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COMPUTATIONAL THINKING L3: PATTERN RECOGNITION & ALGORITHM DESIGN YEAR 8 COMPUTER SCIENCE @MRC-ACADEMY

LEARNING OBJECTIVES In this lesson you will: Further your UNDERSTANDING of what is meant by Computational Thinking. UNDERSTAND what is meant by pattern recognition and algorithm design. So that you can: USE these methods to solve complex problems.

LAST LESSON We introduced the method of computational thinking which was designed to help solve complex problems. How many stages are there? What are the stages called? Can you explain the first two stages?

4 STAGES OF COMPUTATIONAL THINKING STAGE 1: DECOMPOSITION Breaking a problem down into smaller, more manageable parts which are easier to solve. STAGE 2: ABSTRACTION Removing unnecessary details so that only the main, important points remain. STAGE 3: PATTERN RECOGNITION Finding similarities among small problems that could help fix the larger problem efficiently. STAGE 4: ALGORITHM Step-by-step instructions to solve the problem.

PATTERN RECOGNITION The third stage to solving a complex problem is pattern recognition. When we decompose a complex problem we often find patterns among the smaller problems we create. The patterns are similarities or characteristics that some of the problems share. By finding these patterns it will allow us to solve the complex problem more efficiently.

TASK 1: CATS On a piece of paper sketch 3 to 5 different cats. Reflect on the activity: Are there any common characteristics in your cats? What are they? Did this make drawing more than one cat easier or harder?

CATS & PATTERN RECOGNITION All cats share common characteristics. Among other things they all have eyes, tails and fur. They also like to eat fish and make meowing sounds. Because we know that all cats have eyes, tails and fur, we can make a good attempt at drawing a cat, simply by including these common characteristics. In computational thinking, these characteristics are known as patterns. Once we know how to describe one cat we can describe others, simply by following this pattern. The only things that are different are the specifics.

PROBLEM SOLVE: HOTEL TYCOON Remember our hotel? We have already used decomposition and abstraction to help solve our complex problem of arranging a sightseeing tour around London. It’s now time to use pattern recognition to get one step closer to putting a plan in place.

TASK 2: PATTERN RECOGNITION --- 10min task 2 Player Complete in Worksheet If the tour is to run every weekday (Mon to Fri), what are the necessary properties that never change for our route planning to each landmark? What are the specifics that do change? WRITE your ideas in the worksheet. EXTENSION: Research how Google uses pattern recognition and consider the advantages this brings.

TASK REVIEW What are the common characteristics in our route planning? What are the specifics that would change for each location? How do you think this helps us put a plan together?

PATTERN SPECIFICS HOTEL TUBE STOP TUBE LINE LANDMARK HOTEL GREEN PARK JUBILEE LINE WESTMINSTER BIG BEN DISTRICT LINE MONUMENT ST PAUL’S

ALGORITHM DESIGN An algorithm is a plan, a set of step- by-step instructions to solve a problem. It is important to plan out the solution to a problem to make sure that it will be correct. In an algorithm, each instruction is identified and the order in which they should be carried out is planned. An algorithm must be clear. It must have a starting point, a finishing point and a set of clear instructions in between.

TASK 3: ALGORITHM DESIGN --- 10min task 1 Player Complete in Worksheet It is now time to put the plan together. Have a look at the map and work out the route. Create a step-by-step plan for the tour route. EXTENSION: How would you describe computational thinking to an alien? How would you convince the alien it is important?

TASK REVIEW Did you find creating the algorithm easy? Do you think it would be this easy if you didn’t decompose or abstract the problem?

PROBLEM SOLVE: HOTEL TYCOON Congratulations! You have organised the sightseeing tour around London. It will not be long before you start making some profit.

ALGORITHM DESIGN Algorithms are often used as a starting point for creating a computer program, and they are sometimes written as a flowchart or in pseudocode. If we want to tell a computer to do something, we have to write a computer program that will tell the computer, step-by-step, exactly what we want it to do and how we want it to do it. Computers are only as good as the algorithms they are given. If you give a computer a poor algorithm, you will get a poor result – hence the phrase: ‘Garbage in, garbage out.’

NEXT LESSON Disaster at the hotel has broken out. You need to apply COMPUTATIONAL THINKING to get the guests to safety.