In the prior unit, Circuits and Switches, students learned how binary numbers 0 and 1 are represented in electrical states (on/off). In the Digital Information unit, students learn how binary numbers can actually be used to create a language and logic for digital devices.

- Understanding some of the ways computers represent, process, and display letters, numbers, sounds, and images
- Comparing the binary number system to the decimal number system
- Adding binary numbers

- Using binary numbers to represent the alphabet (ASCII)
- Decision-making with AND/OR statements

**Goals and Objectives**

Students will learn:

- How the binary system can be used to represent images
- What a pixel is and how it's used to represent images
- How the two-state (on and off) nature of transistors can be used to represent information
- How to convert decimal numbers to binary numbers and vice versa
- How to add binary numbers
- How to represent letters of the alphabet with the 8-bit ASCII code

**Time to Complete Online Lessons:** about 50 minutes

**Preparation**

- Read the background information.
- Review and prepare for supplemental lesson ideas and group activities.
- Organize materials and equipment:

- Student computers with an active Internet connection

- Copies of the student handouts for this unit that you plan to use

- Printouts of the interactive whiteboard images (optional)

**Procedures**

- Have students complete the online activities:

Throughout the unit, facilitate the development of new vocabulary introduced in this unit. - Students who are not at the computer can work on supplemental lesson ideas and group activities.
- After students complete the online materials, they can:

- Demonstrate their knowledge of the one-to-one correspondence between binary-counting numbers and decimal-counting numbers by completing the table of values online or in the Binary Numbers Student Handout

- Perform simple addition problems between two binary numbers, and check their answers
- Suggest a list of other items that can be represented by a binary system, such as the possible answers in a yes/no survey, a true/false test, a game of 20 questions, and so forth
- Explain in their own words why ASCII code is used and what it's used for

The following handouts can be used with this unit to enhance learning. Each handout is briefly described below. To see the actual handout, click the link "handout."

This handout teaches students:

- How the on/off state of transistors relates to the binary number system used by computers to store numbers, words, sounds, and pictures
- How computer display screens are made of tiny dots called pixels
- How simple pictures can be created in a grid using 1s and 0s to indicate which grid squares are colored in and which are not

This handout teaches students how to count in binary numbers and how to add them.

**Binary Counter**

Use this handout to direct a group activity where small groups of students use their bodies to form a binary counter to represent numbers from 0-15.

**ASCII Computer Code**

Using a chart of all letters and their binary code this handout helps students:

- Understand how letters of the alphabet can be expressed by binary numbers
- Write their name in ASCII code
- Write and translate secret messages written in ASCII

This handout teaches AND/OR logic, showing students how binary numbers can be used to represent yes/no and determine outcomes to simple statements.

**Interactive Whiteboard Images**

The images linked below are pertinent to this unit. You can project the images on an interactive whiteboard and use them in class discussions or activities.