Giraffe Lookout: Choose an Air Model

An Air-Pad Display for the Lookout

The zoo is planning a small science display beside the benches at its giraffe lookout. Visitors will gently squeeze a sealed air pad and compare drawings that explain what is inside. The design team wants the display to explain more than the pad's outside shape. Before choosing a drawing, zoo educator Nia tests air with a large plastic syringe that has no needle. She uses gentle pressure and keeps the syringe pointed away from people. The tests use room-temperature air.

In Test A, Nia pulls the plunger to the 60-milliliter mark. She covers the tip tightly with her finger. Keeping the tip covered, she presses the plunger inward and holds it at two different marks. The graph records the space occupied by the trapped air at the start and during the two presses. With gentle pressure, she does not get the plunger to zero. When she releases the plunger, it moves back to nearly its starting mark. She uses the same syringe throughout this test.

In Test B, Nia connects the syringe to a small, flexible air pouch through a short tube. She checks that the connections are sealed. The pouch begins nearly flat. As she presses the plunger, the pouch puffs out. Air can move through the tube, but the connected syringe, tube, and pouch are closed to the surrounding air. In Test C, she instead starts with 60 milliliters of air in the syringe alone. She leaves the tip open while pressing to 30 milliliters. Some air escapes through the tip. Then she seals the tip.

The team can read the syringe marks and see the pouch change shape. They cannot see individual air particles with their eyes. Their proposed drawings use dots as symbols for these invisible particles. A dot stands for many particles, not one actual particle. The drawings are not actual-size views or exact counts. Each design must explain which material it includes and what its symbols mean. The team will judge the designs by how well they fit the test evidence.