Encoding information
Changing information into another form is called encoding. Using Morse code and computer character codes, we see how it works.
All topics (8 of 11)
Chapter 1. Getting to know the computer
Chapter 2. Files and folders
Chapter 3. Information
Chapter 4. Working with text and graphics
Encoding means showing information in another form, that is, as a code. People have used it for a long time: traffic light colours stand for road rules, musical notes record sound, and library books are marked with codes. To understand a code, you have to turn it back into ordinary form, which is called decoding.
A well-known example is Morse code. Each letter is written as a sequence of dots and dashes: for instance, the signal “SOS” looks like ··· ––– ···. Only two kinds of signs are used, and computer code works on the same idea.
In a computer every character (a letter, digit or punctuation mark) has its own numeric code, written with zeros and ones. For example, the Latin letter “A” is coded as 65 and “B” as 66. The modern table that joins the letters of all languages is called Unicode, which is why Uzbek, Russian and English can be typed in one document.
Pictures are encoded too: a picture is made of tiny coloured dots called pixels, and the colour of each pixel is given by a number. Sound and video are also stored as numbers. This is why a computer can store very different kinds of information in the same way.
Key takeaways
- Encoding turns information into another form; decoding restores it.
- In Morse code, letters are written with dots and dashes.
- In a computer every character has its own numeric code.
- Pictures, sound and video are also encoded as numbers.
Practice tasks
- Give three examples of encoding from traffic lights, road signs and musical notes, and explain what they mean.
- Invent a cipher with a friend: replace each letter with the next letter of the alphabet (“A” → “B”) and encode a short sentence. Your friend then decodes it.
- Draw a picture on squared paper with 8×8 squares and encode it as a table of numbers: a filled square is 1 and an empty one is 0.
Review questions
Test yourself: think first, then reveal the answer.
1What are encoding and decoding?Show answerHide answer
Encoding turns information into a code; decoding restores the information from the code.2How does a computer store letters?Show answerHide answer
Each letter has a numeric code, which is stored as zeros and ones.3What is a picture made of?Show answerHide answer
Tiny coloured dots called pixels.
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