Computer Science for Class 4

Chapter 1. How does a Computer Work

Ø A Computer is an electronic machine that can do fast and correct calculations in addition to many other works.

Ø The word “computer” comes from a Greek Word “compute” which means to calculate.

Ø Computer works on the principle of input, process and output.

Ø Input is typing data into the computer.

Ø Process is calculating or sorting the data.

Ø Output is the result of processed data.

Ø Data is raw facts or figures.

Ø Information is processed data

·        CPU: Central Processing Unit

·        ALU: Arithmetic and Logic Unit

·        CU  : Control Unit

·        MU : Memory Unit

·        VDU: Visual Display Unit

·        LCD: Liquid Crystal Display

·        CD : Compact Disk

Differences between man and computer

1.     Man works slowly but computer works fast.

2.     Man can imagine and think but computer cannot imagine and think.

3.     Man gets tired and bored of doing the same work after some time but a computer doesn’t get tired and bored of doing the same work even after a long period of time.

4.     Man cannot do different types of work at the same time but computer can do different types of work at the same time.

5.     Man do sometimes wrong but computer always does accurately.

6.     Man can remember limited information but computer can store lots of information.

Chapter 2. Characteristics of a computer

Characteristics of a computer are

1.     Speed 

2.     High storage capacity

3.     Versatility

4.     Accuracy

5.     Diligence

 Limitations of a computer are

1.     A computer cannot take its own decisions and provide itself with input.

2.     It cannot detect wrong input given by the user and thus gives wrong result

Therefore limitation of computer is that it can work only with the help of human beings.

Computers are used for

1.     Problem-solving

2.     Playing games

3.     Arts & entertainment

4.     Internet

5.     Documentation

6.     Accounting

7.     Scheduler

Versatility means being able to do many different functions or activities.

Diligence Working continuously without getting tired.

Chapter 3. Input and Output Devices

Input Devices are used to enter the data into a computer.

Examples of Input devices are:

*Keyboard   *Mouse    *Joystick   *Trackball   *Touchscreen   *Touchpad

 *Microphone   *Scanner   *Barcode Reader   *Light Pen

Output Devices are used to see the result on the computer screen.

Examples of Output devices are:

*Monitor * Printer *Speaker

Storage Devices are used to store data and information.

Examples of Storage devices are:

*Hard Disk   *Compact Disk    *Pen Drive

Mouse is a pointing device used to select objects or texts and to draw pictures on the computer.  Mouse is moved over a flat surface, usually a mouse pad.

Joystick is a pointing device .It is mainly used to play games on a computer.

A Trackball looks like an upside –down mouse. The trackball remains stationery. It has a ball that rotated to move the cursor on the screen.

Touch Screen allows the user to enter input by simply touching the display screen. Touch screen is used in Mobile Phones and ATMs

The touchPad is commonly used in laptops.

Scanner is an input device that reads and scans the text and pictures given on a paper into computer understandable text and pictures. There are two types of scanners: Flat Bed scanner and Hand-held scanner.

A Barcode Reader is used to read barcodes printed on items in a shop, meant for sale.

A Light Pen is a pen-shaped pointing device. It is connected to the monitor.Light Pens are used to draw pictures on the screen. We can also select objects on the screen by pointing at them with a pen. It is mostly used by engineers and designers. Light pen is especially used by commenters of cricket matches to mark on screen what they want to show.

Although printer is an output device, it works like “Input-Process-Output” itself .The blank Paper is the input, printing on paper inside is processing and hard copy is the output.

        

CPU is the processing device of the computer. CPU consists of three parts  

·        ALU (Arithmetic and Logic Unit): It does all calculations like additions, subtractions, etc.

·        CU   (Control Unit): It controls all the activities of the computer .It Tells other parts of the computer what they should do.

·        MU (Memory Unit): It stores data and information temporarily.

Chapter 4. MS- Windows 7

Operating System: An Operating system is software that controls all the activities between a user and the hardware of the computer.

MS Windows 7 is an OS, developed by Microsoft Company.

Software: Software is a set of computer programs and gives instructions to the computer to perform many tasks.  

