1. A-Level Computer Science
Introduction

2. Computational thinking
Thinking abstractly, thinking ahead, thinking procedurally, thinking logically & thinking concurrently
How to use this resource
Presenting these exercises as a PowerPoint presentation allows you to use the resource in a variety of ways:
Projecting the exercise from the front of the class as a starter/plenary activity.
Printing out 3/6 slides per page to use as revision cards or a paired activity.
Carousel activity with different groups looking at different scenarios, moving between groups, adding more ideas.
Show the students the scenario. Using the computational thinking placemat as a handy reference.
Students complete the activity on the card.
The second slide in each scenario shows a typical answer. This is not exhaustive, and students may be able to elaborate further, beyond the points raised. The teacher can also pose follow up questions, with reference to the placemat to aid revision, e.g. “what are the advantages of this approach?”

3. Computational thinking
Thinking logically
Air France flight 447
On 1st June 2009, Air France flight 447 left Rio de Janeiro heading to Paris. It was a routine international flight. In the early hours of the morning, over the Atlantic Ocean, contact was lost, and the aeroplane vanished.
On investigation, the plane showed signs of a high-speed impact with water as the nose cone was flattened. This ruled out a bomb or structural break-up. It was determined that the plane crashed into the water due to pilot error.
The plane flew through a thunderstorm. Other aeroplanes had diverted that night, as is standard practice in bad weather. The pitot tubes (speed sensors) had frozen over as a result. This caused the autopilot to switch off and incorrect readings to be sent to the cockpit. This is expected behaviour, and pilots are trained to recognise this. Believing that the plane was losing altitude, the pilot pulled back on the stick to raise the nose, in an attempt to gain height. The instruments continued to show the plane falling. If an aircraft’s nose is pointed up too far, it loses speed, causing the engines to stall. The correct action is to point the nose down, gaining speed, before levelling off.
With the aid of a flowchart, show how logical thinking could have avoided this accident.
Thinking Abstractly
Thinking Ahead
Thinking Procedurally
Thinking Logically
Thinking Concurrently

4. Computational thinking
Thinking logically
Air France flight 447
Losing altitude? No
Flowchart can be extended to include levelling off after pointing the nose up/down, so it does not crash!
Yes
Is there a thunderstorm ahead?
Point nose up
Is the plane stalling? No
Yes No
Divert plane to new heading to avoid storm
Continue current course
Yes
Point nose down
Thinking Abstractly
Thinking Ahead
Thinking Procedurally
Thinking Logically
Thinking Concurrently

5. Computational thinking
Thinking procedurally and concurrently
Cup of coffee
Consider how a typical instant cup of coffee with milk and sugar is made.
Think procedurally to break this process down into a number of smaller sub-problems.
Think concurrently to identify which processes can be done simultaneously.
Outline the reasons why some of the processes can and should be done concurrently, and those that can’t.
Thinking Abstractly
Thinking Ahead
Thinking Procedurally
Thinking Logically
Thinking Concurrently

6. Computational thinking
Thinking procedurally and concurrently
Cup of coffee
Prepare water
Add water to kettle
Boil water
Add water to cup
Prepare cup
Add coffee to cup
Add sugar to cup
Add milk to cup
Cup of coffee
Students could also supply in the form of a flow diagram showing choices and decisions such as “Add Milk?” or “Add Sugar?”
Try to tease out the idea of thinking concurrently.
In this example it is clear that the cup of coffee with sugar and milk can be prepared while waiting for the water to boil.
Thinking Abstractly
Thinking Ahead
Thinking Procedurally
Thinking Logically
Thinking Concurrently

7. Computational thinking
Thinking abstractly, thinking ahead and thinking logically
Taxi driver
A taxi driver uses his experience, a GPS navigation system and radio tuned to traffic information to work out how to get passengers from A to B.
In what ways is the taxi driver able to:
Think abstractly
Think ahead
Think logically
Thinking Abstractly
Thinking Ahead
Thinking Procedurally
Thinking Logically
Thinking Concurrently

