I just learned how most glass is made today!
Float Glass is made on a bed of tin!
If you poured 1,000°C molten glass onto a bed of zinc, the metal would boil instantly, erupting in violent bubbles that would completely destroy the glass.
The remarkable engineering feat of manufacturing perfectly flawless, distortion-free windows actually relies on floating glass on a river of molten tin. To understand what other metals might theoretically work as a substitute, it helps to look at the extreme physical requirements inside a float glass plant. The molten glass pours out of the furnace at approximately 1,000°C (1,832°F) and must slowly cool to around 600°C (1,112°F) before it becomes solid enough to be lifted off the liquid bath without warping. The metal underneath must stay entirely liquid across this entire temperature spectrum. It also must be denser than the glass so the glass floats, and it must have a very low vapor pressure so it does not boil or emit gasses that would bubble up and pit the smooth glass surface.
If cost were not an object, gallium would be an excellent candidate. Gallium melts at just 30°C (86°F) and does not boil until roughly 2,400°C, giving it a massive liquid window. Indium shares similar favorable properties, boasting a high boiling point and excellent density. The fatal flaw for both gallium and indium is their scarcity; filling an industrial bath holding hundreds of tons of liquid metal with either element would bankrupt the manufacturer.
Historically, engineers also experimented with lead. Lead is dense enough to float glass and melts at 327°C. However, at 1,000°C, lead has a much higher vapor pressure than tin. The vaporized lead clouded the surface of the glass and created a highly toxic environment inside the factory.
Tin hits a rare “Goldilocks” zone in metallurgy. It melts at 232°C but does not boil until a staggering 2,602°C, meaning it produces almost no vapor at glass-pouring temperatures. It is roughly three times denser than liquid glass, relatively affordable, and easily protected from oxidation by pumping a continuous nitrogen-hydrogen atmosphere over the bath. While elements like gallium or indium could technically yield perfectly flat glass, tin remains the only practical choice for the process.
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Dolphins jumping!
Marian, Rosemary and I went kayaking this morning, I had seen a dolphin along the shore so I turned my camera on and pointed it where the dolphin had been. Then I guessed that he had gone upstream and panned the camera north. Marian had been standing up on her paddleboard.
All of a sudden I heard a big splash behind me. I thought Marian had fallen in but hit the water flat to make such a noise. I looked to my right, Marian was staring behind me with her mouth wide open! I endeavored to turn my kayak around when I heard another larger huge splash, and a third!! By the time I got turned around both Marian and Rosemary were sitting there aghast and I saw the fourth one jump right in front of me. The creek was quite narrow there so he did not have much room, but it was astounding to see it up so close!! The dolphin looked to be 10 foot long 2 feet wide and 1000 pounds. How they can jump so high I do not know.
We did not know if it was four dolphin or two, but they jumped so high out of the water, six feet at least! It was crazy! I did see the fourth one like sketched below. Right in front of me! I had fully turned around looking south when another one jumped behind me! I had no idea that in Bear Creek that they could jump so high! Their bodies curled to hit the water and disappear so quickly underneath me!!
Some bugs have been hard at work. Not my place thankfully! They ate all the soft parts of this board!
Their larva wiggling:
This afternoon (5-1-2026) we had a shower, an half inch fell in about 15 minutes! We needed it!
A fun start to the month, a momma and baby manatee!
I had better pictures and movies on my phone, but when I “moved” them to the computer they disappeared! A first like that.