Icon: The small pictures on the desktop representing some computer functions are called icons. Example: - My Computer, Recycle Bin, etc.

A disk drive is a piece of hardware in computer used for reading or writing data on disk.

You can easily restore the deleted files or folders from Recycle Bin.

File: File contains the information stored in the computer.

Folder is a collection of files .It may contain other folders also.

You can easily create a New Folder using Windows Explorer.

You can easily rename, delete, copy or move a folder.

The background of the desktop is called wallpaper.

A Keyboard usually has 104 keys.

Screen Saver: Moving pictures or text seen on the computer screen is called screen saver.

You can easily move a window from one location to another, by dragging its title bar.

Window size can be adjusted by dragging its edges.

Clipboard is a temporary area in memory to store your work while using the cut or copy command.

Flip means to move the image to a certain position

Rotate means to rotate an object around center point at a specified angle.

  

Chapter 5. MS-Paint

MS-Paint is a simple drawing program.

Ribbon contains several tabs and groups like tools, shapes, images and clipboard.

The image group provides you with commands such as to crop, resize, rotate and select the image.

View tab provides you with commands such as zoom in, zoom out and 100%

Rulers, gridlines and full screen commands are present in group of view tab.

Print command is used to take printouts of your drawing on a paper.

You can easily set your picture as a desktop background.

You can choose more colors from the edit colors command present in colors group.

Flip or rotate commands are present in Image group.

Print command is used to take printouts of your drawing.

When you cut a part of your drawing, it is temporarily stored in clipboard.

Rotate means to turn the image around a central point

Home and View are two tabs in ribbon.

The crop option can be used to delete a part of the drawing.

  

Answer the following questions:

1.      Name the command to view the drawing on full computer screen.

By clicking Full Screen command in Display Group we can see the picture on whole screen of the monitor.

2.      What is the use of copy command?

The copy command is used to make duplicate copy of selected part of drawing.

3.      Write the use of following commands.

Zoom In: Zoom In command is used to see the image in a bigger size.

Zoom Out: Zoom Out Command is used to see the image in a smaller size.

Gridlines: Gridlines helps us to resize picture accurately.

Rulers: Rulers helps us draw picture of given size.

4.      Write down the steps to save your drawing.

Click on Microsoft Paint button > Click on Save As > The Save As Dialog box appears >Type the file name > Click on Save

Chapter 6. Logo Primitives

1.      What is LOGO?

Ans: LOGO is a simple computer language.

2.      What is the full form of logo?

Ans: The full form of logo is Language of graphic oriented or Logic Oriented Graphic Oriented

3.      Who was the developer of LOGO?

Ans: LOGO developed by Wally Feurzeig.

4.      What is the shape of a turtle?

Ans: The shape of a turtle is like a triangle.

5.      How many parts of logo windows?

Ans: There are two main parts of logo windows.

6.     Name the two main parts of logo windows.

Ans: 1. Main screen 2. Commander window.

7.   What does the recall list box display?

Ans: The recall list box displays all the commands that we have written/typed in the ‘command input box.’

8.   What is logo turtle?

Ans: A small triangle that acts like a LOGO pen is called Logo turtle.

9.   How many parts of logo turtle?

Ans: Logo turtle has two parts 1) Head 2) Tail.

10.  What is meant by head?

Ans: Head means the top pointed end of the turtle is called its head.

11.  What is tail?

Ans: Bottom part of the Turtle is called tail.

12.  What is another name of logo commands?

Ans: Another name of logo commands is primitives.

13.  Where do we type the commands?

Ans: We type commands in Command Input Box

14.  What is meant by primitives?

Ans: LOGO commands are also called logo primitives.

15.  In how many parts the commander window is divided? Name them.

Ans: The commander window is divided in three parts.

1.     Command input box

2.     Recall list box

3.     Command Buttons.

16.  How many basic primitives in logo?

Ans: There are nine basic primitives in logo.