8. Computational thinking
Thinking abstractly, thinking ahead and thinking logically
Taxi driver
Possible answers to the challenge:
Thinking abstractly: using road names, road labels, traffic indicators, speed indicator, estimated arrival time on his GPS system to filter appropriate information. Awareness of black spots from accident data.
Thinking ahead: making sure there is enough fuel, planning a route to avoid closed roads.
Thinking logically: making decisions when arriving at a junction/crossroads to take a correct turning, making decisions based on traffic ahead.
Thinking Abstractly
Thinking Ahead
Thinking Procedurally
Thinking Logically
Thinking Concurrently

9. Computational thinking
Thinking ahead
New Horizons
In July 2015, New Horizons, a space probe completed a fly-by of the dwarf planet, Pluto. In order for the mission to be a success, the team at NASA had to think ahead considerably in preparation for the mission before it launched in 2006.
Research this mission, and compile a list of ways in which NASA had to think ahead.
Thinking Abstractly
Thinking Ahead
Thinking Procedurally
Thinking Logically
Thinking Concurrently

10. Computational thinking
Thinking ahead
New Horizons
Possible answers to the challenge:
Calculating how long it would take to reach Pluto
Calculating where Pluto would be in it’s orbit for successful arrival.
Calculating the necessary speed, and gravitational assists required to reach the destination at the correct time.
Planning for trajectory corrections, and having sufficient fuel.
Planning what scientific instruments would be needed/could be carried/could be built in the timescales.
Planning how to communicate with a probe with a 4 ½ hour time delay, when it can only do either scientific observation or communication at one time due to orientation.
Planning for potential unknowns, e.g. trajectory to collide with unknown moon/ice debris.
Whether this is a flyby or orbit mission. Flyby reduces the time available for scientific data to be gathered, but requires less fuel and therefore, less weight.
Possible further missions to Kuiper Belt objects.
Thinking Abstractly
Thinking Ahead
Thinking Procedurally
Thinking Logically
Thinking Concurrently

11. Computational thinking
Thinking logically
Cash point problem
Thinking logically outline an algorithm which covers the situation of a user withdrawing cash from a cash point:
Present your answer in either the form of:
a flow-chart
or pseudo code
Thinking Abstractly
Thinking Ahead
Thinking Procedurally
Thinking Logically
Thinking Concurrently

12. Computational thinking
Thinking logically
Cash point problem
Start
Update balance
Input card number
Is it the correct
PIN For this
Card?
Input PIN
OUTPUT
“Wrong PIN”
Input amount to
withdraw
Enough
Funds?
Dispense cash
Stop
“Sorry” No
Yes
BEGIN
INPUT CardNumber
REPEAT
INPUT PIN
IF PIN is wrong for this CardNumber THEN
OUTPUT “Wrong PIN”
END IF
UNTIL PIN is correct
INPUT Amount
IF there are enough funds THEN
Dispense Cash
Update customer’s balance
ELSE
OUTPUT “Sorry, insufficient funds”
END
Flowchart can be extended to include a PIN number only being allowed to be entered incorrectly up to three times before the card is retained.
This could be done with a counter and a further check on the counter.
Thinking Abstractly
Thinking Ahead
Thinking Procedurally
Thinking Logically
Thinking Concurrently

13. Computational thinking
Thinking abstractly
Maps and Abstraction
Consider the tourist map on the right of city of Manchester.
How has abstraction been used in the production of this map?
Thinking Abstractly
Thinking Ahead
Thinking Procedurally
Thinking Logically
Thinking Concurrently

14. Computational thinking
Thinking abstractly
Maps and Abstraction
Areas of the city have been colour coded
Road name labels have been added
Picture icons of various attractions have been added
Key locations have been labelled with a circled number
A key has been added with icons for key building such as car parks and post offices
Major ring roads and the river have been coloured differently to clearly stand out
Thinking Abstractly
Thinking Ahead
Thinking Procedurally
Thinking Logically
Thinking Concurrently