Flowers*

Drawing circles and arcs with Logo instructions give students the opportunity to discover and apply important ideas in geometry. Although the circles drawn with the turtle are not circles in the strict sense (they are actually many-sided polygons), students can think about how a circle is drawn. Ask them to model the turtle and walk in a circle themselves, describing what they are doing. Arcs are pieces of circles, which allows students to apply fractions and the concept of degrees to a real problem.
This example introduces the notion of variables.

Procedures

Logo Practice Board

Logo Tip

Define the following procedure to draw an arc:

to arc :step :degrees
repeat :degrees / 10 [forward :step right 10]
end

Try arc 10 90 to draw a quarter of a circle.

How can you draw a petal?

Think about the heading of the turtle when it finishes drawing a quarter circle. Where should it be heading before drawing the second arc for the petal? Try:

arc 10 90
rt 90
arc 10 90
rt 90

Spirals

Extensions: Students can create their own flower garden, using the turtle as a drawing tool. They will define procedures for the flowers with an arc procedure as a sub procedure. They can import a background and animate bees and birds as final touches.

* Copyright 1998 Logo Computer Systems Inc.

Logo Practice Board