17.  Write the steps to start logo.

Ans:    1. Click on the Start button

  2. Choose All programs

            3. Select and click on Microsoft window logo.

            4. Click on "OK" button to start MSW logo screen.

18.  Write the three uses of logo.

Ans: Logo can be used to do the following tasks:

1.     Drawing Pictures

2.     Typing Text

3.     Solve mathematical problems.

19.  How to Exit From MSW Logo?

                    1. Simply clicking into Close Button

2. Clicking Exit from File Menu

3. Typing Command “BYE” in Command input box and then        pressing Enter Key on keyboard.

20.  Which command is given to make the turtle take a half turn?

Ans: Command RIGHT 180 is given to make the turtle take a half turn.

21.  Which is the home position of a turtle?

Ans: Home Position is the Centre of the Drawing Area

22.  Which command do we use to clear text from the commander window?

Ans: We use to CT  command to clear text from the commander window.

23.  How can we make the turtle reappear on the screen?

Ans: We can make the turtle reappear on the screen by giving ST command.

24.  Which command does bring the turtle back to the centre of the screen?

Ans:  HOME command brings the turtle back to the centre of the screen.

25.  Which command is given to make the turtle take a half turn?

Ans: Command RIGHT 180 is given to make the turtle take a half turn. 

26.  What should be given between the primitives and the number of steps?

Ans: Space should be given between the primitives and the number of steps.

27.  Which command is typed to move the turtle 50 steps backward?

Ans: BK 50 is typed to move the turtle 50 Steps backward.

28.  Which command clears the recall list BOX area?

Ans: CT command clears the recall list BOX area.

29.  What is the use of RT?

Ans: RT command is used to turn the turtle’s head to the right.

30.  What will be the effect of typing FD50(No Spaces) in the command input 
      box?

Ans:  We will get an Error Message: “I don’t know how to FD50”

31.  What will be the effect of typing BK  -20  in the command input box?

Ans: Turtle moves forward 20 steps.

32.  What will be the effect of typing FD  -50  in the command input box?

Ans: Turtle moves backward 50 steps.

33.  What Happened when you typed FD 800?

Ans: The Turtle moved forward and at 500 steps the screen came to an end, so it started again from bottom of the screen to finish the remaining 300 steps. 

Definitions:

v FORWARD or FD command moves the turtle in forward direction.

v BACKWARD or BK command moves the turtle in backward direction.

v RIGHT or RT command turns the turtle’s nose in right direction from the turtle’s current position.

v LEFT or LT command turns the turtle’s nose in left direction from the turtle’s current position.

v HIDETURTLE or HT command is used to make the turtle disappear from the screen.

v SHOWTURTLE or ST command is used to make the turtle reappear on the screen.  

v SETHEADING or SETH command turns the turtle’s nose left or right from HOME position.

v HOME command brings the turtle to its HOME position.

v PENUP or PU command tells the turtle to pick up its pen.

v PENDOWN or PD command tells the turtle to put its pen down.

v PENEREASE or PE command is used to erase the incorrect lines drawn by the turtle.

v PENPAINT or PPT command is used to tell the turtle to start its drawing again.

v PRINT or PR command prints the command in the Recall List Box.

v LABEL command prints the text in drawing area.

v CLEARTEXT or CT command is used to erase all the commands from recall list box.

v CLEARSCREEN or CS command is used to erase all the drawings.

Write the full form of given short forms.

FD : FORWARD                               HT : HIDETURTLE

CT : CLEARTEXT                            PR :  PRINT

RT: RIGHT                                        BK :  BACKWARD

ST : SHOWTURTLE                        CS : CLEARSCREEN

LT : LEFT                                          SETH : SETHEADING

PU: PENUP                                        PD: PENDOWN

PE: PENERASE                                 PPT: PENPAINT

Arrange the jumbled words:

1.    UPC		14.  IEFL
2.    UTNIP		15.  OLFERD
3.    ADTA		16.  LLAWPRAPE
4.    UTOTUP		17.  OZOM
5.    SESCORP		18.  OPYC
6.    ORINMFTAINO		19.  TUC
7.    ATDA		20.  IFLP
8.    CUCATERA		21.  ORATET
9.    EMMROY		22.  OLOG
10.  IDLIEGCEN		23.  ABLEL
11.  ALECNADR		24.  RIPNT
12.  CION		25. IGRHT
13.  ESDKOTP		26.  ELFT

