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What is Glass Made of? [Step by Step Guide]

From water bottles to kitchen jars, window panels to furniture surfaces, a glass mirror or a glass light bulb, even the cabin partitions in the offices, glass is used everywhere. 

Have you ever thought about how glass is made? What material is needed during the glass-making process? How is it made naturally?

If not, you’ll find all the info related to the glass making process in this post. So, kill your curiosity and read it till the end.

What is glass made of? Glass is basically made of sand(silica or silicon dioxide). It is heated to a very high temperature in a furnace then cooled rapidly. The cooled molten sand takes the form of an amorphous solid. It is how a simple glass is made. Soda-lime silica glass is made by heating a mixture of soda ash, lime, and silica at a very high temperature and then cooled too quickly.

If you think that glass is a modern invention, you’re wrong. It was first made in 3,600 BC in Mesopotamia. Some archaeologists believe that the first origin of glass was in coastal north Syria, Mesopotamia, or Egypt. It was first used as jewellery and later as vessels. Nowadays, several high-tech industries are manufacturing multipurpose glass.

Let’s learn more about glass.

What Is Glass? 

For those who don’t know what is glass, just focus here. It is a hard, solid, and transparent inorganic material. Mainly, it is made from silica. It is made in different shapes. It has been used for practical and decorative purposes since ancient times. It is made from molten sand that is cooled rapidly to prevent crystal formation. 

Glass is one of the most popular materials of our daily use. It is chemically non-reactive to things that you put inside it. Moreover, it is the least expensive to manufacture. The molten silica can be transformed into different shapes. Once it is set, it develops reasonable heat resistance properties.

What Are The 3 Main Ingredients Of Glass?

The three main ingredients of glass are sand (Silicone dioxide), limestone (calcium carbonate), and soda ash (sodium carbonate).  

The ordinary sand is made of silicon dioxide. During the glass-manufacturing process, It is heated at high temperatures along with soda ash, recycled glass waste, and limestone in a furnace until it turns into molten sand. Soda ash helps to lower the melting point of sand, but it induces liquid soluble property in the mixture. To prevent liquid solubility of the glass, limestone is added to the mixture.

Finally, we get the soda-lime-silica glass, which is the type of glass that we normally use.

How Glass Is Made Naturally

You’ll be surprised to know that glass is not only man-made material but can also be formed naturally. In nature, glass can be formed in different ways.

  • Fulgurite glass: When lightning strikes desert or beach sands, the molten silica cools rapidly. As a result, it attains a glassy shape in the form of glassy rock. Fulgurite is an example of such glass. 
  • Volcanic glass: Similarly, during volcanic eruptions, the molten rocks erupt and then cool down quickly, forming a natural glass-like structure. Obsidian glass is an example of volcanic glass. Its texture is lustrous, rich in silica, and strong as compared to the window glass.
how glass is made
  • Tektites and Libyan desert glass: Million years ago, the force and heat of meteorites have created natural glass in the affected area. Tektites and Libyan desert glass are examples of such glass.
  • Silica glass: The skeletons of some microscopic marine alga and sea sponges contain silica. It is a type of naturally occurring glass.

How Glass is Made

The step-by-step procedure of glass manufacturing on a commercial level is mentioned below. So, have a look to know more:

Step 1 – Silica is heated at high temperature: Sand is also known as silica consists of tiny quartz crystals. For manufacturing a simple glass, it is heated at a high temperature of 1700°C (3090°F) in a heating furnace. It is then cooled rapidly. As a result, it loses its crystalline form and attains a state between liquid and solid on a molecular level. This state is known as amorphous solid. In this state, some molecules have a crystalline shape as in solids and randomness as in liquids.

For the manufacturing of soda-lime glass, all the three ingredients including soda ash, silica, and limestone are mixed in the right proportions in a furnace at about 1700 degrees celsius.

The molten mixture is added to moulds to transform into glasses and other containers. 

Skilful workers make unusual glass shapes by blowing air into a lump of molten glass. This lump is wrapped around one end of the pipe and rotated over the heat. From the open end of the pipe, the air is blown into the lump, and it fills with air like a balloon. It is then turned over and over to get the desired shape of the glass.

Step 2 Molten Mixture is passed over a molten tin surface: For manufacturing flat sheets of glass, the molten sand mixture is allowed to float over a molten tin surface. The temperature of the molten mix is 1700 degrees celsius while passing over a vat of molten tin metal. This temperature is reduced to half while leaving the tin surface. The molten mixture is transformed into a solid ribbon. At this point, some metal oxides are mixed with it to add colour.

Step 3 – Hard or soft coating applied: For making reflective glass, the surface of the solid ribbon is treated with a hard or soft coating at high temperatures.

Step 4 -The internal stresses in glass are removed: Annealing is done to give a hardened texture to the glass. An annealed glass is easy to cut.

Step 5 – Quality proof tests are done: Advanced technology is used to check if the glass has any unmelted sand grains, air bubbles, or stresses. The glass that has passed the test is ready to dispatch.

Step 6_Final packing: To cut the square sheets of glass, diamond cutters are used. 

Uses Of Glass

Glass is used almost everywhere, from your kitchen to bathroom, in vehicles, home interiors, and exteriors, in short, there are many uses of glass in our daily life. Some of these uses are mentioned below:

Kitchenwares: Heatproof or oven-proof glass is mostly used in kitchens for baking. The lids of different utensils are made of heat-proof glass or borosilicate glass. This type of glass is manufactured by adding boron oxide to the molten sand mixture. Normally, the type of glass that we see everywhere is soda-lime glass. Glass-ceramic cooktops are used in most kitchens. Even the doors of the microwave oven consist of glass that prevents the emission of microwaves from it.

Buildings and Interiors: Window panes are made of reflective glass that reflects sunlight to keep our homes cool. The LCD of laptops, TVs. and even LED of your smartphone is made of glass. The bathroom mirrors that we use to improve our looks are also made of glass.

Vehicles: The windshields of cars and other vehicles are made of toughened glass. It is made by cooling the molten sand mixture instantly which strengthens the glass. The bulletproof glass of cash-carrying vehicles is manufactured by blending multiple layers of glass and plastic.

Related Questions

What is Glass Made of Chemically?

The main ingredient for glass composition is silica (Silicon dioxide). Soda-lime glass is chemically made of 73% silica, 15% sodium oxide, 7%calcium oxide, and 4% magnesium oxide.

Can Glass Be Made at Home?

You should not try to make glass at home as it requires heating silica at extremely high temperatures that are difficult to achieve at home. Moreover, it can be dangerous.

Conclusion

Finally, we concluded that glass is a highly adaptable material. From soda ash glass to complex glass, modern technology is making discoveries of different forms of glass. 

On the commercial level, glass is strengthened by ion-exchange methods. It is a clean, clear, cheap, and unreactive material that is widely used in our daily life. Image life without a glass, how it would look like? No doubt, it has become a crucial necessity of the modern age.