First Forward into Logo 6: Variables and Procedures

Learn to write procedures and build them into Logo programs. Learn to use variables.
Age
11 to 18
Challenge level
filled star empty star empty star
Exploring and noticing Working systematically Conjecturing and generalising Visualising and representing Reasoning, convincing and proving
Being curious Being resourceful Being resilient Being collaborative

First Forward Into Logo

Previous: FF5

 

In FF4 you investigated the instruction:

REPEAT 360 [FD 1 RT 1]

Hopefully you altered it as you saw fit and produced some exciting shapes. So it is timely to introduce you to the idea of a variable . As the word implies, a variable is something that varies, something that changes.

You may find the following a quicker way of drawing circles and circular patterns. It is called a procedure and has to be written in a particular way.

TO CIRCLE :CH

REPEAT 360 [ FD :CH RT 1]

END

Notice how the procedure is set out:

First a title / a command TO CIRCLE

then the variable :CH

followed by the instructions REPEAT 360 [ FD :CH RT 1]

then a formal closing of the procedure END

N.B. the variable, :CH could have been any letter or letters that you wish!

 



Now experiment with the procedure:


CIRCLE 3
CIRCLE 6
CIRCLE -3
CIRCLE 9
First Forward into Logo 6: Variables and Procedures


Building on this idea of a procedure we could have written:

TO CIRC :CH :ANG

REPEAT 360 [ FD :CH RT :ANG]

END

This is a procedure with two variables!

Can you anticipate what will change and what will happen now?

Can you see what is now possible?

Go on experiment! Try:

CIRC 3 3

CIRC 3 6

CIRC 3 30

What is happening?

Why not be bolder and try say:
CIRC 30 90
CIRC 30 45
CIRC 30 18 etc., etc.,
First Forward into Logo 6: Variables and Procedures


What do you notice?

What conclusions can you come to?

 

 

Next: FF7