratio = teeth on driven gear ÷ teeth on driver gear = 32 ÷ 16 = 2. This means the driver gear must turn twice for every one turn of the driven gear, so the driven gear (with more teeth) rotates more slowly than the driver gear (with fewer teeth).

(a) [1] idler reverses direction of rotation (twice) + [1] correct conclusion that driven gear rotates in the same direction as the driver. (b) [1] idler is not connected to an independent output/does no useful work of its own + [1] its tooth count cancels in the ratio calculation, only driver/driven teeth counts matter. (c) [1] driven gear rotates slower + [1] correct reason (more teeth on driven gear than driver gear / gear ratio of 2:1). Maximum [6]. Accept a correctly calculated gear ratio value (2 or 2:1) as valid support for part (c).

Component 1: the circuit begins with the pressure source (compressed air supply) symbol, providing air at the working pressure. Component 2: a 3/2 valve (three ports, two positions) is connected between the pressure source and the cylinder; it controls whether air flows to the cylinder or is exhausted. Component 3: the 3/2 valve is fitted with a roller-trip actuator, so that it is mechanically switched when an object (for example a cam or the vent-opening linkage) physically presses the roller. Component 4: the outlet port of the 3/2 valve is connected to the single acting cylinder (SAC), which extends when it receives pressurised air, pushing the vent open. Return mechanism: when the roller trip is released (no longer pressed), the internal spring inside the 3/2 valve returns it to its normal rest position, which cuts off the air supply to the cylinder and opens a path to exhaust; with no pressurised air holding it out, the SAC's own internal spring retracts the piston, closing the vent.

[1] pressure source identified as the starting component. [2] 3/2 valve correctly identified and positioned between source and cylinder (controls the air flow) - [1] for valve, [1] for correct position/function. [1] roller-trip actuator correctly identified as the method of operating the valve. [1] SAC correctly identified as the output/actuator connected to the valve's outlet. [1] correct explanation of the spring-return mechanism (valve spring resets, cylinder's own spring retracts the piston). Maximum [6].

(a) For an AND circuit, the two 3/2 valves are connected in series, one after the other, between the air supply and the cylinder: the pressure source feeds the inlet of the first push-button valve, the outlet of the first valve feeds the inlet of the second push-button valve, and the outlet of the second valve is connected to the single acting cylinder. (b) Air can only pass all the way through to the cylinder if BOTH valves are open (pressed) at once; if only one push-button is pressed, the other (unpressed) valve remains closed and blocks the air path, so the cylinder does not receive air and does not extend - this is the defining behaviour of an AND circuit. (c) To create an OR circuit instead, a shuttle valve is used in place of the series arrangement. A shuttle valve has two air inlets (each connected to one of the push-button 3/2 valves) and a single outlet connected to the cylinder; internally, a free-moving shuttle seals off whichever inlet is NOT pressurised, so air from either input alone can pass through to the cylinder, meaning pressing EITHER button is enough to extend the cylinder.

(a) [1] valves connected in series + [1] correct order (source to valve 1, valve 1 to valve 2) + [1] valve 2 outlet connected to the cylinder. (b) [1] for correctly stating the unpressed valve blocks the air path so the cylinder does not extend. (c) [1] shuttle valve named + [1] correct explanation that it passes air from whichever inlet is pressurised, sealing the other, giving OR logic. Maximum [6].

Formula: \( F = P \times A \), where \( A = \pi r^2 \).
Radius \( r = \frac{40}{2} = 20 \text{ mm} \).
Area: \( A = \pi \times 20^2 = \pi \times 400 = 1256.6 \text{ mm}^2 \).
Substitution: \( F = 0.3 \times 1256.6 \).
Calculation: \( F = 377.0 \text{ N} \).
Final answer: Force = 377 N (to 3 significant figures).

[1] mark for correctly finding the radius and calculating the cross-sectional area (\( A = \pi \times 20^2 = 1256.6 \text{ mm}^2 \)). [1] mark for correct substitution into \( F = P \times A \). [1] mark for the correct final answer with correct unit (377 N, accept 375-379 N depending on rounding of \( \pi \)). Error carried forward applies if the area is calculated incorrectly but the method is otherwise correct.

Formula, rearranged: \( A = \frac{F}{P} \).
Substitution: \( A = \frac{250}{0.4} \).
Calculation: \( A = 625 \text{ mm}^2 \).
Final answer: minimum cross-sectional area = 625 mm².

