GCSE (9-1) Computer Science
Mark Scheme
J277/02: Unit 2.1 Computational Thinking
Question Answer Marks Guidance
1
  • Abstraction -> Filtering out unnecessary details...
  • Decomposition -> Breaking a complex problem down...
  • Algorithmic Thinking -> Logical steps to solve a problem...
 3
1 mark for each correct line.
2a Any two from:
  • Current Location (GPS)
  • Destination
  • Speed limit of roads
  • Traffic data
  • Road layout/map data
 2
Do not accept: "Time" or "Distance" (outputs).
2b Any two from:
  • Colour of the car
  • Number of passengers
  • Music playing
  • Weather (unless affecting speed)
  • 3D shapes of buildings
 2
3
  • Breaking down a complex problem (1)
  • into smaller, more manageable parts/sub-problems (1).
 2
Both parts are needed. "Breaking it down" is only 1 mark.
4
  • Level 1: Top box labelled SportsDaySystem (1).
  • Level 2: Three boxes below connected to top: Register, Record, Display (1).
  • Level 3 (Register): Connects to InputName & AssignHouse (1).
  • Level 3 (Record): Connects to EnterTime & CalculatePoints (1).
  • Level 3 (Display): Connects to ShowWinner & PrintCertificates (1).
 5
Note: The diagram must show a hierarchy. Flowchart arrows are incorrect. Lines should just be connectors.
5
  • Branch 2: UpdatePositions / MoveEnemies / MovePlayer (1).
  • Branch 3: CheckCollision / CheckLives / CheckGameOver (1).
  • Branch 4: UpdateScore is given (verify no duplicate).
 3
1 mark for each logical module added.
6 Any two benefits:
  • Different people can work on different parts of the program at the same time (1) reducing development time (1).
  • Smaller modules are easier to debug/test (1) because you can isolate errors more quickly (1).
  • Modules can be reused in future programs (1) saving time on rewriting code (1).
 4
7
  • Input: Length AND Width (Both needed) (1).
  • Process: Area = Length * Width (1).
  • Output: Area / Result (1).
 3
8
  1. start() -> Terminator / Terminal / Start/Stop (1).
  2. count... -> Process / Rectangle / Action (1).
  3. if score... -> Decision / Diamond (1).
  4. print... -> Input/Output / Parallelogram / Data (1).
 4
The question specifically asks for the name, not the drawing.
9 currentTemp = sensor.read()
if currentTemp < 18 then
  heating = "on"
elseif currentTemp > 21 then
  heating = "off"
endif

Marking Points:
  • Correct inputs/reading (1).
  • Correct first condition (< 18) (1).
  • Correct second condition (> 21) (1).
  • Correct logical structure (IF/ELSEIF) (1).
 4
Do not penalise syntax errors provided the logic is sound.
10
  • Computers have limited processing power/memory (1).
  • Including too much detail (like the colour of clouds) would slow the simulation down (1).
  • Abstraction allows the program to focus only on the physics/flight mechanics which are the purpose of the simulation (1).
 3
OCR 2026