L1: Flowcharts-and-pseudoco

Flowcharts and Pseudocode
Lesson One

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• To know what we mean by an algorithm.

• To be able to recognise flowchart symbols.

• To use flowcharts to create algorithms and solve problems.

• To design, use and evaluate computational abstractions that model the

state and behaviour of real-world problems and physical systems.

Learning Objective

Success Criteria

Traffic Lights Teaser

Flo the hedgehog needs to cross the road to see her flatmates.

She needs your help to get across safely!

Traffic Lights Teaser

Next

Flo the hedgehog needs to cross the road to see her flatmates.

She needs your help to get across safely!

To get across she needs to know the correct traffic lights sequence.
What is the correct sequence?

Traffic Lights Teaser

Let’s start with the Green light, what comes next? Is it …

Green

Traffic Lights Teaser

Let’s start with the Green light, what comes next? Is it …

Green

Amber

Red

Amber

Green

Green

Traffic Lights Teaser

Let’s start with the Green light, what comes next? Is it …

Green

Amber

Red

Amber

Green

Green

Amber

Red

Green

Traffic Lights Teaser

Let’s start with the Green light, what comes next? Is it …

Green

Amber

Red

Amber

Green

Green

Amber

Red

Green

Green

Traffic Lights Teaser

Let’s start with the Green light, what comes next? Is it …

Green

Amber

Red

Amber

Green

Green

Amber

Red

Green

Green

&

Red

&

Green

Red

Amber

Red

Amber

Traffic Lights Teaser

Let’s start with the Green light, what comes next? Is it …

Green

Amber

Red

Amber

Green

Green

Amber

Red

Green

Green

&

Red

&

Green

Red

Amber

Red

Amber

Green

Traffic Lights Teaser

Let’s start with the Green light, what comes next? Is it …

Green

Amber

Red

Amber

Green

Green

Amber

Red

Green

Green

&

Red

&

Green

Red

Amber

Red

Amber

Green

Red

Amber

Green

Traffic Lights Teaser

Let’s start with the Green light, what comes next? Is it …

Green

Amber

Red

Amber

Green

Green

Amber

Red

Green

Green

&

Red

&

Green

Red

Amber

Red

Amber

Green

Red

Amber

Green

Green

Traffic Lights Teaser

Let’s start with the Green light, what comes next? Is it …

Green

Amber

Red

Amber

Green

Green

Amber

Red

Green

Green

&

Red

&

Green

Red

Amber

Red

Amber

Green

Red

Amber

Green

Green

&

Amber

Red

Red

Amber

Green

Traffic Lights Teaser

Let’s start with the Green light, what comes next? Is it …

Green

Amber

Red

Amber

Green

Green

Amber

Red

Green

Green

&

Red

&

Green

Red

Amber

Red

Amber

Green

Red

Amber

Green

Green

&

Amber

Red

Red

Amber

Green

Green

Traffic Lights Teaser

Let’s start with the Green light, what comes next? Is it …

Green

Amber

Red

Amber

Green

Green

Amber

Red

Green

Green

&

Red

&

Green

Red

Amber

Red

Amber

Green

Red

Amber

Green

Green

&

Amber

Red

Red

Amber

Green

Green

Amber

Red

Green

Traffic Lights Teaser

Let’s start with the Green light, what comes next? Is it …

Green

Amber

Red

Amber

Green

Green

Amber

Red

Green

Green

&

Red

&

Green

Red

Amber

Red

Amber

Green

Red

Amber

Green

Green

&

Amber

Red

Red

Amber

Green

Green

Amber

Red

Green

Green

Green

Traffic Lights Teaser

Let’s start with the Green light, what comes next? Is it …

Green

Amber

Red

Amber

Green

Green

Amber

Red

Green

Green

&

Red

&

Green

Red

Amber

Red

Amber

Green

Red

Amber

Green

Green

&

Amber

Red

Red

Amber

Green

Green

Amber

Red

Green

Amber

Red

Green

Amber

Green

​&

Draw

What is

the correct sequence?

Traffic Lights Teaser

Here’s the correct sequence again:

Green

Amber

Red

Red

Amber

Green

&

Traffic Lights Teaser

Here’s the correct sequence again:

Green

Amber

Red

Red

Amber

Green

&

Algorithms

Well done, you have just created an algorithm.

Algorithms

Well done, you have just created an algorithm.

•Traffic lights are usually controlled by a computer and
are programmed to follow the same sequence over and
over again.

•These sequences are called algorithms.

•Some traffic light algorithms on busy roads are very
complex, containing many steps. Others are much
shorter and are easier to predict.

Key Term

An algorithm is a set of step-by-step instructions

to describe a task or process.

Algorithms

Computer programs contain algorithms.

Pause for Thought

Smartphones are controlled by computers which have
been programmed (with algorithms) to make them do

useful things. Your phone will contain thousands of

different algorithms. What other everyday electronic devices

might be controlled by algorithms?

Open Ended

What other everyday electronic devices

might be controlled by algorithms?

Algorithm Challenge

Flo the hedgehog has made
it safely across the road and
is in need of a nice cup of tea.

Flo needs your help once again.

How can she make the perfect cuppa?

Algorithm Challenge

In pairs, write down a set of instructions that Flo could follow to make a lovely cup
of tea. Use the title: “Perfect Cuppa Algorithm”.

Next

Open Ended

In pairs, write down a set of instructions that Flo could follow to make a lovely cup
of tea. Use the title “Perfect Cuppa Algorithm”.

