Microscopes
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Microscopes. Write down the stuff in GREEN (minimum). Look at your hand…. One square centimeter of skin contains more than 100,000 cells. No matter how closely you look with your eyes, you won’t be able to see individual skin cells. How the heck did we figure out they were there?.

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Microscopes

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Microscopes

Microscopes

Write down the stuff in GREEN (minimum)


Look at your hand

Look at your hand…

  • One square centimeter of skin contains more than 100,000 cells.

  • No matter how closely you look with your eyes, you won’t be able to see individual skin cells.

  • How the heck did we figure out they were there?


With microscopes

With microscopes!

  • Microscope technology had to be invented before we could know that cells existed.


So who invented this technology

So who invented this technology?

  • 100a.d. Romans began “blowing glass” to make shapes.

They made glass by super-heating sand – Sweet Home Alabama story


So who invented this technology1

So who invented this technology?

  • The Romans began experimenting with this blown glass and discovered that if you looked through curved glass, it made things look bigger.


So who invented this technology2

So who invented this technology?

  • Someone also discovered that you can focus the rays of the sun with one of these special “glasses” and start a fire. These early lenses were called magnifiers or burning glasses.

A simple microscope like this one has only one lens.

Story of burning glass at mountain man rendezvous


So who invented this technology3

So who invented this technology?

  • The word lens by the way, is derived from the latin word lentil, as they were named because they resembled the shape of a lentil bean.


So who invented this technology4

So who invented this technology?

  • Around 1250 spectacle makers were producing lenses to be worn as glasses.


So who invented this technology5

So who invented this technology?

  • The early simple “microscopes” were really only magnifying glasses and had a magnification power of 6x to 10x. One thing that was very common and interesting to look at was fleas and other tiny insects. These early magnifiers were hence called “flea glasses”. 


So who invented this technology6

So who invented this technology?

  • Around 1590, a Dutch spectacle maker named Hans Janssen put several lenses in a tube, created the first compound microscope, and discovered that he could see VERY tiny things.

Two or more lenses put together make a compound microscope.


So who invented this technology7

So who invented this technology?

  • Galileo, in Italy, heard about Janssen’s new magnifier and began making refinements to his telescopes with the same ideas.

This “spyglass” was used on ships that visited Italy.


So who invented this technology8

So who invented this technology?

  • About 1660, an Englishman named Robert Hooke made a compound microscope that had alamp for lighting specimens. The light was focused onto the specimen and it could be seen in greater detail – not just the outline. He called the little rooms he saw CELLS.

A light microscope uses light to see a specimen


So who invented this technology9

So who invented this technology?

  • In about 1674, a Dutch fabric merchant named Anthony van Leeuwenhoek began fiddling with ways to see the threads of his fabrics better.


So who invented this technology10

So who invented this technology?

  • He began looking at pond water and discovered that it was ALIVE! He gave these tiny creatures the nickname “animalcules.” (write next to 1674)


So who invented this technology11

So who invented this technology?

  • Anthony also began finding interesting stuff everywhere – even in the gunk on his own teeth! He eventually made microscopes that could magnify 266 times. He also was the first to see bacteria. (Not bad for a non-scientist type!)

Leeuwenhoek sent drawings like this to the Royal Society of London


So who invented this technology12

So who invented this technology?

  • In about 1880, a German named Carl Zeiss began making REALLY good compound light microscopes, and we saw individual cells for the first time. He perfected his lenses by using Math calculations.


So who invented this technology13

So who invented this technology?

  • Even now, most good microscopes are made in Germany or Japan. The cheap ones that you can buy as part of a science kit have plastic lenses that aren’t that great.


So who invented this technology14

So who invented this technology?

  • In 1933, a German named Ernst Ruska created the first electron microscope. Transmission Electron Microscopes (TEM) send electrons through very thinly sliced specimens. They can magnify up to 500,000 times.

Organelles inside of a cell.


So who invented this technology15

So who invented this technology?

  • In 1965, Scanning Electron Microscopes were invented. These send electrons over the surface of a specimen and create images that are almost like 3-D.


So who invented this technology16

So who invented this technology?

  • In 1981, the Scanning Tunneling Microscope was invented. These measure electrons that leak from the surface of a specimen. These are the type used to “look” inside cells and cell organelles.

Silicon molecule through STM


Microscopes

Next:

Find out how to use a microscope…..


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