27 BRBINO
28 USM
29 ORPUCDT
30 DAD
31 IDIVDE
32 UMTLIPYL
33 ABLEL
                                                       

Answers: 1. CPU 2.INPUT 3.DATA 4.OUTPUT  5.PROCESS 6.INFORMATION 7.DATA 8.ACCURATE   9.MEMORY 10. DILIGENCE   11. CALENDER 12.ICON 13.DESKTOP 14.FILE  15. FOLDER 16.WALLPAPER 17.ZOOM 18.COPY   19.CUT 20.FLIP 21.ROTATE 22.LOGO 23.LABEL 24.PRINT 25.RIGHT 26. LEFT 27.RIBBON 28.SUM 29.PRODUCT 30.ADD 31.DIVIDE 32.MULTIPLY 33.LABEL

Shortcut Keys:

To permanently delete a File or Folder            : Press Shift + Delete key

To Copy a File or Folder                                      : Press Ctrl + C Key

To Paste a File or Folder                                      : Press Ctrl + V Key

To Cut a File or Folder                                         : Press Ctrl + X Key

To Open RUN dialog box                                     : Press Windows Key + R

To Close Paint Window                                        : Press Alt + F4

To Save our drawing or any other work               : Press Ctrl + S

To Open a file or any other work                         : Press Ctrl + O

To Open a new Drawing                                      : Press Ctrl + N

Press and hold shift key for drawing perfect square.

Press and hold shift key for drawing rounded square.

You can increase or decrease the size of brush being used using Ctrl + [+] key or Ctrl + [-]

Cut and Paste removes the original object .Copy and Paste retains the original object at its original position.

Chapter 7. LOGO Calculations

To do mathematical calculations in LOGO, you can use PRINT and LABEL commands.

Mathematical operators like +,-,*, / are also used for calculations.

When PRINT command is used, result is displayed in commander window.

When LABEL command is used, the result is displayed in the drawing area.

Sum is the output of addition of two numbers.

Difference is the output of subtraction of two numbers.

Product is the output of multiplication of two numbers.

Quotient is the output of division of two numbers.

Examples:

1.    Addition of Numbers

PR 2+5

PR SUM 2 5 

PR 2+3+5

PR (SUM 2 3 5)

2.    Subtraction of Numbers

PR 5-3

          PR DIFFERENCE 5 3

3.    Multiplication of numbers

PR 6*6

PR PRODUCT 3 4

PR (PRODUCT 3 4 5)

4.    Division of Numbers

PR 8/4

PR QUOTIENT 36 6

Chapter 8. Introduction to MS Word 2010

MS Word 2010 is a word processor program used for typing documents.

Word Processor is a software that deals with word processing.

Components of MS word screen are:

§  Title Bar displays the name of document.

§  Quick Access Toolbar contains save, redo, undo etc.

§  Ribbon contains different tabs and groups.

§  Scroll Bars used to view the documents. There are two scroll bars.

1.    Horizontal Scroll Bar shifts the documents left and right.

2.    Vertical Scroll Bar shifts the document up and down.

§  Rulers mark the position of words in document.

1.    The Horizontal Ruler measure the width of the document starting at the left margin

2.    The Vertical Ruler measures the length of the document starting from the top margin.

§  Status Bars displays the information like page number and number of words in a document.

You can easily change font color, font size, font style etc.

You can choose save, close, open and exit options by clicking on File tab.  

How to start MS Word 2010?

Click on Start Button >> click All Programs >> Click Microsoft Office >> Select and Click MS Word 2010

We can add commands to the visible Quick access toolbar by clicking on the down arrow mark to its right and clicking on any command from the drop down menu.

The size of letters in the text is called the Font Size.

  

Important Shortcut Keys

To make the Text Bold                   : Ctrl + B

To make the Text Italic                   : Ctrl + U

To make the Text Underlined         : Ctrl +  I

To create a New Document            : Ctrl + N 

To Save a File                                 : Ctrl + S

To Open a File                                : Ctrl + O

How to Exit MS Word 2010?

                  I.            Click File >> Click Exit 

Or

               II.            Simply click the “close” button.

Click on “Yes” if you want to save the document else click “No”. The MS Word will be closed.