Glass Bead on a Wire Lesson

Glass Bead at a glance

Background

Imagine turning a simple white powder from your kitchen into a shiny, glassy bead using just the heat from a flame! In this lesson, students will explore how borax, commonly found in laundry detergent, transforms from a crystalline material into glass.

Borax starts as large crystals but is available in stores as a fine powder with an orderly atomic structure. When heated to a high temperature, the water in the crystals evaporates, causing the atoms' arrangement to break down, leaving behind a transparent, glassy solid. This transformation allows students to witness the shift from a crystalline structure to an amorphous solid, which has no long-range atomic order.

Using a Bunsen burner or propane torch, students will heat powdered borax, observing its transformation into a glassy bead. They'll also learn how metal ions can enter the glassy structure, creating colorful beads based on the flame's part used. By the lesson's end, students will understand how heating can change material properties, a process vital in glassmaking.

Lesson Objective

Students will explore the transformation of crystalline borax into an amorphous glass by heating it and observing how the addition of metal ions creates colored glass beads. This experiment demonstrates the process of glass formation and the influence of different metal ions on glass coloration.

Experiment Description

Students will heat copper and nichrome wires in a Bunsen burner flame, dip them in powdered borax, and then observe the formation of glass beads on the wire. The color of the beads will vary depending on the metal ions present and the heating conditions.

Materials List

Copper wire (18-gauge)
Nichrome wire (20-gauge)
Powdered borax
Bunsen burners
Needle nose pliers or tweezers
Heat-resistant containers (e.g., ceramic bowls)

Safety Precautions

Wear safety glasses during the experiment and use pliers or tweezers to handle hot wires.
Avoid direct skin contact with powdered borax, and do not flick the wire to prevent glass beads from falling off.

The Experiment

1. Cut two pieces of copper wire and two pieces of nichrome wire, each about 12 cm long.

2. Place a small amount of borax (about a teaspoon) in a watch glass or other heat-resistant container.

3. Use the pliers to form a small loop on the end of each wire. The loop should be slightly larger than the eraser on the end of a pencil. Wire with an appropriate size loop formed at one end

4. Using a Bunsen burner, heat the loop at the end of one of the copper wires until it gets red hot. Be sure to use the pliers to hold the wire while heating. Be sure that the Bunsen burner is turned up high – you should be able to clearly see the reducing region and oxidizing region of the flame.

5. Dip the hot end of the wire into the borax.

6. Carefully heat the borax on the wire until it is melted and the loop fills in by placing the loop in the purple-colored outer flame (also called the oxidizing region of the flame). When the bead has a transparent color with very few air bubbles, you may add more borax if you would like to make a larger bead.

7. Repeat steps these steps with the other copper wire, but hold the borax-covered wire loop in the blue inner flame. Keep it red hot for 10 to 15 seconds, then cool it for 10 seconds by lowering it into the darker blue flame just above the Bunsen. The color produced is temperature dependent.