Microscopes by Isobel Woosnam

(micro means ‘small’ and scope means ‘to see’ = to see small things)

A ‘light microscope’ uses two sets of lenses to make things seem much bigger than they really are… sometimes hundreds or thousands of times bigger. When things are made to look bigger than they are we say they have been MAGNIFIED.

A ‘compound microscope’ magnifies things in two stages. Light from a mirror reflects up through the objects, which has to be very thin for the light to pass through. The light passes into a strong, powerful lens called the objective lens. This is the first time the object is magnified. There is also an eye piece lens which you look through, this gives the second magnification. This lens is a bit like a small magnifying glass.

(Image from http://www.microscope-microscope.org/basic/microscope-parts.htm)

There are also modern microscopes called electron microscopes that can magnify upto 300,000 times. What can be seen with an electron microscope is clearer than using a compound microscope.

So who invented the microscope?

It wasn’t just one invention or one person, it was developed over a period of time…

The first basic microscope was not made until the late 1300’s. Two lenses were placed at opposite ends of a tube. This simple magnifying tube was the start of the modern microscope.

More than 400 years ago in Holland, there was a man who made a living by grinding glass to make lenses for spectacles. His name was Zacharias Jansenn. He noticed that some of his lenses made things look bigger and when he put two lenses together it made things look a lot bigger. So in about 1595 Jansenn made the first microscope, Jansenn’s microscope was made of three tubes inside each other – like a telescope – with lenses inside. It had an eye- piece lens and...

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.... In 1729, Chester Moore Hall developed a special lens called the achromatic lens and the, the quality of microscopes improved because the light rays were more controlled and focused.

image taken from http://zeiss-campus.magnet.fsu.edu/articles/basics/historical.html

Bibliography http://www.andrewlost.com/microscope_inventors_k3.htm http://www.kidsbiology.com/biology_basics/cells_tissues_organs/cell_history_discovery3.php http://www.history-of-the-microscope.org/hans-and-zacharias-jansen-microscope-history.php http://www.history-of-the-microscope.org/history-of-the-microscope-who-invented-the-microscope.php http://www.microscopemaster.com/history-of-the-microscope.html http://www.microscope-microscope.org/basic/microscope-parts.htm http://zeiss-campus.magnet.fsu.edu/articles/basics/historical.html Science Encyclopedia Parker,S (Editor) Parragon 2000 page132