The speaker discusses the importance of LED lighting and its efficiency. They mention creating a test bench for sodium and mercury lamps, demonstrating the heating process and the temperature of the glass bulbs. The speaker then delves into the history of glass, starting from the Stone Age where volcanic glass was formed. They discuss the process of creating primitive glass and how it evolved over time, with the term "glass" appearing during the times of the ancient Romans.
The speaker explains how the first transparent glass was invented in the 13th century by Venetian glassblowers who added manganese peroxide to the mixture of white sand, soda, and lime. They also talk about the soda glass, which is still used today, and the handmade Murano glass, which is considered one of the most expensive but is not as expensive as it seems due to its exclusivity and manual labor.
The speaker then moves on to the properties of different types of glass, discussing how soda glass is often used in glass bottles and window glass. They mention that due to its high expansion coefficient, soda glass doesn't tolerate temperature changes well. The speaker also talks about borosilicate glass, which was invented in the 19th century by Ashot and can withstand sudden changes in temperature.
The speaker then conducts several experiments to demonstrate the properties of different types of glass under extreme conditions, including creating plasma from aluminum in a microwave and in a beaker made of heat-resistant borosilicate glass. They also experiment with a glass made from silica gel to demonstrate its properties similar to quartz glass.
The speaker then discusses quartz glass, which can withstand extremely rare heating of more than one and a half thousand degrees Celsius without losing its properties. They explain that only the inner ampoule in metal halogen lamps is made from quartz glass, and the rest is made from heat-resistant glass melt. They then conduct experiments with quartz glass and a glass made from silica gel to demonstrate their properties.
Finally, the speaker discusses the use of quartz glass in optical instruments and fiber optic cables due to its ability to perfectly transmit infrared radiation. They also mention aluminum oxide, which has a higher melting point than quartz and can be found in sodium lamps. The speaker ends by discussing the use of different types of glass in different lamps and emphasizes the importance of choosing the right type of glass for a specific application.
Here are some key facts extracted from the text:
1. LED is a cool, economical and efficient source of lighting.
2. The author has a test bench for sodium and mercury lamps, which can create a beam of hot plasma inside a glass bulb.
3. The core of the Sun has a temperature of about 15.7 million Kelvin, while the surface temperature is about 5800 K.
4. Obsidian is a type of volcanic glass formed by rapid cooling of lava flows.
5. The term glass originated from the ancient Romans who used glassware for drinking wine.
6. Crystal is a type of pure glass invented by Venetian glassblowers in the 13th century by adding manganese peroxide to the mixture of sand, soda and lime.
7. Soda glass is the most common type of glass, consisting of sand, soda and lime. It has a high expansion coefficient and cracks easily from temperature changes.
8. Borosilicate glass is a type of heat-resistant glass invented by Ashot in the 19th century by adding boron oxide, aluminum oxide and sodium nitrate to the mixture. It has a low expansion coefficient and can withstand sudden cooling or heating better than soda glass.
9. Quartz glass is the most expensive and heat-resistant type of glass, made from melting silicon dioxide or extremely pure quartz sand. It can withstand temperatures above 1500 degrees Celsius and transmits infrared radiation well. It is used for gas-discharge lamps, optical instruments and fiber optic cables.
10. Aluminum oxide is a ceramic material that has a higher melting point than quartz glass. It is used for sodium lamps, which produce a bright yellow light from sodium vapor.