Representing and transmitting information Unit 1: The Internet Representing and transmitting information

Computer Science & Information Computer Science is commonly thought to be the study of computers themselves CS is the study of information and information processes What is your personal definition of “information”? The term ‘

Intentionally left blank for recording our definitions of ‘information’ on the whiteboard.

Mystery One of the least understood parts of the internet is how it works as a physical system Bits – Binary Digits The physical system is different from understanding what the message means Yes, the internet uses at its most basic level only two states, or binary. A binary digit – a 0 or a 1, is called a bit [portmanteau of binary digit]. Having only 2 states does not help us unless we know what those two states (a 1 or a 0 – you could also say “state A and state B” mean)

Binary Digits Binary means only two possible states. Binary question (yes / no) Binary - Not actually a term from computing Bits are used to transmit a message This message will convey information

Find a partner – relay a message Find a partner and sit next to each other Come up with a binary question (What does binary mean?) Write your question on the sheet of paper. Write what the responses are as well.

Find a partner – relay a message Now that you have your question, answering it becomes more difficult when we are separated. Build a device which will transmit the answer to your question over a distance.

Consider It should be as fail proof as possible Would your device still work if: Something in your way? Couldn’t see your partner? You were in a loud room? Partner wasn’t paying attention?

Rules Stay on your side. No walking over to your partner. No language. No writing or talking. No projectiles! You and your partner have 5 minutes to construct your device. You and a partner should come up with an agreement for what each signal means.

Challenge #2 Not all questions have only two possible answers. Invent a way with your device to send 4 possible answers! You have another 5 minutes. Go. Should you modify your device? Do you have to change how your signals are represented? Can you build upon your current system using only two states (state A and state B)?

Challenge #4 8 possible states. You have another 5 minutes. Go. If you kept only two states, then adding to your current system should be easier to remember and follow than 8 separate signals (states).

What if… Could we do this for n possible states? How many letters in the alphabet? How many words can we create using just these 26 letters? We only have 9 numbers + 0 in our number system, yet we can make numbers as large as we would like. We only have 26 letters in our alphabet, yet we can create as many words as our imagination allows. How can having only 2 states (state A and state B) allow us to send information longer than a binary yes/no or true/false?

Summary - discussion Could you use another’s device? Why / why not? What would you need to know from them? Based on what you have seen today, what are some of the limitations on the kinds of information we can send with binary messages?

Reflect, respond, print. Type name at top What binary messaging systems are CURRENTLY in use in this room, school, home, or elsewhere? Based on what you have seen today, what do you think are some limitations on kinds of info we can send with binary messages? Brake lights in a car, the bell indicating class change, smoke detectors, your phones vibration notification are all binary messaging systems.