New Substance or Not? A Makerspace Property Log

Four Projects, One Question

1The makerspace at the Riverside Public Library is open to teens every Saturday afternoon, with adult volunteers on hand to help. This month, four teen makers kept a property log for their projects. They wanted to know which projects only changed how a material looked and which ones produced a new substance through a chemical reaction.

2Scientists identify a pure substance by its characteristic properties, such as its density, its melting point and whether it dissolves in water. These properties stay the same for a substance no matter how much of it there is or what shape it has. The makers measured density themselves by finding each sample's mass and volume. A materials lab at the local community college measured the melting points for them.

3Project 1: Nadia fed scraps of white PLA plastic into a melter. An adult poured the melted plastic into a mold, and it cooled into a phone stand.

4Project 2: To power a small cart, Leo mixed baking soda with vinegar in a bottle. Gas bubbled out quickly through a nozzle and pushed the cart forward. Afterward, the leftover liquid sat in a dish until the water evaporated, leaving white crystals. When Leo added a few drops of vinegar to the crystals, nothing fizzed. A sample of the crystals had a mass of 7.65 g and a volume of 5.0 cm³.

5Project 3: For a homemade water-quality sensor, Priya dissolved rock salt in warm water to make a test solution. She left some of the solution in a dish, and clear crystals formed as the water evaporated.

6Project 4: While building a magnet sorter, Owen left a pad of steel wool in a damp dish on a windowsill for a week. The gray pad turned into a crumbly red-brown powder. A magnet that lifted the steel wool easily barely moved the powder.