Focus Activity One:   Discussion 
Timeframe:   10-15  minutes

Objectives:   To peak students interest in messages from outer space. 
Teaching Tips:
1.Ask students if they know any stories about messages from outer space or ET’s. 
2.Explain that in the early 1980’s some scientists began a project called SETI, which stands for Search For Extraterrestrial Intelligence.
3.SETI scientists study stars in our galaxy to find out which ones may be hosts to extraterrestrial intelligence.  They use receivers and try to “listen in” on radio signals that ETs may be sending.

Focus Activity Two:  Receiving Signals Simulation
Timeframe:   20-30 minutes
Teaching Tips: (See Materials and Preparation above to set up signals)
1. Ask students to imagine they re SETI scientists pointing a telescope at a star cluster.  As they hear messages they vote thumbs up if they think it may be a message from ETs, thumbs down if not, to the side if not sure. 
2. Play an imitated sound of static from a tape recorder.
3. Note the votes and them briefly discuss the reasons. Scientists call a signal like this “noise”.  It is produced naturally by some objects in space, and  is not a sign of intelligent life.
4. Tell the class you will now play the signal from the second star cluster.  Repeat the sound of static.  You should expect students to give the thumbs-down.
5. Tell the students to imagine the radio telescope pointed at a different star cluster, picking up more radio waves.  Play the third sound and have them vote.
6. Tell students that this actually did happen in 1967.  Scientists called the sources of the signals LGMs, for “little green men!” They later learned that such signals are from collapsed stars called pulsars, not signs of life.
7. Tell the students that we are picking up more radio waves from another star cluster.  Play the fourth sound you recorded.    Have students vote.
8. A complex repeating signal sounds as if it must have been made by someone on purpose.  Repeating patterns such as these are exactly what SETI scientists are searching for, but they have not received them ......yet.

Focus Activity Three: Decoding Messages
Timeframe:   45-55 minutes
Teaching Tips:
1. Briefly brainstorm methods of  communication used by humans and other animals.  How might extraterrestrial lifeforms communicate with each other?
2. SETI scientists have discovered that the simplest code for sending a picture by radio signals is a “binary code”. It has only two types of signals.  A barcode on an item from a store is a binary code in which the two signals are “black” and “white”.
 3. Binary code are a way to store and communicate information.  Computers and digital TVs work entirely in binary codes. 
4. One way to make a picture in binary code is by using a rectangular grid of small squares.  Each small square piece of the picture is called a bit and each bit is either black or white.

Student Activity: 
1. Pass out A Binary Message. (can be found on the documents page)  Tell students you have a set of 80 bits, a binary code, for them to turn into a picture.
2. Students fill in squares from left to right, completing rows from top to bottom.  A “beep” signal means to color in the square, and a “click” signal means to leave the square blank and go on to the next.
3. Instruct students not to distract each other.  Start reading the list of bits in a signal.
4. After all bits have been read and grids completed, have them look at each other’s grids.
5. Remind students that this is a message from Earthlings to Earthlings.  If ETs sent a picture of one of their written words we would not know their language or way of writing it down.
Group work:
1. Copy and pass out the 7 Messages from Space ( can be found on the documents page) for each group.  Make a transparency copy of each and of the Grid for Message page for yourself. 
2. Remind students that the messages have been decoded from a binary signal that was allegedly received by a radio telescope from a distant star cluster.
3. Students work to figure out the message.  Pass out the first page.  Give groups a few minutes of discussion time. Display the first page on the overhead and lay the Grid for Message on top of it.  Then remove the grid.  Ask them to share their interpretations.
4. Continue the same process with each page.  You may want to hand out and discuss pages 5 and 6 together.
5. Point out unexplained portions, and challenge students to continue.  If a message were actually received, there would be no way to know if a particular interpretation was    correct of not.  The same is true of this simulated message - they will never be told the exact intended message.
6. Encourage students to be alert to the news, because a message like this one might someday be received!