HW # 39- Watch “Microscope” video (link on the website)http://www.youtube.com/watch?v=X-w98KA8UqU

Warm up

Why would we want to use a microscope to see things? When would it be better to use a telescope or binoculars?

Week 12, Day One

Warm up Response

Homework Response/Check

Goals for Today• Microscopes

• KWL• History

The History of the Microscope

History of the Microscope

A long time ago (around the 1st century) someone picked up a piece of crystal which was thicker in the middle…looked through it and discovered it made things look LARGER.

History of the Microscope

• That piece of crystal was called a “magnifying glass” and then later was called a lens because it was shaped like a lentil seed.

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History of the Microscope

• Then, in the 13th century (1200’s) an Italian inventor made the first eye glasses, allowing the wearer to have magnification. His name was Salvino D’Armate. Eye glasses were also called spectacles.

History of the Microscope• The earliest forms of

magnification were magnifying glasses, usually between 6x to 10x, and were used for looking at tiny insects. These excited general wonder when used to view fleas or tiny creeping things and so were dubbed "flea glasses."

History of the Microscope

• In the 1590’s two Dutch eye glass makers, Zacharias Jensen and his father Hans, started experimenting with lenses…

History of the Microscope

• The Jansens put several lenses in a tube and made a very important discovery…the object at the end of the tube appeared MUCH larger than when it was under a plain magnifying lens!

History of the Microscope

• In the late 1600’s, Anton Van Leeuwenhoek became the first person to make and use a real microscope.

History of the Microscope

• Anton Van Leeuwenhoek achieved even greater success than his peers by making superior lenses. He learned how to grind and polish lenses. He arranged them in a lens tube and achieved a magnification of 270x – others were lucky to achieve 50x with their microscopes!

History of the Microscope• Anton Van Leeuwenhoek was the first to see bacteria, yeast, and life found

in a drop of pond water. He found extraordinary things using his microscope throughout his lifetime.

• Here is a look at a virtual drop of pond water:

Pond Water

History of the Microscope

• An English scientist named Robert Hooke further developed Anton Van Leewenhoek’s work and in 1665 Hooke discovered cells.

History of the Microscope

• Robert Hooke developed a primitive compound microscope

History of the Microscope

• Robert Hooke’s Micrographia was known for stunning illustrations he did himself of the microscopic world.

History of the Microscope:Illustrations from Micrographia

History of the Microscope:Robert Hooke’s Cork Cells

History of the Microscope• Despite these great discoveries, microscopes

did not change much over the next 200 years.

History of the Microscope• In the 1850’s a German engineer named Carl

Zeiss began making adjustments to the microscopes he was manufacturing, making them even better.

History of the Microscope• With the

advancement of technology and improved optics, the compound light microscope came into being.

Other types of microscopes: Electron Microscopes

• Uses a beam of electrons to illuminate and magnify a specimen

• Very expensive • Huge

Other types of microscopes: Electron Microscope Images

Other types of microscopes: Electron Microscope Images – Human Hair 800x