Theme of the lesson. Circular cycle ornaments.

Elaborate of the senior teacher of computer science Lysovtzeva O. I.

Aim: To fasten skills of using of cycles in composing of programmes. To teach pupils to create circular cycle ornaments on the paper and on the screen. To develop creative skills of pupils, vareation {variety} of thinking logical thinking {logical thinking}.

Visual material: Cardboard squares and "nets", prepared by pupils at home when doing exercise 54.
Ornamental plates on the wall, photoalbum with stained- glass panels mosaics, towels( "Rushnik"), painted eggs.

 

Plan of the lesson.

I. Organization moment.
II. Perception and comprehention of new material.
1.Let's try to understand the name of the theme. What does the word 'ornament' mean? Do you understand it? 'Ornament' (from Latin Ornamentum- decoration )- this is decoration in the form of tracery which consists of diffirent artistic elements placed simmetrically. Maybe you have seen different decorative ornaments on towels ( "Rushniks") and painted eggs, on crockery ( the teacher shows visual material).
Some of these ornaments are cycle, as they consist of identical fragments which are repeated without any changes in definite consistence in equal intervals. An ornaments created on circles are called circular.You can often find such kind of ornaments on the plates , on stained- glass panels, which decorate windows, in mosaics ( the teacher demonstrates pictures from the album).Today we'll work with circular cycle geometrical ornaments which may be placed in the circle and consist of geometrical figures repeated in definite consistence.
2.You've prepared a cardboard square and "nets". They will help you to master new material better.
Put the "Net" in 30 degrees infront of you, enclose the left side of the square to the radial, which is directed upwards and encircle it. After fixing the left side lower apix turn the square to the next radial and enircle it again. Make it consistently for each rdial of the "net" ( pupils are fulfilling the task). You have got geometrical tracery. If you paint it according to your taste at home it may become a beautiful present.

3.And now some questions. How many times did you have to circle your square? As many times as "the net" 30 degrees has radials. How many radials are there? 360: 30= 12. We've got a programmer for Tortoise ( children are looking at the page 29 in the text-book)
Repeat 12
[forward 50
right 90
forward 50
right 90
forward 50
right 90
right 30 ]
In this programme in the body of the cycle the first eight commandes answer for drawing of the square and the last command- for the turn of Tortoise to the next radial.
III. Consolidation of learned material.
1.The pupils sit down at the computers, load file with the text of learned programme and under guidence of the teacher create its different modifications. The teacher explains that for getting of the new variant of the ornament it is necessary to change the quantity of steps in the last command forward 50 or the angle of the change, or ( the last command of the cycle) and according to it- the quantity of repeating of the body of this cycle, or both.
Children have a possibility to observe variety of tracery, which are possible to get in one programme.

1) repeat 20   [forward 50 right 90 forward 50 right 90 forward 50 right 90 forward 60 right 90 right 18 ]	2) repeat 36  [forward 50 right 90 forward 50 right 90 forward 50 right 90 forward 50 right 90 right 10 ]	3) repeat 24  [forward 50 right 90 forward 50 right 90 forward 50 right 90 forward 50 right 90 right 15 ]
4) repeat 12 [ forward 50 right 90 forward 50 right 90 forward 50 right 90 forward 30 right 90 right 30 ]	5) repeat 18  [ forward 50 right 90 forward 50 right 90 forward 50 right 90 forward 35 right 90 right 20 ]	6) repeat 12  [ forward 50 right 90 forward 50 right 90 forward 50 right 90 forward 60 right 90 right 30 ]