[1] mark for correctly rearranging \( F = P \times A \) to \( A = F \div P \). [1] mark for correct substitution (250 ÷ 0.4). [1] mark for the correct final answer with correct unit (625 mm²).

(i) Total resistance: \( R_t = R_1 + R_2 + R_3 = 220 + 330 + 470 = 1020 \ \Omega \).
(ii) Rearranging Ohm's law: \( I = \frac{V}{R_t} \).
Substitution: \( I = \frac{12}{1020} \).
Calculation: \( I = 0.01176 \text{ A} = 11.76 \text{ mA} \).
Final answer: total resistance = 1020 Ω; current ≈ 11.8 mA.

(i) [1] mark for the correct total resistance (1020 Ω). (ii) [1] mark for correctly rearranging Ohm's law and substituting values (\( I = 12 \div 1020 \)); [1] mark for the correct final answer with correct unit (11.8 mA, accept 11.7-11.8 mA / 0.0118 A). Error carried forward applies if part (i) is incorrect but the method in part (ii) is correct.

Radius: \( r = \frac{12}{2} = 6 \text{ mm} \).
Formula: \( A = \pi r^2 \).
Substitution: \( A = \pi \times 6^2 = \pi \times 36 \).
Calculation: \( A = 113.1 \text{ mm}^2 \).
Final answer: cross-sectional area = 113.1 mm².

[1] mark for correctly finding the radius (6 mm). [1] mark for correct substitution into \( A = \pi r^2 \). [1] mark for the correct final answer to 1 decimal place (113.1 mm²).

CAD/CAM systems and machinery (such as CNC routers or laser cutters) can be very expensive to purchase and set up. For a small business with limited capital, this initial investment cost may be difficult to justify or afford, especially if production volumes are low. In addition, staff need to be trained to use the software and equipment competently and safely, adding further cost and time before the investment starts to pay off.

[1] mark for identifying a valid disadvantage (e.g. high cost of equipment/software, need for staff training, risk of a systems fault halting production, or job losses/de-skilling of manual operators). [1]-[2] further marks for a developed explanation linking the disadvantage clearly to its impact on a small business. Maximum [3]. All other valid points given credit.

When a pillar drill bores into wood, metal or plastic, small fragments of material (swarf) are thrown off at speed by the rotating drill bit. Without eye protection, these fragments could strike and injure the operator's eyes, potentially causing permanent damage or loss of vision. Safety goggles form a physical barrier that protects the eyes from this flying debris, allowing the operator to work safely and observe the drilling process closely.

[1] mark for identifying that swarf/debris/particles are produced and thrown out during drilling. [1] mark for stating this could strike/injure the eyes. [1] mark for stating that goggles form a protective barrier preventing this injury. Maximum [3].

Both jigs and fixtures are devices used to hold a workpiece securely and consistently during manufacture, improving accuracy and repeatability when making multiple identical parts. The key difference is that a jig holds the workpiece AND guides the cutting tool during the operation - for example, a drilling jig holds a component in place and includes guide bushes that position the drill bit accurately, ensuring every hole is drilled in exactly the same place. A fixture, on the other hand, only holds and locates the workpiece securely; it does not guide the tool itself - for example, a welding fixture holds two components in the correct position relative to each other while an operator welds them, but does not guide the welding torch.

[1] mark for correctly stating that a jig guides the tool as well as holding the workpiece. [1] mark for correctly stating that a fixture only holds/locates the workpiece and does not guide the tool. [1] mark for a valid example of either a jig or a fixture in use. Maximum [3].

Stainless steel is an alloy of iron containing a significant proportion of chromium (typically at least 10.5%). The chromium reacts with oxygen in the air to form a thin, self-repairing protective oxide layer on the surface of the metal, which makes stainless steel highly resistant to corrosion and rusting, even when regularly exposed to water and food acids. Mild steel, in contrast, contains very little alloying element and corrodes (rusts) readily when exposed to moisture. Stainless steel's smooth, non-porous surface is also easy to clean and hygienic, which is an important property for kitchen sinks and worktops that come into contact with food.

[1] mark for identifying that stainless steel resists corrosion/rusting (unlike mild steel). [1] mark for a valid reason why (e.g. chromium content forms a protective oxide layer). [1] mark for a further valid property relevant to kitchen use (e.g. easy to clean/hygienic, aesthetically pleasing/does not need painting). Maximum [3].

