Why do old windows have circles in them?

In the 18th and 19th centuries, we made window panes from something called “crown glass”. You have probably seen glass blowers at work, in film if not in real life. They pick blobs of glass up on long metal tubes called a “pontil”, and then blow through this to inflate the glass and create hollow shapes.

What are bullseye windows?

oeil-de-boeuf window, also called bull’s-eye window, in architecture, a small circular or oval window, usually resembling a wheel, with glazing bars (bars framing the panes of glass) as spokes radiating outward from an empty hub, or circular centre.

What is a hopper window?

According to the Efficient Windows Collaborative, the hopper window definition includes windows with movable sashes that openinward. The hinge is on the bottom, and they make excellent windows for bathroom or basement installations. Since the windowpane tilts upward, it stops debris from blowing into your house.

Why is it called crown glass?

So called from a crown-like shape given to it in the process of blowing.

What is crown glass?

Crown glass is a type of optical glass used in lenses and other optical components. It has relatively low refractive index (≈1.52) and low dispersion (with Abbe numbers around 60). Other additives used in crown glasses include zinc oxide, phosphorus pentoxide, barium oxide, fluorite and lanthanum oxide.

What color light travels faster in Crown glass?

From the second boxed equation, we can see that the wavelengths of red light and blue light are reduced by the same factor (1/η) in a given medium. That means the red light will still have a longer wavelength after it enters the glass. Hence, red is faster in a medium.

What is quartz glass used for?

Quartz glass is used in the manufacturing of optical devices, lighting systems, refractory materials, and chemical apparatuses.

Is crown glass transparent?

The transparent disc has 100 mm in diameter and thickness of 12.5 mm and is made of homogenous optical crown glass BK7. Its lower surface is coated with a thin chromium layer with reflectance of 0.24 and its upper surface has an antireflection coating.

What color light travels faster in Crown Glass?

What does it mean to ‘get your round’ at a pub?

If you are with a group of friends and you are drinking, then ‘getting your round’ is an essential part of pub culture. If there’s a designated driver, they normally get their drinks paid for, as they don’t get to drink alcohol or at least not as much as everyone else.

What is the pub culture like in the UK?

One of the great things about the pub culture in the UK is that you can strike up a conversation with a stranger and even make new friends. It might be a passing comment about the weather or the football scores. It could also be something weightier, such as something in the news or about politics. Whatever the topic is, join in!

What is the history of pubs in England?

Alehouses, inns and taverns collectively became known as public houses and then simply as pubs around the reign of King Henry VII. A little later, in 1552, an Act was passed that required innkeepers to have a licence in order to run a pub. By 1577 it is estimated that there were some 17,000 alehouses,…

How many pubs were there in the 15th century?

By 1577 it is estimated that there were some 17,000 alehouses, 2,000 inns and 400 taverns throughout England and Wales. Taking into account the population of the period, that would equate to around one pub for every 200 persons.