The Nature of Technology: Storing Digital Data (PDF)

Okay, please find the markdown conversion of the provided text. ## Page 1 # The nature of technology: Storing digital data **You will learn** - how text, images and audio can be stored as digital data by a computer - how to convert between binary and decimal numbers - how to add binary numbers....

Okay, please find the markdown conversion of the provided text. ## Page 1 # The nature of technology: Storing digital data **You will learn** - how text, images and audio can be stored as digital data by a computer - how to convert between binary and decimal numbers - how to add binary numbers. A computer stores data in digital files. A digital file only contains the characters zero and one. In this unit, you will learn how text, photographs, and images can be turned into digital data so that they can be stored on a computer. You will convert everyday decimal numbers into digital data. You will use codes that will help you understand how computers store text as numbers. You will create simple images and convert them into digital data in the same way as a computer. You will discover how digital sound and video are created. **Talk about...** More than ever before, our personal data is being stored on the internet. We store some information on social media sites. Governments, banks, and online retailers save information about us online. Are you worried about your data being stored online? Is your data safe? **Curriculum reference:** Describe how different types of data can be represented in binary digital form; Convert between decimal and binary integers; Perform simple binary additions ## Page 2 # Unplugged Video and animation are created by showing a series of still images very quickly, one after the other. To create your own animation using a flick book, you will need 15 to 20 strips of paper stapled together. Draw a simple image on the first strip, then slightly change it on each of the following strips. An easy animation to draw is a bouncing ball. If you are feeling creative, draw a dancing stick character. Have finished, flick through the paper strips to animate your drawing. # Did you know? Computers and other digital devices such as televisions display realistic-looking photographs and video images. Your computer uses a system called true colour to create realistic images. True color allows the computer to store information about all the shades that make up an image. True colour allows a computer to use more than 17 million colours in an image. That is more colours than most humans can see. Storing information about a single true colour takes up the same amount of space as the computer uses to store the word 'red'. ``` 010100101 00101011000101011000 110111010 010100101. ``` **Terms Described** - binary - byte - pixel - digital data - code - true colour - bit - ASCII - media - sampling - Unicode ## Page 3 **(1.1) Digital Data** **In this lesson** **You will learn:** - what digital data is - that computers store digital data as binary numbers - how digital data can be used to store numbers, media and instructions. **Storing data** Humans store data - lots of data. We need to store data so that we can use it again when we need it. People have stored data since ancient times. Early people stored data about important events by painting images on cave walls and carving images and hieroglyphics into stone. Later people recorded their history and scientific achievements by writing on scrolls and parchment. **Spiral back** In Student Book 4 You learned about the different types of computers we use. All computers are digital devices. Digital devices store and process digital data. In this unit, you will learn what digital data is and how computers use it to store text, images and sound. Throughout history, people developed different ways to store data. They developed printing to store text and images in books. They developed vinyl records, tapes, and CDs to store and play music. In the modern world, people use computers to store and process data. Most of the data that people use today is stored in a format that computers can use. ## Page 4 # What Is Digital Data? When you communicate in English, you use letters and numbers, including 26 letters and 10 digits (zero to nine), as well as punctuation characters. A computer stores data using only digits. Data stored using digits is called **digital data**. The computer uses only two digits: the numbers zero (0) and one (1). Every file stored on a computer is made up of zeros and ones. A computer can use digital data files to store text, images, video, or audio. # What Does a Computer Use Digital Data For? The 1s and Os inside the computer can be used to store: - yes and no (or true and false) - numbers - instructions that tell the computer what to do - other digital content such as text, images and sounds. # Binary Numbers When you do maths to solve everyday problems, you use the decimal number system. The decimal system has 10 different digits: the digits 0 to 9. The 'dec' in the word 'decimal' means 10. Some people think that we started to use the decimal system because we use our 10 fingers to count with. The number system a computer uses has two different digits: 0 and 1. This is called the binary number system. The 'bi' in the word' binary' means two. A computer uses binary to store numbers. Binary numbers are used in calculations the same way as decimal values. ## Decimal and binary numbers | Decimal | Binary | | ------- | -------- | | 1 | 1 | | 8 | 1000 | | 18 | 10010 | | 100 | 1100100 | # Activity Look at the table of binary and decimal numbers. Describe any differences and similarities between decimal numbers