by Paul Curzon, Queen Mary University of London
What is an algorithm? It is just a set of instructions that if followed precisely and in the given order, guarantees some result. The concept is important to computer scientists because all computers can do is follow instructions, but they do so perfectly. Computers do not understand what they are doing so can’t do anything but follow their instructions. That means whatever happens the instructions must always work. We can see what we mean by an algorithm by comparing it to the idea of a self-working trick from conjuring.
If you follow the steps of a self-working trick you will have the magic effect even if you have no idea how it works. Below is a a demonstration of a self-working magic jigsaw trick (you can download it from here https://conjuringwithcomputation.wordpress.com/resources/ print it, cut out the pieces and do it yourself, following the instructions below).
The step of the trick are.
- 1) Count the robots (ignore the green monsters and the robot dog)….There are 17.
- 2) Swap the top two pieces on the left with those on the right lining the jigsaw back up
- 3) Count the robots ….There are 16. One has disappeared.
Magically a robot has disappeared! Which one disappears and where did it go? Was it swallowed by a green monster, did it teleport away?
How did that happen anyway?
By following the steps you can make the trick work…even if you haven’t worked out how it works, a robot still disappears. You do not need to understand, you just need to be able to follow instructions. It is a self-working trick. Follow the steps of the trick exactly and the robot disappears. It is just an algorithm. Self-working tricks are just algorithms for doing magic. When you follow the steps of the trick you are acting like a computer, blindly following the instructions in its program!
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