Glass Spheres (medium)

These pea-sized transparent glass spheres are made from soda-lime glass, familiar to us as the glass used for drinking vessels, bottles and windows. It is reusable and recyclable. In science, glass has a much broader definition than this transparent substance, referring to any solid which has a non-crystalline, or amorphous inner structure. It is a myth that glass is always liquid, it only really becomes a liquid when heated at 550°C, and is fully liquid at around 1000°C.

Glass spheres are perhaps most familiar to us a marbles, but smaller, industrially produced glass spheres like this are known as ballotini, from the Italian for 'small balls'. Their main applications include reflective filler for road-marking paint, and abrasives for shot blasting and metal polishing. However, they can also be engineered into perfectly regular spheres to be used as spacers in adhesives, to ensure a perfectly uniform thickness of bond, or for use as special bearings for oil drilling mechanics. Glass is a particularly non-reactive and non-degradable material which is cheap to produce, making it a versatile industrial material.