1. What are the parts of the microscope?

2. What’s the total magnification?
Eyepiece
Objective lens
Total Magnification
10x
40x 5x
20x

3. A little microscope history…
During the 1st century AD (year 100), glass had been invented and the Romans were looking through the glass and testing it. They experimented with different shapes of clear glass and one of their samples was thick in the middle and thin on the edges. They discovered that if you held one of these “lenses” over an object, the object would look larger.

4. Sometime about the year 1590, two Dutch spectacle makers, Zaccharias Janssen and his father Hans started experimenting with these lenses. They put several lenses in a tube and made a very important discovery. The object near the end of the tube appeared to be greatly enlarged, much larger than any simple magnifying glass could achieve by itself! They had just invented the compound microscope (which is a microscope that uses two or more lenses). 

5. Discovery of Cells

6. We haven’t always known about cells Because they are so small, cells weren’t discovered until microscopes were invented in the mid-1600s

7. Important people: Robert Hooke – 1st person to describe cells
In 1665 he built a microscope
British scientist

8. Robert Hooke – looked at cork cells
He called each of the little boxes “cells”

9. Important people:
Anton van Leeuwenhoek – looked at bacteria and blood cells.
Dutch fabric store owner in 1673

10. Important people:
Matthias Schleiden – said all plants are made of cells.
German botanist in 1838

11. Important people:
Theodor Schwann – said all animal tissues are made of cells.
German scientist that studied animals

12. Important people:
Rudolf Virchow – said all cells could only come from other cells.
German doctor in 1858

13. Remembering the 5 Scientists
Think of a piece of cork on a hook
Robert Hooke
Anton van Leeuwenhoek
Matthias Schleiden
Theodor Schwann
Rudolf Virchow
Think of a “blood van” leaving
Think of a slide – it’s green because plants are green
A swan is an animal – he looked at animal cells
Think of Rudolph the reindeer making copies of himself

14. The Cell Theory
The ideas of Schleiden, Schwann, and Virchow make up what is now called the cell theory.

15. The Cell Theory
1. All organisms are made of one or more cells 2. The cell is the basic unit of all living things 3. All cells come from other cells

16. Spontaneous Generation
States that living organisms are created from non-living matter
This theory was believed back in Aristotle’s time (4th Century BC)

17. Spontaneous Generation Cont.
It was common “knowledge” that simple organisms like worms, beetles, frogs, and salamanders could come from dust, mud, etc., and food left out, quickly “swarmed” with life.

18. Examples
Observation: Every year in the spring, the Nile River flooded areas of Egypt along the river, leaving behind nutrient-rich mud that enabled the people to grow that year’s crop of food. However, along with the muddy soil, large numbers of frogs appeared that weren’t around in drier times.
Conclusion: It was perfectly obvious to people back then that muddy soil gave rise to the frogs

19. Observation: In many parts of Europe, medieval farmers stored grain in barns with thatched roofs (like Shakespeare’s house). As a roof aged, it was not uncommon for it to start leaking. This could lead to spoiled or moldy grain, and of course there were lots of mice around.
Conclusion: It was obvious to them that the mice came from the moldy grain.

20. Observation: If meat was left out usually over time it would spoil and maggots would begin to grow and develop. Many people who believed in spontaneous generation thought that raw meat produced maggots.
Conclusion: Therefore, several people widely held that maggots arose spontaneously in rotting meat

21. They didn’t realize that there were flies who laid eggs which led to maggots
After testing this theory it was concluded that only flies could produce other flies!

22. Louis Pasteur
The theory of spontaneous generation was finally laid to rest in 1859 by the young French chemist, Louis Pasteur. He boiled meat broth in a flask, heated the neck of the flask in a flame until it became pliable, and bent it into the shape of an S. Air could enter the flask, but airborne microorganisms could not - they would settle by gravity in the neck.

23. Louis Pasteur Cont.
As Pasteur had expected, no microorganisms grew. When Pasteur tilted the flask so that the broth reached the lowest point in the neck, where any airborne particles would have settled, the broth rapidly became cloudy with life. Pasteur had both refuted the theory of spontaneous generation and convincingly demonstrated that microorganisms are everywhere - even in the air.

24. Louis Pasteur

25. Some book time
Pg 60-61, use the Biology book to fill out your notes on Advancing the microscope

26. Light microscopes –
Advantages –
Disadvantages -

27. Electron microscopes –
Advantages –
Disadvantages -

28. Transmission Electron Microscopes (TEM)–
Scanning Electron Microscope (SEM) –

29. Dissecting Microscope

30. Images seen using an electron microscope

31. Mosquito head Magnification: X 200
The mosquito's head is mostly eye. The eyes of most insects are compound eyes, made up of many tiny lenses. Each lens sees a slightly different picture, making up a mosaic of the object it is looking at. This type of vision is very efficient at noticing very slight motions such as another insect trying to sneak up on it

32. Magnification: X 300 Foot of a House Fly
Flies use their feet for many purposes. The claws can grab to hold on. The small hairs will adhere to smooth surfaces through surface tension. Other hairs are sensory organs, allowing flies to taste with their feet.

33. Porcupine quill
Magnification: X 50
Porcupine quills are sharp as needles. Unlike needles, quills have backwards facing barbs that catch on the skin making them difficult to extract.

34. Dentist Drill
Magnification: X 50
The dentist drill is covered with tiny diamond chips. Diamonds are the hardest substance known and will easily wear away tooth particles as the drill spins at high speeds.

35. Toilet paper
Magnification: X 500
The long, thin fibers you see here are really elongated cells of the pine tree. The trees are cut down, chipped up and pounded to separate the fibers from the rest of the tree material.

36. Staple through paper
Magnification: X 35
Common everyday items take on a new dimension at high magnification. In this photo, a staple is seen where it ripped through the fibers of a yellow sticky note paper.

37. Scratch and Sniff paper
Magnification: X 1,000
These tiny glass capsules contain a liquid scent and are glued onto paper. When the paper is scratched, some of the capsules are ruptured and the scent is released.

38. Rice Leaf
Magnification: X 750
Many grasses feel rough to the touch. A close-up of this rice leaf shows its bumpy texture.

39. Mascara Brush
Magnification: X 35
The bristles of this mascara brush are covered with dried mascara and flakes of skin.

40. Bacteria living on skin

41. Ice cream under electron microscope (showing fat globules and ice crystals)