1. Topic: Microscope
Aim: How can we measure a cell using a microscope?
Do Now:
1. Copy the aim onto your notes sheet.
2. Complete Microscope Check pink sheet
3. Take out a piece of loose-leaf for today’s notes.
HW: Cells and Cell Processes Exam Review Sheet (BOTH SIDES)

2. 1. Where should the microscope be safely placed?
On a tabletop or other flat surface.

3. 2. Why is the lowest power objective used first?
It provides a larger field of view.
LOW
HIGH

6. Ruler observed under low power Ruler observed under high power
SMALLER FIELD OF VIEW
LARGER FIELD OF VIEW

7. 3. Identify the objective that gives a larger field of view. Low power
HIGH

8. 4. Identify what occurs to the field of view when switching from low to high power.
The field of view decreases.
The amount of light decreases.

9. 5. Identify the part that used to focus the slide when using the 4x and 10x objectives.
Coarse adjustment

10. 6. Identify the part that used to focus the slide when using the 40x objective.
Fine adjustment

12. The diagram represents a cell in the field of view of a compound light microscope. In which direction should the slide be moved on the microscope stage to center the cell in the field of view? 1. toward A 2. toward B 3. toward C 4. toward D

13. Units to measure cells
Micrometers/Microns µm
1mm = 1000µm

14. Cells are so small that even a cluster of these cells from a mouse only measures 50 microns.

15. The human ovum is typically around between 120 to micrometers which is the largest cell in the human body. It is visible to the human eye under a microscope.

16. The head of the sperm is on average 5 to 6 micrometers
The head of the sperm is on average 5 to 6 micrometers. The flagellum is up to 50 micrometers long.

17. Paper thickness =
about 150 µm

18. Human hair diameter = µm

19. SHRIMP EGGS

20. mm  um
Move decimal three places to the RIGHT
3.2 mm = ? µm
3. 2
3200 µm

21. Are there SI units smaller than micro
Are there SI units smaller than micro???? "nano-" = 1/1,000,000,000 (billionth) "pico-" = 1/1,000,000,000,000 (millionth of a millionth, "micro micro-")

22. 0.7634mm = ? µm 
763.4 µm

23. um  mm
Move decimal three places to the LEFT
789 µm = ? mm 
.789 mm

24. 53.6 µm = ? mm 
.0536 mm

26. 1.
1mm
3.2mm =
Field of view =
3200 µm

27. 2.
500um
1mm =
1000um

28. 3.
1000um
2000/2 = 1000
2 mm =
2000um

29. 4.
500um
250um
1000um

30. 5.
1000um
500um
2000um

31. 6.
500um
250um
125um
1000um

32. 7.
2500um
1250um
625um
5mm =
5000um

33. 8.
1000um
5mm
= 5000um

34. 9.
1000um
7000um

35. 10.
400um
2000um

36. Let’s summarize:
Identify the units used to measure cells.
Which way do you move the decimal when converting from mm to um?
Which way do you move the decimal when converting from um to mm?
Describe the two procedures that must be followed before switching to high power.
Explain what happens to the amount of light in your field of view when switching from low to high power.

37. Determine the length of each cell in um.
Diameter = 1mm Diameter = 2000um
1000um
= 500um
= 500um

38. Determine the length of each cell in um.
Diameter = 1000um Diameter = 2mm
1000/6
= 2000um
= 166.7um

39. 1. Which way should you move the slide to center the cell in the field of view?
Move the slide to the right (towards B)
2. Determine the approximate length of the cell.
300um
500um
700um
1000um
700um
350um
1400um