THE IDEA
Think in steps
An algorithm is a precise, unambiguous sequence of instructions. A program is an algorithm written for a machine.
Try the puzzleLEARNING TO CODE
Code is just
careful instructions.
Programming is mostly about saying exactly what you mean.
STEP by step
41 of 66 Pages in her published paper
- Think in steps
- Expect bugs
- Start small
- Precise beats clever
A computer follows instructions in order, precisely, with no common sense to fill the gaps. That is what makes coding hard at first, and what makes it learnable. Here is what programming really is, where the ideas came from, and where to start.
Plain English, with the sources linked.
THE SHORT ANSWER
Steps, then bugs, then more steps.
Every program, however large,
is built from precise instructions.
THE HABIT
Expect bugs
Every coder writes mistakes. Finding and fixing them, called debugging, is a normal part of the job.
The famous moth
THE START
Blocks, then text
Many learners begin with drag-and-drop blocks, then move on to a typed language once the ideas click.
Where to startA QUICK PUZZLE
Can you spot
the bug?
Here is an algorithm for a cup of tea. A person would quietly fix it. A computer would follow it exactly as written.
Pick the step you think is in the wrong place.
WHERE TO START
Four habits for
your first week.
Write the steps in plain English
Before any code, list the steps for a small task on paper. If a step could be read two ways, split it until it cannot.
Start with blocks if you like
Block-based tools let you see the logic without worrying about typing. Move to a text language when you want more control.
Read the error, then change one thing
Error messages are clues, not verdicts. Change one thing at a time so you know which change fixed it.
Build something you want
A quiz, a timer or a tiny game teaches more than a long tutorial you never finish. Keep it small enough to finish this week.
TWO MOMENTS WORTH KNOWING
Programs before
computers existed.
The ideas behind coding are older
than the machines that run it.
41 of 66
Pages in her published paper
Lovelace translated an article about Charles Babbage’s Analytical Engine and added her own notes, which made up 41 of the 66 pages. Her final note, Note G, set out how the machine would calculate Bernoulli numbers.
ADA LOVELACE · 1843
A real moth
What engineers found in a relay
Engineers working on the Mark II at Harvard found a moth stuck in the machine and taped it into their logbook, labelled “first actual case of bug being found”. The logbook is now in the Smithsonian.
HARVARD MARK II · 1947
The moth did not invent the word: engineers had called small faults in machines bugs since at least the 1870s. It was the first actual bug, which is the joke in the note.
CODING FACTS
Five things worth
knowing first.
The first published program
Lovelace’s notes appeared in Taylor’s Scientific Memoirs in August 1843. Her table for calculating Bernoulli numbers is often called the first computer program.
More than sums
Lovelace argued that if musical relations could be expressed mathematically, the engine might compose elaborate and scientific pieces of music: an early hint that computers handle more than numbers.
Algorithms from key stage 1
Since September 2014, computing has been a national curriculum subject in England, replacing ICT. At key stage 1, pupils learn what algorithms are and that programs follow precise and unambiguous instructions.
Two languages at key stage 3
At key stage 3, the curriculum asks pupils to use two or more programming languages, at least one of which is textual, to solve a variety of computational problems.
Blocks built for beginners
Scratch, released in 2007 by the Lifelong Kindergarten group at the MIT Media Lab, is a free programming tool designed for young people aged 8 to 16.
QUICK QUESTIONS
Coding, answered.
Short answers to the questions beginners ask most.
What is an algorithm?
A set of precise, step-by-step instructions for doing a task. The national curriculum in England asks pupils at key stage 1 to understand what algorithms are, how they are implemented as programs on digital devices, and that programs execute by following precise and unambiguous instructions.
Who wrote the first computer program?
Ada Lovelace is usually credited. Her notes on Charles Babbage’s Analytical Engine, published in August 1843, end with Note G, a table showing how the machine would calculate Bernoulli numbers. That table is often called the first computer program.
Why are mistakes in code called bugs?
Engineers were calling small faults in machines bugs long before computers; the Smithsonian notes that Thomas Edison talked about bugs in electrical circuits in the 1870s. In 1947, engineers on the Harvard Mark II found a real moth in the machine and taped it into their logbook as the first actual case of bug being found.
Is coding taught in schools in England?
Yes. From September 2014 computing replaced ICT as a national curriculum subject. By key stage 3, pupils are expected to use two or more programming languages, at least one of which is textual.
Which language should a beginner learn first?
There is no single right answer. Scratch, a free block-based tool from the MIT Media Lab released in 2007, was designed for young people aged 8 to 16. Many learners then move on to a text language such as Python, which was created in the early 1990s.
Where the facts come from
Updated
- National curriculum in England: computing programmes of studyGOV.UK, Department for Education
- Consultation outcome: replacing ICT with computing from September 2014GOV.UK, Department for Education
- Ada Lovelace and the Analytical EngineBodleian Libraries, University of Oxford
- Log book with computer bug (1947)Smithsonian National Museum of American History
- Celebrating 10 years of ScratchMIT News
- History of the softwarePython documentation