Algorithm Challenge

In pairs, write down a set of instructions that Flo could follow to make

a lovely cup of tea. Use the title: “Perfect Cuppa Algorithm”.

Now compare your algorithm to others in the class.
Are they similar, the same, or completely different?

Whose do you think would make the tastiest cup of tea?

Next

Perfect Cuppa Algorithm

Is your algorithm anything like this?

1. Put water in kettle and switch on.

2. Put teabag in cup or mug.

3. Wait for water to boil.

4. Pour water into the cup or mug.

5. Leave to stew.

6. Add milk if wanted.

7. Add sugar if wanted.

8. Remove teabag from cup or mug.

9. Stir well.

10. Serve and enjoy!

Algorithms

Flo says thank you for the lovely cuppa!

However, she has another problem.

Flo is not very good at reading, and she doesn’t understand
our algorithm.

Flo does like pictures.

Can we draw the Perfect Cuppa Algorithm for her?

The good news is that yes, we can!

Next

Flowcharts

We can draw the Perfect Cuppa Algorithm for her by using a flowchart.

Key Term

A flowchart is a visual method for

describing algorithms.

Pause for Thought

So putting these together, we could say that a flowchart is

a visual method for describing a set of step-by-step

instructions for a task or process.

Key Term

Remember: an algorithm is a set of step-by-step

instructions to describe a task or process.

Flowcharts

Put water in kettle and switch on.

Put teabag in cup or mug.

Wait for water to boil.

Leave to stew.

Add milk or sugar if wanted.

Pour water into the cup or mug.

Remove tea bag from cup or mug

Stir well, serve and enjoy!

Stop

Yay, I can understand

this algorithm now.
Put the kettle on!

​Start

Flowcharts

When drawing flowcharts we need to remember
the following:
We always start at the top of the flowchart.

We then work our way down the flowchart
from top to bottom, one step at a time.
The flowchart algorithm finishes at the bottom.

We need to learn the correct flowchart symbols.

Start

This box is called a

terminator.

Put water in kettle and switch on.

A rectangular box is
called a process.

Put teabag in cup or mug.

The arrows are
called flow lines.

Stop

This box is also

called a terminator.

Flowcharts Challenge 1

Now that Flo the hedgehog is refreshed after a lovely cup of
tea, she’s ready for her next adventure.

Using your knowledge of flowcharts, help Flo to forage
around the garden to find yummy worms while avoiding Sly
the fox and his friends.

Next

Flo likes nothing better than to go out at night in the dark,
looking for yummy snails to eat.

She has to watch out for Sly the fox, who likes nothing better
than to go out at night in the dark looking for yummy
hedgehogs to eat!

Flowcharts Challenge 1

Your challenge is as follows …

Help Flo to get from her starting position to her home.

Try to help her find as many yummy snails as possible.

Avoid Sly the fox and his friends at all costs!

You must draw a flowchart to plan her route…

NextNext

Flowcharts Challenge 1

You can use any combination of the following flowchart instructions:

Forward 2 steps

Start

Turn left

Stop

Turn right

Flo starts

facing upwards.

You can put any number of steps

here, e.g. Forward 1 step, or

Forward 5 steps

This is home.

Forward 5 steps

Turn left

Forward 1 step

Turn right

Flowcharts Challenge 1

Start

Forward 2 steps

Not quite sure how to get started?

Try something like this…

Start

Forward 2 steps

Turn right

Forward 1 step

Turn left

Forward 5 steps

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Open Ended

• How many snalls did you help Flo manage to eat?

Flowcharts Challenge 1 Review

Pause for Thought

How long was your flowchart?

Can you think of a way to make it shorter?

Flowcharts Challenge

•Create a new garden map for Flo.

•Draw yummy snails and scary foxes on any of the squares on your map.

•When you’ve finished, swap your map with the person next to you.

•Their challenge is to use your map to draw a flowchart, guiding Flo home while
eating as many snails as possible and avoiding the foxes.

•Your challenge is to do the same using their map!

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Let’s Bring It All Together

Key Term

A flowchart is a visual method for

describing algorithms.

Pause for Thought

So putting these together, we could say that a flowchart is

a visual method for describing a set of step-by-step

instructions for a task or process.

Key Term

An algorithm is a set of step-by-step instructions

to describe a task or process.

Draw

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Multiple Choice

What is an algorithm?

• a special type of computer
  program used by smartphones

  
  

• a set of step-by-step instructions
  to describe a task or process

  
  

• a strong and lightweight metal
  used to make aircraft

  
  

Multiple Choice

What do we call this
flowchart symbol?

• a terminator

  
  

• a process

  
  

• a flow line

  
  

Multiple Choice

What is a flowchart?

• a chart for Flo the hedgehog

  
  

• a method for making
  a great cup of tea

  
  

• a visual method for
  describing algorithms

  
  

Multiple Choice

What do we call this
flowchart symbol?

• a terminator

  
  

• a process

  
  

• a flow line

  
  

Nailing It Down

We have learned a lot today about algorithms and flowcharts.

Next lesson we’ll learn how to create flowcharts that are shorter but also
more complex and useful.

https://turtleacademy.com/playground

The instructions that you can use include:

•forward <any number>

e.g. forward 100 will move 100 steps

•right <any angle>

e.g. right 90 will turn 90 degrees

•Left <any angle>

e.g. left 90 will turn 90 degrees

Use the following website to write instructions to control
a turtle: