Workbook

Teaching Notes &CommentaryBasic Turtle commands Prior to this worksheet some basic introduction to 'turtling' using toys like Pixie, BeeBot or Roamer and walking games are a good idea. This establishes thinking about spatial problems can be initiated with very young children (3-4 years old) using a semi-formal syntax.

This worksheet also introduces colour; the list of colour values here can also be used.

Students and children have a lot of fun with these basic commands. You can suggest target drawings (e.g. shapes, letters of your name, a car, house etc.) but on the whole adults and children are resourceful enough at this stage.

Emphasise FENCE, WRAP and WINDOW. Parts of the Logo interface. Behaviour of the Commander window.

REPEAT More fun to be had here. Emphasise the idea of nesting repeats. Emphasise the idea of rotational symmetry. The numerical exercise on the second page of the sheet is a standard Key Stage 2 mathematics exercise only this item done with Turtle Graphics. Leads to a talk about the Total Turtle Trip Theorem.

This is also a good point to introduce the use of the BITMAP menu to save and load screen. (See Traffic Project and associated notes.) Hi-tec 'colouring in' using Paint! Also copying text from the Commander into Word.

Global variables Note the use of the editor to create and edit global variables. Point out that global variables can also contain words and lists as well as numbers.

Procedures Moving on to emphasise idea of extensibility; of efficiency (writing out commands every time you need them is tedious); and programming power. Note that a a procedure called CIRCLE already exists, if circles are wanted.

Highlight use of procedures in REPEAT etc.

Describe saving and loading workspace.

This worksheet has the HOUSE problem, a Logo classic. Emphasise the notion of keeping sub-procedures simple, i.e. they do one job and no more than the one job. The super-procedure HOUSE should do the work required to get the square and the triangle in the right position.

Students can extend the HOUSE problem into creating a procedure to draw a STREET (both terraced and detached if you include an input for the gap between houses) and perhaps an ESTATE! These projects lead also onto to simple tessellation projects.

Procedures with inputs A useful extension to making procedures that draw shapes is to figure out how to draw them from the centre of the shape.

This worksheet develops a more universal polygon procedure with multiple inputs.

Tail Recursion Note the use of round brackets to clarify the arithmetic on the tail recursion line.

This worksheets introduces the use of tail recursion in drawing an equiangular spiral. Question: what is an equilateral spiral?

Conditional statements You could talk about IFELSE at this stage.

Random Numbers This worksheet starts simply. The random walk is an important idea. However, the later parts of the worksheet although very useful could be a little awesome for the arithmetically challenged (that includes me!). It ends on a moderately advanced procedure example. In a taught, supported workshop, this can be handled. Cartesian Co-ordinates An optional step. This and the previous worksheet are really useful for the animation challenge here. See also Ch 8 in Jim Muller

Using bitmaps A set of short workbooks covering the use of bitmaps and bitmapped turtles.