and binary numbers that you notice. ## Page 5 ## Digital data ## Storing text using binary numbers A computer uses binary to store media. Binary can store text, images, sound, and even video. When a computer uses binary to store media it uses codes. To a computer the word 'Hello' looks like this: 01001000 01100101 01101100 01101100 01101111. Each set of eight digits is a code for a letter. The code for 'H' is 01001000. The code for 'l' is 01101100. The code for 'l' is used twice in the binary word because there are two 'l's in 'Hello'. | 01001000 | 01100101 | 01101100 | 01101100 | 01101111 | | -------- | -------- | -------- | -------- | -------- | | H | e | l | l | o | In an image, codes are used to represent colours. In a music, codes can be used to represent different instruments. Complex photographs and music files are all stored as zeros and ones. ## Activity Using the binary number codes in the word 'Hello', translate the word below to English. 01001000 01101111 01101100 01100101 ## Storing instructions using binary numbers The instructions in computer programs are stored in binary. In unit 3 you will write computer programs. The instructions are written using human alphabets and symbols. The instructions in a program must be converted into binary so that the computer can store and use them. Each binary instruction tells the computer to do a simple task. ## Acticity your task is to programme a robot to find it's way through a maze. There are just four simple instructions that you can give to the robot. these instructions tell the robot which direction to move: - one step left - one step right - one step up - one step down | Action | Code | | ------------- | ---- | | One step left | 00 | | One step right | 01 | | One step up | 10 | | One step down | 10 | The binary code for these instructions is shown in the table on the right. ## Page 6 Use the binary codes to write the program for the robot. Your program should follow the arrows shown in the diagram below to follow the green path through the maze from the blue square to the red square. The first five instructions are: 01, 11, 11, 00, 11 These instructions mean: Move one step right. Move one step down. Move one step down. Move one step left. Move one step down. Complete the list of instructions to guide the robot to the red square. ## Why do computers use digital data? Computers are powered by microprocessors. The microprocessor is the 'brain' of a computer. A microprocessor is made up of millions of tiny electronic switches. The switches in a microprocessor are like any other switch. A switch can either be on or off. A microprocessor is called a digital device because it can only understand the two switch positions - on and off. The on and off positions can be shown as 1 and 0 in binary. You have already leaned that digital data is made up of 1s and 0s. That is why a digital microprocessor can read digital data. ## Extra challenge Think about what you have learned in your computing course over the last year. List examples of activities and assignments where stored data as values, media and instructions to the computer. ## Test 1. Write down the two digits used in binary number system. 2. Write down the eight extra digits used in the decimal system that are not used in binary. 3. In your own words, explain what digital data is. 4. Describe three things a computer stores as binary code. ## Page 7 **(1.2) Reading Binary Numbers** **In this lesson** **You will learn:** - About bits and bytes - How to convert binary numbers into decimal numbers - The meaning of base 2 and base 10 **Understanding binary** **Base 10 and base 2 numbers** In the previous lesson you learned that a computer must digitally store everything it processes. You learned that you could use the binary number system to understand what digital data looks like. You also compared binary numbers to decimal numbers. The decimal number system uses 10 digits (0 to 9). Another name for the decima system is **base 10.** The value of each column in the decimal number is 10 times greater than the previous column The binary number system uses 2 digits (0 and 1). The value of each column in binary system number is 2 times greater than the previous column. Another name for the binar system is **base 2.** | | x 10 | x 10 | x 10 | | | :---- | :----- | :----- | :----- | :---- | | 1000s | 100s | 10s | Units | | | 2 | 5 | 4 | 3 | | | | x 2 | x 2 | x 2 | | | 8s | 4s | 2s | Units | | | 1 | 1 | 0 | 1 | | **Activity** Other number systems are sometimes used in computing A system is octal octal is the base 8 number system. Use the information you have learned about base 2 and base 10 to answer these questions: - How many digits does the base 8 system use? - What are those digits? - What are the values of the first four columns in the base 8 number system? Draw a table to show your answer. ## Page 8 ## How to Read Binary Numbers You can use your knowledge on base 2 to read binary numbers. The easiest way to understand a binary number is to convert the binary number into a decimal number. The binary number shown is 1101. Here is an easy why to convert the number into decimal. 1. Draw a table like the ones in the example on the previous page. It must have enough columns to hold the binary number you to convert. 