Coded Messages at the Seaside Kite Exhibit

Behind the Kite Display

A fourth-grade class is preparing a kite exhibit on the dry upper beach. The kites are attached to display stands, not flying. A presenter will describe each kite while a helper shows its parts. The class needs a way to send four instructions between the presenter and helper without calling across the exhibit. These are exhibit instructions, not emergency signals.

One system uses number paddles. The sender raises a paddle showing one large number. The receiver reads the number and checks its meaning in a code key. Raising, holding, and lowering one paddle takes a six-second turn.

The other system uses a small hand drum. Each message has two groups of taps, with either one or two taps in each group. A short pause separates the groups. A longer silence marks the end of a message. Each complete drum message uses a nine-second turn, including its pauses. The receiver needs to hear both groups and notice where the short pause occurs.

Before testing, the class gives both people matching keys and lets them practice. Students then compare the systems at distances of 5 meters and 20 meters. They use the same sender, receiver, code keys, and list of 12 instructions for both systems at each distance. Some instructions appear more than once.

The class changes the system and distance in separate rounds. It records how many complete instructions the receiver identifies correctly. The paddles and drum stay the same, and the tests take place during similar beach conditions. Students stay on the dry upper beach throughout the tests.