A thermochromic pigment is a smart material that changes colour reversibly in response to a change in temperature; it changes back to its original colour when the temperature returns to its original level. When incorporated into a baby's bath thermometer, the pigment can be designed to display one colour (for example, a smiling face or a set colour) when the water is at a safe temperature, and to change to a different colour or pattern if the water becomes too hot. This gives parents/carers a quick, clear visual warning without needing to read a numerical scale, improving the safety of the product for checking bath water before a baby is placed in it.

[1] mark for correctly describing that thermochromic pigment changes colour reversibly with temperature. [1] mark for linking this to indicating whether the bath water is a safe/unsafe temperature. [1] mark for a further valid point (e.g. gives a clear, immediate visual warning; no need to read a numerical scale; improves safety for a baby). Maximum [3].

In a single acting cylinder (SAC), the outstroke occurs when compressed air is supplied to one side of the piston, pushing it out of the cylinder body to do useful work (for example, extending to move a load). The instroke occurs when the piston moves back into the cylinder body, returning it to its start position. Because a single acting cylinder only has one air connection, it cannot be pushed back in by air pressure; instead, it contains an internal return spring which pushes the piston back in once the air supply is removed and the cylinder is exhausted (vented) via the control valve.

[1] mark for correctly describing the outstroke (piston pushed out by compressed air, doing work). [1] mark for correctly describing the instroke (piston retracts/returns into the cylinder). [1] mark for correctly identifying that an internal spring (not air pressure) causes the return once the air supply is removed. Maximum [3].

A high-scoring answer addresses all four roles and explains how they interact.

The client is the person or organisation that commissions the product and pays for its development; in this case, the sports equipment company. The client sets the initial brief, including budget, timescale and broad requirements (for example, that the bottle must be lightweight, durable and suitable for outdoor sports use), and has final approval over design decisions and cost.

The user is the person who will actually use the finished product - in this case, someone taking part in outdoor sports. The user's needs must be researched and understood, including ergonomic factors (the bottle must be comfortable and easy to grip, even with sweaty or gloved hands), functional needs (it must be easy to open and drink from during activity, and resist leaking or being knocked), and considerations such as affordability and appearance.

The designer takes the client's brief and the user's needs and generates a range of design ideas, developing these through sketches, models and CAD, testing them against a design specification, and refining the chosen concept until it satisfies both the client's requirements (cost, feasibility, brand identity) and the user's needs (comfort, function, safety).

The maker (manufacturer) takes the finalised design and is responsible for planning and carrying out the actual production of the water bottle, selecting appropriate materials, tools, processes and quality control methods to manufacture the product to the required standard, cost and quantity, and may feed back to the designer if a design feature proves difficult, expensive or unsafe to manufacture.

These four roles interact throughout the design process rather than working in isolation: the designer must regularly check ideas against both the client's brief and user research, prototypes may be tested with real users and refined based on feedback, and the maker's practical manufacturing knowledge often feeds back into the design to ensure the final product can be produced reliably, safely, and within budget. This iterative communication between all four roles helps ensure the finished water bottle is one that the client is happy to sell, the user is happy to buy and use, and the maker can manufacture successfully.

Levels of Response (10 marks total), assessing coverage of all four roles, understanding of their interaction, and quality of written communication.

Basic [1]-[2]: Very limited response; may only name one or two roles with little or no explanation; poor structure; weak use of specialist vocabulary.

Limited [3]-[4]: Some roles identified with basic description, but coverage is incomplete (fewer than all four roles addressed, or addressed with minimal detail); limited explanation of interaction between roles.

Satisfactory [5]-[6]: All four roles identified with reasonable description of each; some explanation of how roles interact; adequate use of specialist vocabulary; reasonably organised response.

Good [7]-[8]: All four roles clearly and accurately explained with good specific detail relevant to the water bottle context; clear explanation of interaction/communication between roles; well organised with good use of specialist vocabulary; minor errors in spelling/grammar only.

Excellent [9]-[10]: All four roles explained in detail with strong, specific, well-developed reference to the water bottle example throughout; thorough, coherent explanation of the iterative interaction between all roles; wide range of accurate specialist vocabulary; high standard of spelling, punctuation and grammar throughout.