The Kinetic Gallery Signal Test

A Signal Flap in the Kinetic Gallery

The Children's Museum was building a signal for its Kinetic Gallery. A wooden ring rolled down a track and struck a hinged flap. When the flap swung, visitors could see that a collision had happened. The team wanted the flap to swing far enough to see while keeping the sound quiet. They used a ring of the same size in every test.

First, the team tested a bare wooden flap. They released the ring from three marks on the track. The low mark was 20 centimeters from the flap, the middle mark was 40 centimeters away, and the high mark was 60 centimeters away. The team kept the track, ring, and flap the same. After each collision, they measured the flap's swing distance and the ring's rebound distance. They also rated the sound: 1 clap was quiet, 2 claps was medium, and 3 claps was loud.

The results were recorded like this: low mark—flap swing 12 centimeters, ring rebound 3 centimeters, sound 1 clap; middle mark—flap swing 22 centimeters, ring rebound 5 centimeters, sound 2 claps; high mark—flap swing 35 centimeters, ring rebound 7 centimeters, sound 3 claps. The ring did not stop at the flap, because it rebounded a short distance after each collision.

Next, the team placed a thin cork pad on the front of the same flap. They used the middle mark and repeated three trials. With the cork pad, the flap swung 18, 19, and 18 centimeters. The ring rebounded 4, 4, and 5 centimeters. Each collision made 1 clap. The team planned to use these observations to ask new questions about the collision and choose a signal design.