Loci

Programme Outline

Jamie introduces the idea of loci with the aid of a guide dog, which can be taught to follow simple rules as it chooses its path. Katie demonstrates movement according to a rule and constructs a circle.

Circular loci create the cells that are the basis of 'Find Me' - the latest mobile phone service. Jamie uses his phone to locate a bank whilst Katie visits the network centre to see just how the system knows where Jamie is. We see how overlapping regions make mobile communication possible across the country.

Jamie builds the locus of points a fixed distance from a given line and explains how to deal with going round the ends.

He then visits a guide dog training centre, where the dogs' ability to judge and maintain distances is crucial. A basic skill is to walk along a pavement keeping equidistant from buildings and the edge of the kerb. Ashton, the dog, demonstrates the resulting path and goes on to show that she can follow the same rule between two converging lines, bisecting the angle in the process!

Katie's looking at property and fantasises that if she were a soap star on 'Emmerdale' the ideal location for a luxury apartment would be halfway between the studios and the Emmerdale village, where outside scenes are filmed. She constructs the perpendicular bisector of these two locations on a map of Leeds and checks out likely properties in the vicinity of her line.

The presenters are tested on their construction skills in 'Tick or Trash' this week. Katie makes a typical error and explains how she went wrong. She reminds viewers that compasses, a ruler and a sharp pencil are essential ingredients for exam success.