Who would have guessed you could make glass by running high voltage electricity through sand?! I was working on some experiments with a former student and he suggested that we should try to run electricity through sand to see if it would melt the sand into glass. And, believe it or not, it worked! We made glass!
What is glass made of?
Glass is made from melted and recrystallized silicon dioxide. Sand is a mixture of small pieces of weathered rock and the main component in rock (and sand) is silicon dioxide (SiO2). In fact, these two elements, silicon and oxygen, are the most abundant elements in the Earth's crust - 46.6% oxygen, 27.7% silicon. Therefore, glass is essentially recrystallized sand! I became fascinated with glass and its importance in society when I was reading "Stuff Matters" by Mark Miodownik, a book examining the materials that shape our lives - glass being one of the most important materials of our time.
How to produce high voltage to melt sand.
Microwaves use a high voltage transformer (buy one here) that takes 120 volts (in the US) and ramps it up to 2000 volts (for the microwave in our experiment). We removed the transformer from the microwave, added a cord for power and set up a contact between the housing and the ground. This high voltage electricity can cause electricity to do things you might not expect it to do. You can see in the video that a stream of electrons is jumping from one end of the transformer to the copper wire at the other end. As the electrons move through the air they create a plasma of superheated gas that can conduct electricity.
How does the high voltage melt sand into glass?
Pure quartz, a mineral composed of silicon dioxide, melts at 1,650 degC (3,002 degF). While we didn't have equipment to measure the temperature of the plasma, we can conclude that we were reaching temperatures at or above 1,650 degC because the sand melted into a rod of glass.
How to make glass from high voltage and sand
Transformer: To see how Quinn, my collaborator for this project, made the high voltage transformer, refer to the video above (CAUTION - high voltage is extremely dangerous - do not attempt to remove without assistance from a qualified professional)
Start with the positive lead attached to a nail inserted in the sand. Be sure the ground wire is at least 12 inches from your hand on a non-conductive rod. Plug in transformer.
Make a connection between the positive and ground inside the sand. Slowly pull the two apart, allowing the electrical arc to remain intact. Continue to pull apart.
When the arc 'breaks', turn off power and allow to cool.
Remove the glass fulgerite and enjoy! (Or skip all the steps above, avoid being killed by electricity, and click here to buy a fulgerite)