2. In the first row of the table, write value of each column. Start with units in the right-hand column multiplying by each time you move right to left. 3. Write the number to convert in the second row of your table. | 8s | 4s | 2s | Units | | :--- | :--- | :--- | :--- | Put to number you want convert in the second row of your table | 8s | 4s | 2s | Units| | :--- | :--- | :--- | :--- | | 1 | 1 | 0 | 1| 4. Multiply each digit in number to convert by he column value. $1 \times 8 = 8$ \\ $1 \times 4 = 4$ \\ $0 \times 2 = 0$ \\ $1 \times 1 = 1$ 5. Add the results together to the value of binary as a decimal number 8 + 4 + 0 + 1= 13 1101 in Binary is 13 in decimal. ## *Activity* Convert these binary numbers into decimal numbers. a. 0111 b. 1001 c. 11001 d. 111001 You will need to more column the left hand die of your numbers Remember that the value the right. ## Page 9 # Reading binary numbers ## Bits and bytes Each digit in a binary number is called a **bit**. There are four bits in the binary number 1101. The word bit is short for 'binary digit' - the first letter of 'binary' combined with the last two letters of 'digit'. A bit is not very useful on its own. It can only store one of two values: 0 or 1. To binary more useful, computers group bit together. Eight bits grouped together is called a **byte**. Storing the table must show all eight in the number, even if you to the number with values. ## The language of numbers Numbers are ten. 'Ten' and 'eleven' are names of numbers in the decimal system. Every number in the decimal system has name Numbers. Numbers are not given names in binary. The binary number and the number two different numbers. **Here are images of eleven (decimal) and 11 (binary).** ## Activity Copy the table and completed the heading the table use the table convert 01100110 to decimal | x2 |x2 |x2 |x2 | x2|| | - | -| -| -| -| | ? | ? | ? | ? | ? | ?? **What goes here** ## Page 10 ## A binary to decimal shortcut Base 2 is very easy to convert in to decimal because of uses only uses the binary number table. Start at the right to the binary number, Add Together the place of every practice soon learn, convert binary practice, your head. Short try this shortcut. method comes - **Activity** The table below the values so that is from zero to nine 1. 0011 2. 0010 3. 1000 4. 0000 5. 0110 6. 0111 7. 0101 8. 0001 9. 0100 10. 1. 1001 *EXTAR CHAlleNGE* Work partner table mixup Now Your some ## *Test* 1. binary decimal 2. what byte? 3. binury show the 1 column Why is the explain 4- Explain what bass means ## Page 11 # 1.3 Adding in Binary In this lesson You will learn: - How to do simple addition in binary. - What overflow means when adding in binary. When digital data is stored as a value it can be used in calculations. For example, you have used spreadsheets in this course. When you enter a formula such as =A3+B3 in a spreadsheet cell your computer will carry out binary addition. You have also learned programming in this course. When your computer moves a sprite on screen it uses binary addition to calculate a new position. In this lesson you will learn how to do simple addition using binary. # Simple addition in decimal To do addition in binary you use the same method as addition in decimal. It will help to look at an example of how addition works in decimal before moving on to binary addition. If you lay out the addition in a table like the one on the right, it is easier to follow what happens when you add the numbers. You use the first two rows in the table for the numbers you will add together. You use the row at the bottom to record the sum. You use the shaded row to hold any values that you need to carry. # Example Decimal addition In this example you will add together the numbers 262 and 174. When do an addition you add together the numbers in each column from right to left and record the sum. Step 1: Add the Units column: Add 2 and 4 together. Think of the sum as being '06'.This will help when you do binary edition later, Write in the table. Enter the of the 10s column. Enter the 6 in the sum row of the Units Step 2: Add the 10s column: The digits in this column add up to 13. Enter the 1 in the carry row of the column. Enter the 3 in the sum row of the 10s column. |Number 1 | |Number 2| |Carry | |Sum | |100s| 10s | Units| |---|---|---| |2|6|2| |1 | 7| 4| | |0| | | | |*6*| |100 s|10s |Units| |---|---|---| |2|6|2| |1 | 7| 4| | 1|0|*| ||3|6| Step 3: Add the 100s column: The digits in this column add up to 04. There is nothing to carry. Enter the 4 in the row of the 100 column. This is completely addiction. 262 + 174+436 ## Page 12 ## Activity Draw copy of the table and in previous example. Use it to 729 and 252. # Adding in by. You use the same method to add the by. Add something difficult because you are not so familiar with number. There for addition. rule 1: 0 + 0 = 00 **rule** 0 + 1 = 0 |Number| Number | Number Number| |-| -| -| -| | 0 | 1| 1|1| | 0 ||1|1| | 0 |||0| | **Number****Number**| |-| Number Number rule 3 and + 1 10 + *rule* 4 1 and + 1 + 1 1 You can these to add other. the other so the number. what two what the rules from and other there are by the because the before In the two and data have there are some is and data you will example on the Next ## page 13 ## Adding in Binary ### Example Binary Addition In this example you will add the binary number 0011 and 1011. you will Use the for to help you binary additive. **Step 1 Adding Units** number 1 and number both table and 1 the unit column rule to says to column |Number 1 | |Number 2 | |carry | |s**um***| | 8s|4s |2s |Unit| |---|----|----|----| |6|0|1|1| |1|0|1|1| | | |1| | | | | | 0| 1+ 1 = to carry carry to columns enters 0 ins the two units addition to says that the Add add carry that column **Number** |Number 1 |Number 2 | |carry | | Sum | | 8s |*4s*| 2s | Units| Number | --- |----| ---|----|---------| | 0 | Number6 | Number1 | number1 | rule to save is it can't put number to *STEP NUMBER TWO RULE NUMBER FOUR ADDED TOGETHER =SUM 1 WITH THE RESULT* NUMBER to WITH YOU PUT YOU TWO 1 +TO COLUMN TWO SAYs COLUMNS SUM NOW FOR ## page 14