Units

Glass: A Unit Study

Glass: A Unit Study

On May 16th in 1861, Irving Wightman Colburn was born. Colburn invented the method of inexpensively making large, continuous sheets of glass which has revolutionized the glass industry.

The Properties and Uses of Glass

Glass is among the most popular materials for building and decorating. This amazing, primarily sand-based compound is normally clear, but can be colored by adding impurities. There are many various types of glass with a staggering array of different properties. Some types are water soluble, and are used to coat eggs, and in laundry detergent to coat the inside of washing machines. Others darken when exposed to light and turn clear again in the dark, properties that are good for some types of eyeglasses. Some are shatter-resistant for car windows. Some glass is drawn into fibers and then bound together to become stronger than wood, making it valuable for many building projects. Others contain lead which, when put under pressure, “takes” to and bonds to copper, making it premier for the air-tight wire lead seals in incandescent lights and, many years ago, in vacuum tubes.

Plate Glass History

Perhaps the most amazing type of glass, however, is plate glass which finds its use in windows. Making a smooth glass surface is not easy, but techniques whereby massive plates of high quality smooth glass can be readily produced have been invented.

Glass: A Unit StudyFor the longest time, plate glass was produced by creating large glass cylinders, which were polished and cut into rectangular pieces. This method was labor intensive and utterly incapable of being mass-produced. In fact, plate glass was so rare that in the early days of the United States any more than ten panes of glass per house was subject to a luxury tax. This “luxurious” glass, which was of poor quality, full of bubbles and streaks, was considered valuable enough that when moving, families usually took all of the windows with them and the house sold, “without glass”!  A fairly common alternative at that time, if the windows simply had to be glass and not oiled paper or simply holes in the wall, was to take old bottles and line them up in a nice row and then frame them in. Old green bottles, being of blown glass, were easier to manufacture and come by, but were of even poorer quality glass than the windows.

How Plate Glass is Made

That there was a way to make better plate glass is obvious, as the quantity of plate glass in buildings testifies, nor is it susceptible to luxury taxes anymore — all made possible by Irving Colburn’s glass production method. While Colburn’s company did go bankrupt, the method survived and it is called “rolling.”

In this process, the glass is taken out of a vat in which it is melted, and rolled upward by metal rollers, squeezing it into a sheet and flattening it. Once the glass reaches the top of the massive shaft of rollers, it is conveyered away. One of the main disadvantages of this technique is that the glass has to be polished to be smooth.

However, a way to produce plate glass without polishing was invented in 1959. This now-common technique floats rolled, heated glass on top of liquid tin. As it is suspended by the tin, it naturally flows out into a perfectly smooth surface, creating premier plate glass.

The floating method revolutionized the glass industry, accounting for glass skyscrapers of highly polished plate glass and testified by the fact that when buying a house, you would be appalled if it was sold the good old-fashioned way — “without glass!”

 

Suggestions
  • Go on a quick explore of your home.  Make a list of things you find that are made out of glass.
  • Watch the video below.  Make a list of the ingredients that are used to make glass.  See what you can find out about each one.
  • How does lightning make glass?  See what you can find out about fulgurites.  If you live near the mountains, go on a fulgurite expedition!

 

Further Investigation

How Plate Glass is Made
(You may want to install an ad blocker before viewing.)

 

Today in Technology History: September 4
Biography of Irving W. Colburn

Syrup Off the Roller
Background on Irving W. Colburn, his glass production process, experimental factory, bankruptcy, and ultimate sale to Toledo Glass Company.

Sodium Silicates
Scroll down for uses of waterglass.

Raise More Poultry
Old ad that explains how to use waterglass to preserve eggs.

How Fiberglass Is Made
Background on this versatile material.

What Are Fulgurites and Where Can They Be Found?
Background on lightning glass.

 

Activities

How Everyday Things Are Made: Glass
Online resource from Stanford featuring a PPG video explaining the glass manufacturing process.  (Choose Products 2 tab on the left, and Glass under the Materials heading.)

Experiment 11: Glass Molding
Experiment from Laboratory Manual in General Science by Bertha May Clark

Flexible “Glass” Sculpture
Dick Blick activity using an acrylic paint that resembles hot blown glass.

G is for [Sugar] Glass
Make a sheet of edible glass.

 

Books

Pittsburgh Plate Glass Company
Illustrated small book in the public domain that explains how glass was made using the rolling process.

The Story of Glass {Free eBook}The Story of Glass by Sara Ware Bassett
Living book that teaches how glass is made, and more!

Window Glass in the Making
Another public domain title from the American Window Glass Company that covers uses, quality, origin, composition, and other interesting information.  Subtitled, “An Art, A Craft, A Business,” this is a nicely illustrated and easy read.

 

Unit Studies & Lesson Plans

Glass and Glass Blowing
A Dynamic2Moms.com unit with lapbook pages that covers the history of glass, the chemical makeup of glass, and glass blowing.

 

Printables & Notebooking Pages

Glass Notebooking Pages
Simple notebooking pages for copywork, narrations, or wrapping up.