Magnetic Shade Clips on the Desert Trail

Shade for a Desert Display

At a desert botanical trail, educator Laila sets up a small shade cloth over a display of young cactus plants. The cloth helps protect the display during the brightest part of the day. Visitors and wind sometimes pull the cloth loose. Laila wants a way to attach the cloth to the stand and remove it when the display closes.

The team tested a magnet with four sample objects. The magnet pulled a steel washer and a steel strip toward it. The magnet did not pull an aluminum disk, a wooden bead, or a plastic button. The team planned to place steel strips along the top of a model stand. A magnet could be sewn into each cloth corner, with the cloth between the magnet and a steel strip.

The team made a model with four cloth corners and two steel strips. They gave each design three short fan bursts. They also timed how long an adult took to remove the cloth. Design A used one magnet, stayed attached for 1 of 3 bursts, and took 4 seconds to remove. Design B used two magnets, stayed attached for 3 of 3 bursts, and took 6 seconds to remove. Design C used three magnets, stayed attached for 3 of 3 bursts, and took 12 seconds to remove. Design D used two magnets, stayed attached for 2 of 3 bursts, and took 4 seconds to remove.

The starting goals are for the cloth to stay attached during three fan bursts and for an adult to remove it in 8 seconds or less. The design limit is to use two magnets or fewer and make no holes in the shade cloth. The model used a small fan, so the team will need more testing before using a design on the real trail.