Detailed Notes: Logo (Part - 1) | Computer - Class 5 PDF Download

Introduction

• You must have kept dogs and cats as pets in your house, but have you ever had a turtle as your pet? In this chapter you will befriend a clever turtle who will teach you a new language called LOGO. 

Logo stands for Logic Oriented Graphic Oriented. You can draw pictures as well as do calculations with LOGO. 

• Logo is a highly interactive language that uses a triangle-shaped cursor called a "turtle". Logo's language (also called LOGO) has got words, sentences and texts just like every other language. 
• The first version of LOGO developed by Seymour Papert in the United States used an electronic robot that resembled a turtle.

Getting Started in Logo 

• LOGO is one language that children will enjoy and would love to learn. Perform the following steps to start working in LOGO:

1. Click on Start -> Programs -> PC Logo Program group -> PC Logo (exe) 

Commands in Logo

• The simple Logo drawing commands move the turtle forward and backward and turn it right or left. 

Basic Commands

• Forward e.g. forward 200 [makes a line 200]
• Back e.g. back 100 [goes back 100]
• Right e.g. right 90 [turtle turns right through a 90 degree angle]
• Left e.g. left 45 [turtle turns left through a 45 degree angle]
• PenUp 
• PenDown
• HideTurtle
• ShowTurtle
• Penerase
• PenPaint
• HideTurtle

Abbreviated commands for the list above (these can be typed into the command window)

• FD 200 
• BK 100 
• RT 90
• LT 90
• PU
• PD
• HT
• ST
• PE
• PPT
• CS

Forward or FD

• This moves the turtle forward by a number of steps.

• ? Forward 50

OR

• FD 50  

• When the turtle moves, a line is drawn there.  

Back or BK

• This moves the turtle backward by a number of steps. (See Figure 5.2.6)  

• ? Back 20

OR ?

• BK 20        

Right or RT

• This rotates the turtle right by a certain number of degrees (0 degrees to 360 degrees] (See Figure 5.2.7)  

•  ? Right 90

OR

• ? RT 90  

• Insert screen shot of result of above action  

Left or LT

• This rotates the turtle left. You can move the turtle from 0 degree to 360 degrees.      
• ? Left 90

OR

• ? LT 90  

 Hide Turtle or HT

• This will hide the turtle. This means that you will not be able to see the turtle on the screen after issuing this command. 
• If you give any command to draw, the turtle will still draw the line. It will continue to work even when it is not visible.    
• ? Hide Turtle

OR        

• ? HT  

Show Turtle or ST

• If you want the turtle to be visible again on the screen then give the Show Turtle command.   
• ? Show Turtle

OR

• ? ST  

 Clear Text or CT

• This will clean the text area. Every command that has been written in the Text window will be erased.
• ? Clear Text       

OR

• ? CT  

 Clear Screen or CS

• This will clean the Graphic area, that is, everything drawn there will be erased.  

PenUp

• The PenUp command lifts the turtle's pen up from the screen, so when it moves, it does not draw any line. This allows you to reposition the turtle without drawing.

PenDown

• The PenDown command puts the turtle's pen back down on the screen, so when it moves, it draws a line again. This allows resuming drawing after repositioning with PenUp.

PenErase

• The PenErase command erases any lines drawn and leaves no trace when the turtle moves. It is like lifting the pen up.

PenPaint

• The PenPaint command puts the pen back down to resume drawing lines as the turtle moves. It cancels the effect of PenErase.

Commonly Asked Questions

Q.1.Given below are the statements about LOGO. Select the correct statements.

1. LOGO screen is divided into three parts.

2. The upper part of the screen where the turtle moves and draws figures is called Graphic Area.

3. The lower part of the screen where we give different commands is the text area.

(A) 1 and 2
(B) 1 and 3
(C) 2 and 3                                                          
(D) Only 1
(E) Only 3
Answer: (c)

Explanation
Correct Option:
(C) Statements 2 and 3 are correct about LOGO.
Incorrect Options:
(A) Statement 2 is correct, whereas statement 1 is incorrect. Therefore, option (A) is incorrect.
(B) Statement 3 is correct, whereas statement 1 is incorrect. Therefore, option (B) is incorrect.
(D) Statement 1 is incorrect. Therefore, option (D) is incorrect.
(E) Not only is statement 3 correct, but statement 2 is also correct. Therefore, option (E) is incorrect.  

Q.2.Fill in the blanks:

1. The instructions you give to the turtle are called _____.
2. The question mark (?) on the lower part of the screen where we give commands is called _____.
3. A small triangle that appears in the center of the screen is called ____.
(A) Primitives, Prompt, Turtle                    
(B) Prompt, Primitives, Triangle
(C) Order, Prompt, Arrow                          
(D) Primitives, Primitives, Turtle
(E) Prompt, Commands, Triangle  

Answer: (a)

Draining Figures Using LOGO 

• As discussed before, you can use LOGO to draw different interesting shapes. 
• As you type out the commands in the Text window, you can see your figure form in the Graphic window. Some examples are given below:  

Straight Vertical Line

• ? FD 100 <Enter> 

Straight Horizontal Line

• ? RT 90 <Enter>
• ? FD 100 <Enter>

Triangle

• ? Home <Enter>
• ? FD 40 RT 90 FD 50 HOME <Enter>

Rectangle

• ? FD 100 RT 90 FD 200 RT 90 FD 100 RT 90 FD 200 <Enter> 

Steps

• ? FD 30 RT 90 FD 30 LT 90 FD 30 RT 90 FD 30      

Square

• ? FD 100 RT 90 FD 100 RT 90 FD 100 RT 90 FD 100      

Spiral:

• REPEAT 36 [FD 5 RT 10]
• This draws a spiral by repeating a small forward and right turn 36 times.

Octagon:

• REPEAT 8 [FD 30 RT 45]
• This repeats a forward and 45-degree right turn 8 times to make an octagon.

Circle with Dotted Lines:

• PENERASEREPEAT 360 [FD 1 RT 1 PENPAINT FD 1 PENERASE]
• This lifts the pen up and down while drawing a circle to make dotted lines.

Smiley Face:

• PENERASECIRCLE 50PENPAINTCIRCLE 10 RT 90 FD 15 LT 180 FD 30 LT 180
• Draws a solid circle with two dotted eyes and a smile.

Wave Pattern:

• PENERASEREPEAT 180 [FD 5 LT 1 FD 5 RT 2]
• Varies left and right turns to make a wave pattern. 

Commonly Asked Questions

? FD 500 RT 90 FD 50 RT 90 FD 50 RT 90 FD 50

(A) Circle                                                             

(B) Triangle

(C) Square                                          

(D) Oval

(E) None of these

Answer: (C)

Explanation

Correct option: (C) Square: 

The instructions given to the turtle in LOGO

? FD 500 RT 90 FD 50 RT 90 FD 50 RT 90 FD 50 <Enter>

will form a square.

Q.2.Which of the following commands is/are used to move the turtle towards the right?

(A) FD                                                  

(B) RT

(C) LT                                                   

(D) HT

(E) None of these  

Answer: (b)

Explanation

Correct option: (B) RT: 

Is used to move the turtle towards the right.