Henry Derr, chemistry professor at LCCC (Laramie County Community College), and I made these glass teardrops. We used 3/16 inch diameter soda-lime glass rod, and melted the end of it with a propane/oxygen torch (MAPP gas might work just as well). We held the melting end of the rod pointing slightly downward a foot or so above a large beaker with 6 or 8 inches of water in it. The molten droplet of glass clings to the end of the rod until it is about 3/8 inch in diameter, and then falls into the beaker.

The droplets freeze rapidly as they hit the water. Many of them shatter, but some produce solid teardrop shapes with tails. The broken pieces in the beaker are not sharp, but blocky in shape. Nevertheless, be careful fishing out the good droplets. Oh, they'll make a loud popping noise as they reach the water, and maybe even hit the side of the beaker.

The interesting patterns shown in my photograph are the stress fields frozen in the drops. The outer part of the drop freezes rapidly as it hits the water. The inner part cools more slowly and contracts. This places the entire outer surface of the drop in strong compression and hardens it so much that you can hit it with a hammer on a concrete slab without breaking it. Yet, if you just snap off its tail with your fingers it will explode into blocky little chunks of glass. Take care if you decide to break one. Wear safety glasses and gloves.

In the near future I may write about how to analyze the pattern of stress in the photo. For now, they just make a wonderfully strange picture.