Sylvania light bulb glass strength demonstration

Same as above; Sylvania's Beverly, MA plant was the source of the freshly-made bulbs. ## Figures referenced

The story I know is, my old thesis advisor Bob Rose lives up on the North Shore. Sylvania had a glass light bulb manufacturing plant up there in Beverly. He used to lecture 3.091 back in the days when I was a student, and he would stop and get freshly made light bulbs on the way in before his lecture. He would take the light bulbs in 10-250 and throw them across the room, and they'd bounce. They wouldn't shatter, because they were freshly made. They did not have surface imperfections that caused them to fracture.

Tom's old thesis advisor (3.091 lecturer, North Shore resident) would stop at the Sylvania lightbulb plant in Danvers to pick up freshly-blown bulbs that could be bounced across a classroom. Used to teach that brittle materials are flaw-controlled — freshly-made glass with no surface imperfections is extraordinarily strong.

When I talk about glass being strong when it's freshly made: glass has no imperfections on the surface if it's made properly. And it's the imperfections on the surface of a brittle material that weaken it. My old thesis advisor used to teach 3.091, and he still lives up on the North Shore. They had a Sylvania lightbulb plant up there in Danvers, and he used to stop in the morning before his lecture and get freshly made lightbulbs — fresh-blown glass — and bring them in for his 10 o'clock lecture. He could throw them across the room and they would bounce, because they were freshly made. The glass had not been attacked by the humidity in the air. After a few days you throw it across the room and it'll shatter just like any lightbulb you know of. But freshly made glass, before it starts to get etched by the moisture in the air — it actually does on a microscopic scale, but it's so brittle these submicron imperfections destroy its strength.