Digital Information - Lesson 2: Representing Information

Overview

Using everyday materials, students create devices for sending information to a partner. Each group then uses its device to send an answer to a question. Following this, students modify their devices to answer more complex answers, responding with one of four possible messages, then one of eight possible messages.

Goals

Students will be able to:

• Explain how the same piece of information can be represented in a variety of different ways.
• Use a device to represent different pieces of information
• Use patterns to represent information

Purpose

This lesson introduces the concept of sending bits of information from one place to another. While building and modifying their information sending devices students should eventually recognize that it's easier to invent a system of communication that used a combination of patterns with a simple device, rather than making a new, or increasingly complex device for each new problem. This lays the foundation for understanding how complex information is represented in computers using a combination of bits.

Getting Started (5 minutes)

Remarks

• A lot of people think that computer science is the study of computers, like the phone in your pocket or the computer on your desk. As we'll see this year, computer science actually has a lot more to do with information.

Discuss: What is your definition of information?

Have students silently write their own definition, then share with a partner, and finally have some volunteers share with the room.

• There are many ways we can think about the word "information," but one possible definition we'll explore today is that information is the answer to a question.
• We're going to investigate what it takes to send that information back and forth to one another.

Activity (35 mins)

Group: Place students in groups of two.

Distribute: Materials for students to build their binary message devices (straws, scissors, etc.)

Remarks

• Today you are going to build your own device for sending and receiving messages which you will use to answer questions that you write.

Challenge #1

Do This: Write down a question that has two possible answers. Then, build a device out of classroom supplies to communicate the answer to your question.

Rules:

• No projectiles.
• No language can be used. For example: If my question is "Is your favorite color blue or green?" I can't write the words blue and green on my device.

Do This: After students have completed their devices, choose a few groups to demonstrate their device in action. Students stand on opposite sides of the classroom. One student asks the agreed upon question. The other student uses the device to communicate the answer.

Challenge #2

Do This: Modify the answer to your question so there are now four possible answers. Then, update your device to communicate one of four possible answers to your question. Again, choose groups to demonstrate their updated devices.

Challenge #3

Do This: Modify the answers to your question so there are now eight possible choices. Then, update your device to communicate one of eight possible answers to your question.

Consider:

• Should you modify your device?
• Can you use it in a different way?
• Should you make a new device?

Do a final demonstration of devices before ending the activity.

Wrap up (10 Minutes)

• Let's wrap up by discussing how you designed your devices and what that means about the questions you can ask and the messages you can send.

Prompt: Think back to your simple two-option device from Challenge #1. Instead of changing your device and adding more options every time you added more answers, how could you simply modify the way you use your device with only two options?

Discussion Goal

Focus the discussion on why some groups created devices using unique options for each additional message, while other groups devised plans in which they reused the same device to create new combinations of the original two options.

Ultimately, groups begin to notice that, for example: instead of bending a straw in four different directions, they could simply bend the straw the same two ways multiple times.

• Sample Question: Do you like strawberry, chocolate, vanilla, or peanut butter ice cream?
• Answers: strawberry (bend straw forward once), chocolate (bend straw forward twice), vanilla (bend straw backwards once), peanut butter (bend straw backwards twice)

Assessment: Check for Understanding

For Students

Open a word doc or google doc and copy/paste the following question.

Question

Recall when you built your information sending device. Why did we decide to send a message as a sequence of two options rather than modifying our devices to represent more options?

For example: Modifications with two options

• bend straw forward once
• bend straw backwards once
• bend straw forwards twice
• bend straw backwards twice

vs. Four options

• bend straw forward
• bend straw backwards
• bend straw to the left
• bend straw to the right

Standards Alignment

• CSTA K-12 Computer Science Standards (2017): AP - Algorithms & Programming: 3A-AP-21 - Evaluate and refine computational artifacts to make them more usable and accessible.
• CSTA K-12 Computer Science Standards (2011): DA - Data & Analysis: 2-DA-07 - Represent data using multiple encoding schemes, 3A-DA-09 - Translate between different bit representations of real-world phenomena, such as characters, numbers, and images.

Next Tutorial

In the next tutorial, we will discuss CSP Internet Lesson 3, which describes how to write a protocol to send and receive binary messages..