New
New
Year 8

Representing characters

I can encode, transmit and decode short messages using different coding schemes.

New
New
Year 8

Representing characters

I can encode, transmit and decode short messages using different coding schemes.

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Lesson details

Key learning points

  1. Character coding schemes, like ASCII are used to represent letters, numbers and symbols in digital form.
  2. In computing, every piece of information is represented as sequences of 0s and 1s.
  3. The length of a representation is measured by the number of symbols it contains.

Keywords

  • Coding scheme - a system where a code is used to represent something

  • Encode - converting information from one form into another

  • Decode - converting encoded data back into its original form

  • ASCII - a character set that represents each character with a unique numerical value

Common misconception

The representation length does not include any spaces.

The representation length is the total number of symbols in the sequence including spaces.


To help you plan your year 8 computing lesson on: Representing characters, download all teaching resources for free and adapt to suit your pupils' needs...

The coding schemes are provided as additional materials for this lesson. It may help pupils to have these printed out to refer to throughout the lesson.
Teacher tip

Equipment

Pupils will need access to the coding schemes modelled in this lesson.

Licence

This content is © Oak National Academy Limited (2025), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).

Lesson video

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Prior knowledge starter quiz

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6 Questions

Q1.
What does the word representation mean in computing?

the colour of your screen
the internet connection speed
Correct answer: the form in which data is stored, processed and transmitted
the brand of your computer

Q2.
What do we call something that stands for something else, like an emoji or a road sign?

Correct Answer: Symbol

Q3.
Put these actions in order for representing a picture on a computer:

1 - take a photo
2 - convert the photo into binary
3 - store the binary data as a file
4 - display the image on the screen

Q4.
Which of these is a reason to use different representations for different situations?

Correct answer: some representations are clearer or more useful depending on the context
to make things harder
so computers use more memory
to use more colours

Q5.
Match each keyword to its meaning:

Correct Answer:representation,the form in which data is stored, processed, or transmitted

the form in which data is stored, processed, or transmitted

Correct Answer:symbol,something that stands for something else

something that stands for something else

Correct Answer:binary,the system of 0s and 1s used by computers

the system of 0s and 1s used by computers

Correct Answer:information,data that has been organised and given meaning

data that has been organised and given meaning

Q6.
What is the name for the system of 0s and 1s that computers use to represent all types of information?

Correct Answer: Binary

Assessment exit quiz

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6 Questions

Q1.
Match each example to the correct keyword:

Correct Answer:encode,turning the word "cat" into 99 97 116

turning the word "cat" into 99 97 116

Correct Answer:decode,turning "99 97 116" back into "cat"

turning "99 97 116" back into "cat"

Correct Answer:ASCII,the standard that uses 65 to represent "A"

the standard that uses 65 to represent "A"

Correct Answer:coding scheme,a set of rules for changing letters into numbers

a set of rules for changing letters into numbers

Q2.
What is the main purpose of a character coding scheme like ASCII?

Correct answer: to represent letters, numbers and symbols in digital form
to store images
to create sound effects
to make computers run faster

Q3.
In computing, how is every piece of information ultimately represented?

as letters and words
Correct answer: as sequences of 0s and 1s
as colours
as pictures only

Q4.
Put these steps in order for encoding and decoding a message:

1 - write the original message
2 - encode the message using a coding scheme
3 - transmit the encoded message
4 - decode the message back into its original form

Q5.
When measuring the length of a representation, what should you include?

only letters
only numbers
Correct answer: all symbols, including spaces
only punctuation

Q6.
If the word "Hello" is written in Morse code as ".... . .-.. .-.. ---", what is the representation length of this code?

Correct Answer: 19, Nineteen

Additional material

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