Starter
Starter
Converting Text to Binary(ASCII)
Converting text to binary
When computers were first invented most text was represented in binary using the ASCII (American Standard Code for Information Interchange).
Converting text to ASCII formatted binary is a simple process. You simply look up the decimal value for the character in the ASCII table below, and then convert that value from decimal to binary, like we did last lesson.
Example – hello
ASCII Table
DO NOT USE THE HEX COLUMN!!!
Click to enlarge
ASCII Table
Binary > Text
Converting Binary to Text
Converting from binary to text is nice and simple. You simply convert each binary number to a decimal number and then look up that number on the ASCII table.
Practice
Convert these text examples to binary:
a. dog
b. cat
c. mouse
Convert these binary examples to text:
d. 01100101 01100111 01100111
e. 01101000 01100001 01101101
f. 01100011 01101000 01101001 01110000 01110011
Limitations of ASCII
Limitation of ASCII
- ASCII can only be used save text that uses the roman alphabet ( mainly English) so it cannot be used for Arabic, Chinese, Cyrillic, etc.
- Doesn’t include any special characters (like wingdings)
Because of these limitations new formats were introduced (such as UFT and Unicode). These allowed computers to use millions of different characters, alphabets and special characters (such as emojis, non-roman alphabets and mathematical symbols.
Plan
Prep
Download and print 30 copies of the ASCII table.
Starter
If students finish before others get them to do the online starter.
Hand out ASCII table to students while they fill in starter.
Demo
Intro ASCII to students by comparing to Morse code and then walk through the process of converting a simple word to binary on the board.
Practice
Get the students to write the first 5 letters of their name in binary.
If the finish get students to have a go at the online practice.
Learning Log
Get students to fill out learning log for lesson 3. When they reach the ASCII limitations bit, stop the class and elicit answers.
Plenary