Binary
Time 1.3 hrs

Difficulty Beginner
Prerequisites Computer Science A
Departments Science
Authors Sandra Kuipers
Groupings Individual
Minimum Year Group None

### Blurb

In this unit you will explore binary, bits and bytes.

This work is shared under the following license: Creative Commons BY-SA-NC

### Outline

 Learner OutcomesStudents will: ... Competency Focus ... Interdisciplinary Connections ... ReflectionWhat was successful? What needs changing? Alternative Assessments and Lesson Ideas? What other Differentiation Ideas/Plans could be used? ... CreditsAny CC attribution, thanks, credit, etc. "Binary code" thumbnail by Christiaan Colen is licensed under CC BY-SA 2.0

5 mins
Binary
All 0s and 1s
• Computers are complex machines that work by storing the simplest of values:
• 0 (also known as false or off)
• 1 (also known as true or on)
• This is called binary or base-2.
• This unit won't teach you lots about binary, but there are other units that will.
• For now you just need to know that computers use binary to store data.
• In Computer Science we call a single 0 or 1 a bit (short form binary digit)
• If you understand binary, you will get the following joke:

• Don't worry if you don't get it...you might soon!

5 mins
Bytes
8 bit
• In computers, groups of 8 bits are stored together in a Byte.
• b stands for bit, B stands for Byte.
• A byte will look something like this:
• 10010111
• A byte can be used to:
• Store a number of 0 to 255.
• Store a letter of the alphabet, and some other special symbols like !, ? or @.
5 mins
One and Zeroes
Getting Started

15 mins
Counting with Binary
Explorable

20 mins
ASCII
Letters
• ASCII (pronounced as-key) is a system that computers use to store characters (letters, numbers, special symbols).
• Instead of storing a letter directly, ASCII stores characters as numbers.
• For example A is the number 65 and a is the number 97
• You can use the chart below to see how different characters are represented as numbers in ASCII (click for a larger version):

• I could use ASCII to write my name (Jody Hubert) as follows:

74 111 100 121 32  72 117 98 101 114 116

• Take some time now to write your name in ASCII.
• However, as computers can only store binary, a computer would store my name as:

01001010 01101111 01100100 01111001 00100000 01001000 01110101 01100010 01100101 01110010 01110100

Gigabytes
Many, Many Bytes
• Because computers store so much information, we often don't count in bytes, but use groups of bytes.
• You may have heard of a gigabyte, or other groups such as kilobytes and megabytes.
• The table below shows what these things are:

1 bit (b) = a single 0 or 1

1 byte (B) = 8 bits

1 kilobyte (KB) = 1024 bytes

1 megabyte (MB) = 1024 kilobytes

1 gigabyte (GB) = 1024 megabytes

• This means that a gigabyte is a collection of 8,589,934,592 bits.
• Or 1 x 8 x 1024 x 1024 x1024
• That's a lot of data!
10 mins
Petabytes
Even more Numbers
• If you want some even bigger numbers:

1 terabyte (TB) = 1024 gigabyte

1 petabyte (PB) = 1024 terabytes

1 exabyte (EB) = 1024 petabytes

1 zettabyte (ZB) = 1024 exabytes

1 yottabyte (YB) = 1024 zettabytes

• It is very hard to imagine how big these numbers are, but the image below might help you get a handle on the size of a petabyte:

20 mins
Finishing Up
Evidence
• To show what you have learned in this unit:
• Give the document a title
• Write your name in ASCII using regular numbers
• Write your name in ASCII using binary numbers
• Make a guess at how many bytes of information are contained in the whole English language version of Wikipedia.
• How did you come up with that number?

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