The Classroom Supply Drop Challenge

Where Will Loose Supplies Go?

A fifth-grade class is planning a supply-return station beside its classroom message board. A wide tray will catch small items that slip from a low shelf. Before choosing where to place the tray, the class makes predictions and collects observations. The students use the word gravity for Earth's pull on objects. They want evidence about the direction of that pull, not just a guess about where things will land.

First, the class tests a foam ball, a rubber eraser, and a ball of crumpled paper. One student holds each object 20 centimeters above the tray. The student opens their fingers without throwing or pushing the object. The class changes which object is released. It keeps the release height, tray position, and still-air conditions the same. Students watch the path and record where each object lands. They repeat each release four times. In all twelve trials, the object moves down and reaches the tray directly below the release spot. None stays at the release height.

Next, the class places the eraser on a stiff card held above the tray. While the card stays in place, the eraser does not move down. A student then moves the card out from under the eraser without pushing the eraser downward. The eraser moves down into the tray. It stops when it reaches the tray's bottom. Students record both parts of the test: what happened with the card in place and what happened after the card was removed.

Finally, the teacher turns on a small classroom fan. A released piece of crumpled paper moves sideways as well as downward. It lands farther to one side than it did in still air. The class records both directions of motion instead of recording only the sideways motion. Students now have observations from releases, a support test, and moving air. They will use this evidence with a model of Earth to explain their predictions.