Computers follow instructions
Computer Science · Key Stage 1 · The School
Machines that obey
A computer is a machine that follows instructions EXACTLY. It is not clever on its own. It cannot guess what you meant. Tell a robot to walk forward, but forget to say stop at the wall, and it walks into the wall. It is not being silly. It is doing what it was told. A list of instructions like that is called a PROGRAM.
Order matters
Try these instructions for brushing your teeth. One: brush your teeth. Two: put toothpaste on the brush. That is the wrong way round, so you brushed with a dry brush. A computer would do exactly the same thing. It follows the SEQUENCE it is given, step by step. It never skips ahead to check whether the next line would have made more sense.
Be the robot
Here is a game worth playing. One person is the robot. One person gives instructions to cross the room. Two steps forward. Turn left. Three steps forward. The robot does ONLY what is said, and nothing else at all. You will find out very fast how precise instructions have to be. That discovery is where programming starts.
Here are instructions for getting ready for school. One: put on shoes. Two: get out of bed. Three: eat breakfast. Four: get dressed. Five: brush teeth. Six: leave the house. Follow them EXACTLY, in that order. You put your shoes on in bed, and you get dressed after breakfast. Now put them in a sensible order. Notice that nothing was wrong with any single instruction. The ORDER was the bug. That is true of most real programs too.