Orchard Gate Workshop: Mystery Materials

An Orchard Workshop Investigation

At an apple farm, workers are repairing a gate beside the orchard. A box in the workshop holds unmarked pieces left from earlier repairs. Before sorting the pieces into storage bins, a visiting science club investigates four mystery samples, M, N, P, and Q. Each sample is made of iron, aluminum, plastic, or pine. The club also has a labeled reference sample of each material.

An adult checks that every piece is clean, dry, and free of sharp edges. None has paint or another covering. The students first record each piece's color and look closely for grain, the lines often visible in wood. They measure mass with a digital balance and record grams. The pieces have different sizes and shapes. A ruler is available if they want to measure length.

Next, they test magnetic attraction. They use the same magnet and bring it close to each sample in the same way. They record whether the magnet pulls the sample. Between tests, they move other objects away so that nearby metal does not affect the observations. They test the labeled references before testing the mystery pieces.

Finally, the club tests electrical conduction. An adult provides a low-voltage battery circuit with a small lamp and a gap between two wires. Students place each sample across the gap, with both wire ends touching clean surfaces. They keep the battery, lamp, and wires the same. A glowing lamp means electricity passes through the sample in this circuit. They never use a wall outlet.

Before each mystery test, the students check that the lamp lights when the wires touch each other. They repeat each completed magnetic and electrical test three times and get the same result each time. Their records appear below. The electrical test for M has not yet been done. The club will use the records to label the mystery pieces and explain the evidence behind each choice.