Introduction to Microscopes!

1. Introduction to Microscopes! Now Seeing IS Believing!

2. A Brief History

3. Simple Glass Magnifiers • More than 500 years ago. • In 1600s, this “simple microscope” allowed scientists to see cells and bacteria • Problem: not enough magnification

4. First Compound Microscope • Developed at the beginning of the 1600's, by the Janssen brothers and Galileo • Problem: images were blurred and had colored halos

7. Simple Compound Microscope • Invented in 1660s • Problem: all images had red or blue “halos” around them

11. Even better! • 1700 and 1800s – great improvement in microscopes • Usually made of brass (expensive) • Had a tripod for support

14. Modern Compound Microscope • Definition of a Compound Microscope : an instrument for magnifying small objects, consisting of a lens of short focal length for forming an image that is further magnified by a second lens of longer focal length Compare

16. Fancy! • Better images • More magnification • Better lighting • Easier to use • Now everyone, at one time or another, has looked through a microscope

17. How Does It Work? • A microscope works very much like a telescope. • A telescope must gather light from a dim, far away object. • So, it needs a large objective lens to gather as much light as possible and a long body to bring the image into focus.

18. How Does It Work? • Unlike a telescope, a microscope must gather light from a tiny specimen that is close-by. • So the microscope does not need a large objective lens. • Instead, the objective lens of a microscope is small. • Then the image is again magnified by a second lens, called an eyepiece, as it is brought to your eye.

19. Parts of a Compound Microscope So EASY a KID could use it!

20. Base • The bottom of the microscope, used for support • Hold this part with one hand when carrying a microscope ←

21. Mirror • Reflects the light so the specimen is easier to see ←

22. Stage • The flat platform where you place your slides.  • It has a hole in it so light can shine through ←

23. Clip • Shiny clips on the top of the stage • Holds a slide in place ←

24. Arm • Supports the tube and connects it to the base • The part you hold when you carry the microscope ←

25. Coarse Adjustment • Large, round knob on the side of the microscope • Either moves the stage or the top part of the microscope up and down →

26. Fine Adjustment • Small, round knob on the side of the microscope • Used to fine tune the focus after using the coarse adjustment knob. →

27. Eyepiece → • The lens at the top that you look through. • 10X power

28. Body Tube • The long tube that holds the eyepiece and connects the objective →

29. Nosepiece • Rotating part of the microscope at the bottom of the body tube. • It holds the objective lenses ←

35. High Power Objective • The longest objective lens • The highest magnification • 40X lens (40X x10X = 400X magnification) →

36. Low Power Objective • The shortest objective lens • The lowest magnification • 4X lens (4X x10X = 40X magnification) ←

37. Mid Power Objective • The medium length objective lens • The medium magnification • 10X lens (10X x10X = 100X magnification) ←

38. Diaphragm • Controls the amount of light going through the hole in the stage →

39. Pop Quiz • What two parts should you hold when you carry a microscope? Base & Arm • Where do you put a slide? On the Stage • To focus, what knob do you turn first? Second? First, Coarse Adjustment Second, Fine Adjustment ← ← ← → ←

40. Test Your Skills . . . • Arm • Body Tube • Stage • Clip • Base • Coarse Adjustment • Fine Adjustment

41. Test Your Skills • High Power Objective • Low Power Objective • Mirror • Eyepiece • Nosepiece • Diaphragm

42. http://www.udel.edu/biology/ketcham/microscope/testFLV8.html • http://www.wisc-online.com/objects/index_tj.asp?objID=BIO905