Computer Science LearnITWithMrC ⛯ Year 7 Year 8 Year 9 GCSE
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Lesson 2 - Sequencing

Flowcharts and sequencing

Software can be used to create sequences in a flowchart, to view onscreen simulations.

Examples include:
  • Flowol
  • Logicator
  • Crocodile Clips

Basic flowchart symbols

Name Symbol Usage
Terminator

Starts or stops a process.
Input or output

An input is data received by a computer. An output is a signal or data sent from a computer.
Process

An instruction or a command.
Decision

A decision, either yes or no. For example, a decision based on temperature that turns a central heating system on or off.
Line tool

Connects the symbols. The arrow indicates direction.


Flowcharts and sequencing

Software can be used to create sequences in a flowchart, to view onscreen simulations.

Examples include:
  • Flowol
  • Logicator
  • Crocodile Clips

Basic flowchart symbols

Name Symbol Usage
Terminator

Starts or stops a process.
Input or output

An input is data received by a computer. An output is a signal or data sent from a computer.
Process

An instruction or a command.
Decision

A decision, either yes or no. For example, a decision based on temperature that turns a central heating system on or off.
Line tool

Connects the symbols. The arrow indicates direction.


control

Algorithms

Algorithms are sets of step-by-step instructions for the computer to follow. They are at the heart of all computer programs.

You can think of an algorithm as similar to a food recipe. If you make a sandwich, you follow a set of steps to put the different ingredients together. You bring ingredients together, assemble them as you like, and produce a final product - the sandwich. If you were asked to write down instructions to make a sandwich, you could create a written algorithm.

Within your sandwich algorithm you would need to specify:

  • inputs - ingredients and quantities
  • the process - recipe or method
  • output - what the finished sandwich will be like
Input processing output diagram

Use of algorithms

Algorithms are used in all areas of computing. Examples include:

  • PageRank - Google's search engine uses a highly effective algorithm called PageRank to find the best matches for search terms. PageRank decides which pages are listed first when you search for something. This algorithm is highly sophisticated and played an important role in Google Search's success.
  • Weather forecasting - the Met Office uses weather forecasting algorithms to model weather patterns and make predictions.
Laptop running a program to track the predicted path of a hurricane

Algorithms are a great way of automating computer decisions. However, automating processes can lead to errors.

For example, the Amazon website uses algorithms to decide the price of products. In 2011, the price of a book called 'The Making of a Fly' (about the molecular biology of a fly) jumped to £14 million as the pricing algorithms used by Amazon to set and update prices started outbidding each other. This raised the book price.

Task 1 - Traffic Light Sequence

Watch the 'Traffic Light Sequence' video below then download the worksheet and finish the sequences.

Write down the sequences in the sheet below

Task 2 - Creating bridge lights using Flowol

Look at how your final Flowol Bridge light should work

Update your objectives

control

You should now be able to assess yourself against your objectives:

  1. I can explain how simple algorithms work
  2. I can create simple linear algorithms.
  3. I can develop a control solution for a system that uses two flowcharts operating in sequence

  • Learning Objectives

  • I can explain how simple algorithms work.
  • I can create simple linear algorithms.
  • I can develop a control solution for a system that uses two flowcharts operating in sequence.

Flowcharts and sequencing

Software can be used to create sequences in a flowchart, to view onscreen simulations.

Examples include:
  • Flowol
  • Logicator
  • Crocodile Clips

Basic flowchart symbols

Name Symbol Usage
Terminator

Starts or stops a process.
Input or output

An input is data received by a computer. An output is a signal or data sent from a computer.
Process

An instruction or a command.
Decision

A decision, either yes or no. For example, a decision based on temperature that turns a central heating system on or off.
Line tool

Connects the symbols. The arrow indicates direction.


Resources