Materials
 

1.  Computer with internet access

2. Overhead projector and eight transparencies if internet access is not available

3.  Blindfold for follow-up activity
 

Objectives

To introduce the concept of radar and sonar

To familiarize students with the concept of echolocation through a version of the game "Marco Polo"
 

Initiation

Pose the following question to the students:
"We know that bats are nocturnal and search for food at night.  Does anyone have any idea how bats find food with no light?"
 

Procedure

Explain that unlike insects and birds, many bats rely on echolocation to fly and hunt for food.  Echolocation works like the radar or sonar in planes and ships.  A bat hears the echoes and its brain works out a sound picture of the object.  It can tell if the object is prey or part of the landscape.

As an aside,  tell the students that while most humans are unable to hear the beeps of bats,  some children can.  Some moth can too and will change their flight path or drop to the ground to escape capture.

Tell the students that we will now look at some pictures showing how bats locate their food.
- Have the students access the web site:  http://www.civil.mtu.edu/~athogg/untitled.jpg
                                            OR
- Access this sit on your own and prepare transparencies using the eight pictures

Discuss and explain each picture.
 

Activity

It would be difficult to assess students' understanding of echolocation in a conventional way.  A fun hands on activity to broaden their understanding of echolocation is to play a version of the game "Marco Polo."  This activity should take place in an area the size of half a basketball court and free of furniture and obstructions.  An area should be designated for a bat cave.
-  Choose 5-10 students and one additional student to be the "Bat"
-  Blindfold the "Bat"
-  The rest of the group will be the insects.  The insects spread out within the designated area.
-  The Bat calls out "BEEP BEEP BEEP"
-  The Insects call out "BUZZ BUZZ BUZZ"
-  The insects walk around, trying to avoid the Bat
-  The Bat tries to tag the insects by listening for their sound
-  A tagged insect must sit in the bat cave.  The last person tagged becomes the new Bat.
 

 B. McCarthy  1999