Information in Radio Waves
Information Theory: Background
The ability to communicate has been a key part of the development of human society. Communication could not happen without information being transferred in some way. Communication between two people face to face has many dimension (or channels) such as: facial expression, tone of voice, body language, vocabulary, any many more…. Communication at a distance can have many dimensions as well: yelling at the top of your voice (if possible), flashing lights, smoke signals. Can you think of others ….? In this unit of study we will be exploring the nature of information transfer and how it has been applied to the transmission of information using radio waves.
Claude Shannon was MIT mathematician who is considered by most to be the inventor of information theory. He did many experiments with information in the form of yes and no answers to simple questions. Shannon developed a method for measuring the information content in a signal. He called the information content of amessage, “entropy”. Entropy depends not only on the number of possible outcomes—in the case of a coin toss, two—but also on the probabilityof it happening. Improbable events, or surprising information, need a lot more questions to guess the message because they tell us more information we didn’t already know—just like the situation of taking a helicopter to school. (Bell 1999)
In this unit you will work in teams to play some interesting and fun games related to information theory. As you play consider that many have stated that the Thesis work of Dr. Claude Shannon was the most important thesis ever written. His creative and playful imagination is what has brought about the technology that we all use on a daily basis.
Enrichment Resources:
Remote Sensing Primer .The encyclopedia of earth science: Planetary science
NGSS Performance expectations:
HS-PS3-5 / Develop and use a model of two objects interacting through electric or magnetic fields to illustrate the forces between objects and the changes in energy of the objects due to the interaction.HS-PS4-5 / Communicate technical information about how some technological devices use the principles of wave behavior and wave interactions with matter to transmit and capture information and energy.
Unit Breakdown:
This unit introduces the principle of information theory, that the amount of information in a message can be quantified and measured. While this theory has had an immense impact on society through engineered telecommunications technologies, the emphasis here is on how discoveries in physical science continually cause scientists to re-interpret the observations they make of the distant objects that we can only detect remotely. An emphasis is placed on passive remote sensing as a tool for hypothesis development and testing.
Possible order of teaching:
- Unit pre-test with starter activity
- Lecture presentation with games
- Follow up and reflection on games
- Summative Quiz
References
Bell, Tim, Ian H. Witten, and Mike Fellows. Computer Science Unplugged. Canterbury, New Zealand, 1999. Computer Science Unplugged. Mar. 2010. Web. July 2013. <
"Claude Shannon." Wikipedia. Wikimedia Foundation, 14 July 2014. Web. 15 July 2014. <
Forisek, Michael, and Monika Steinova. "Didactic Games For Teaching Information Theory." International Conference on Informatics in Secondary Schools: Evolution and Perspectives. ISSEP, Jan. 2010. Web. July 2013. <
Forisek, Michael, and Monika Steinova. "Didactic Games in Teaching Information Theory." Teaching Fundamental Concepts of Informatics: 4th International Conference on Informatics in Secondary Schools - Evolution and Perspectives, ISSEP 2010, Zurich, Switzerland, January 13-15, 2010: Preceedings. Vol. 5941. Berlin: Springer, 2010. 86-100. Print. LNCS.
Jacobberger, Patricia. "Remote Sensing." Encyclopedia of Earth Science. 1007 ed. Vol. 10. Chapman and Hall, 1997. Print.
Navalgund, Rangnath R. "Remote Sensing." Resonance 6.12 (2001): 51-60. Web.
Information Theory: Assessment of prior knowledge
Electromagnetic radiation: Circle true or false for each statement.
True or falseLight that we see with our eyes is the only form of electromagnetic radiation
True or falseEM radiation may travel through the vacuum of space
True or falsethe speed of light depends on the type of material that it is travelling through
True or falseAll different wavelengths of light travel at the same speed in a vacuum
Match the following terms with a picture that best represents them drawing a line between the word and image:
WavelengthPhase
Amplitude
polarization
Information Theory: Starter Reflection
In pairs or groups of three, reflect on these two scenarios:
Scenario A:You are a college student and to earn a little more money you volunteer to be a test subject in a psychological experiment. The experiment requires that you are placed in a sensory deprivation chamber that is completely dark, soundless, of constant temperature, and motion free (you are motion free, no moving hands, arms, fingers, etc….). Are there any ways that you can receive or send information to the outside world?
Scenario B:Imagine a primitive member of the human race who is sitting quietly on a ledge overlooking a valley in the White Mountains. You are hungry and you need to gather information about your environment so that you might be able to successfully gather and hunt for your food. What types of information might help you and how can you ‘receive’ those pieces of information?
Randomly select a group to present each reflection to the class. Five minutes at the end of the group’s presentation should be dedicated to class feedback or comment.
Activities: Games for investigating Information Theory
Game 1: Guess a sentence
Rules:
- Your group will be given a sentence of four to six words with each of the letters (including spaces) as unknowns.
- Your job is to guess the sentence exactly by asking yes/no questions only.
Examples:
'is this letter a b?'
'does it come before m in the alphabet?'
Scoring/Reflection
You were each given a different sentence
did they each contain the same amount of information ?
Why did one have more information than another?
Game 2: Vincent, Phil, Shep **
Background: This game is designed to encourage students to reflect upon how information can be transmitted when certain rules or restrictions are applied by the transmission channel.
Materials needed:
1 chair per team
Blindfolds for the robots of each team
One object to be picked up by the robot (preferably light weight)
Game set up:
•Align the chairs in the front of the classroom and designate a minimum distance where the navigators will stand and call out to the robots.
•Robots should all be blindfolded outside the classroom and escorted into the room so that they are standing behind the chair at the beginning of the first round.
•Prepare activity cards for each navigator team. There will be two activities:
•The robot must be instructed to simply sit down in the chair and wait for the next activity
•The robot must reach beneath the chair and raise the object that is there above their heads.
•The first team to complete the tasks is the winner.
A non-competitive approach may be to make the goal of the class to get all the robots to accomplish their task and when all are completed the reward is given.
**(refer to presentation slides for background on the scientists at the MIT Haystack Observatory who’s names we used for this game)
Game 3: Text Messaging Game
Rules
•One student is given a copy of text
•That student must re-write the text using only uppercase letters or numbers and spaces
•The goal is to use as few symbols as possible
•Once completed the other partner must reconstruct the message losing 2 pts for each incorrect word.
The score is 1 pt. for every character that was saved. Add up the points from saved characters and subtract deductions for incorrect words.
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