A little bit of history - pencil sharpeners
In this issue we continue our series on the history of frequently used pieces of classroom equipment. Following our article on the history of pencils in Issue 55, we thought it would be appropriate to look at the history of the pencil sharpener.
Despite the fact that pencils have been around in various forms since the 16th century, it was over 300 years before someone came up with something people could use to sharpen them. Before pencil sharpeners, a pencil was sharpened using a knife (whittling). This was often a bit of a chore and rather a hit and miss affair that didn’t always give the desired shape or even a sharp pencil tip. Then in 1828 the first pencil sharpener was invented. It didn’t resemble the pencil sharpeners we have today. The sharpener had small metal files set at 90º in a block of wood. These files scraped and ground the edges of the pencil’s tip. The inventor was a Frenchman named Bernard Lassimore. Unfortunately it wasn’t much faster than whittling and so it didn’t catch on.
Twenty-six years later another Frenchman, Therry des Estwaux, improved on the original design and came up with the first sharpener that worked by twisting the pencil inside a conical shaped device.
In 1851, an American, Walter K Foster, patented the first American sharpener which was an improved version of the one invented by Therry des Estwaux. The advantage of this version was that it could easily be mass produced. Numerous variations of the conical shaped sharpener developed after this as there were frequent demands for improvements in design. Inventors and companies took up the challenge of supplying offices, schools and eventually homes with efficient machines to sharpen pencils. This began as a result of the mass production of wood-cased lead pencils in the late 1870s. Some of these were handheld, others could be stood on a flat surface with a winding device, but all these variations had one flaw. They were quite bulky and when using them, the user had to hold the sharpener steady and turn the pencil or hold the pencil still and turn the sharpener. These methods often resulted in a broken lead.
The Eagle's new pencil sharpener
In 1896 the AB Dick Planetary Pencil Pointer arrived. It used files on discs which revolved as they went around the pencil’s tip. The user had to insert the pencil into what was known as the ‘chuck’ which was mounted in a sliding carriage. They would then slide the carriage along a horizontal wooden shaft. The pencil rubbed on the files and rotated, the result was a sharpened pencil!
Not long after this came the electric pencil sharpener. It was developed in the early 1900s but didn’t become commercially viable until the 1940s. These sharpeners had a huge advantage over all previous types because the user could simply insert the pencil and moments later take it out and it was sharp – like magic!
Pencil sharpeners now come in a wide variety of colours and shapes, including those powered by battery, mains electricity and hand. Some sharpeners have a case around them to collect the shavings which can then be emptied. Most have blades inside the sharpener which sharpen the wood of the pencil and therefore the tip and the shavings come out of a slot along the edge of the blade.
Today some specialised types of pencils, such as the flat ones used by carpenters, are still often sharpened with a knife.
Did you know…
The Reverend Paul Johnson, a World War Two veteran started collecting pencil sharpeners after his wife gave him some as a gift in the late 1980s. He kept his collection in a small shed outside his home in south east Ohio, US. Altogether he had 3 400 and the oldest was 105 years old! He died in 2011 and shortly after his death tourism officials in Logan, Ohio, put them on display in its welcome centre.
Information sourced from:
Now for some mathematics!
You could make a collection of all the sharpeners in your classroom. This could lead to activities such as counting efficiently and making arrays. You could ask the children to suggest ways to sort them, for example colour, size and the material that they are made from. Use a Carroll or Venn diagram to answer questions, the questions could include how many blue sharpeners do we have with two holes? Or something similar involving sorting two criteria.
They could estimate, measure and compare the diameters of the pencil holes and order these in ascending or descending order.
You could ask the children to research the different pencil sharpeners available on the internet, for example, on Google. How many have they seen in use at school or at home? Do they have one that is similar to any that they can see? What 3D and 2D shapes can they see in the different sharpeners? This would be a good opportunity to rehearse properties of shape. From a selection of 12 sharpeners (real or from the pictures), you could ask questions that involve ratio and proportion, such as, what is the ratio of cylindrical shapes to cuboid, what proportion are neither?
They could choose around 10 sharpeners of different prices and plot these prices on a number line. They could then find the differences between pairs of prices using a counting on strategy. They could find the total cost of buying several of them. You could give them an amount of money to spend on two or more sharpeners. They could then work out how much they will have left after buying them.
You could print out copies of a selection of pencil sharpeners. If the children have two copies, they could cut the sharpeners out and make a symmetrical pattern with one line of symmetry. If they have four copies, they could make a symmetrical pattern in the four quadrants.
The children could also sort the pictures according to criteria that they make up, for example, shape.
'Pencil sharpener 3'
They could draw around their own pencil sharpener and then rotate it for 45º or 90º to make a pattern that shows rotational symmetry. What shape was their original drawing? What shape or shapes can they see in their rotation? Can they tessellate their sharpener? If so, they can make a design in the style of MC Escher.
If you have some spare lead and coloured pencils the children could sharpen them and collect the shavings. They could then draw some shapes and decorate them, using the shavings, to make a collage which should have a hint of colour.
You could ask the children to time each other as they sharpen pencils using a stopwatch. Who is the fastest? They could make a table to show the results.
We hope that this article has inspired you to make a more mathematical use of your classroom pencil sharpeners! If there is any area of history that you would like us to make mathematical links to, please let us know.
If you've enjoyed this article, don't forget you can find all previous A little bit of history features in our archive, sorted into categories: Ancient Number Systems, History of our measurements, Famous mathematicians, and Topical history.
Page header by Nate Steiner, some rights reserved
The Eagle's new pencil sharpener by Boston Public Library, some rights reserved
Pencil Sharpener 3 by Andrew Kelsall, some rights reserved