FIELD OF VIEW

DO NOW: Is the field of view larger or smaller under high power? Explain.

Field of View: Measurement of the area that can be seen in the microscope. (Note: We measure the diameter of the circle) Diameter: From one end of the circle to the other through the center.

How do we know how wide the field of view is? We have to measure it while looking through the microscope. 4mm 4mm

2 mm

4 mm

how many boxes wide is the field of view? 3.5mm

What happens to the field of view when you switch to high power? Field of view gets smaller under high power. Objects appear larger, but you see less of the slide.

You have a camera with a high power lens and a low power lens. Which lens would you use if you wanted to fit all of your friends in a picture?

low power lens high power Which lens would you use if you wanted to capture the color of the last girl’s eyes?

Which lens will show the largest low power lens high power Which lens will show the largest Field Of View?

Which lens will show the most detail? low power lens high power Which lens will show the most detail?

What is the diameter of each field of view? B 5.5 3 C D 1.5 2

4mm 1mm How big is the Paramecium? When you place the grid on the stage and look at it under 40x, this is what you see. When you look at a paramecium under 40 x, this is what you see How big is the Paramecium? 1mm

The protist is about 2.5 mm. 5mm

Which has a larger FOV? 100x 400x

Sam measured the diameter of the field of view to be 2 mm Sam measured the diameter of the field of view to be 2 mm. How wide are the objects below? 2 mm 1 mm 0.5 mm 2 mm 2 mm 2 mm

DO NOW: Sue measured the diameter of the field of view to be 4 mm DO NOW: Sue measured the diameter of the field of view to be 4 mm. How wide are the objects below? 4 mm 2 mm 1 mm 4 mm 4 mm 4 mm

Measuring with a microscope

How many could fit across? 4mm 8

FOV= 4mm. 8 can fit across. 4mm 4 .5 = 8 8

Number that can fit across Size of Object Size of object = Field of View Number that can fit across

9mm

Field of view Number that can fit 3mm 3mm 3mm 9mm 3 = 3mm 9mm

Field of view Number that can fit 3mm 5 0.6 mm 3mm

DO NOW: How wide is the Amoeba? 1 mm

How wide is the euglena? 2 mm 4 0.5 mm

4mm 1mm How big is the Paramecium? When you place the grid on the stage and look at it under 40x, this is what you see. When you look at a paramecium under 40 x, this is what you see How big is the Paramecium? 1mm

Microscopic Measurement Total Low Power Magnification= 200x 4 Total High Power Magnification= 800x Low Power Field of View= 1.5 mm 4 0.4 mm High Power Field of View=

Micro Measurement 4x Magnification LP = 100x Magnification HP = 400x Field of View LP = Field of View HP = ? ? ? ? ? 4x 4mm 1mm

Low Power = 100x High Power = 400x If you can see 12 cells under low power, how many can you see under high power? 12 / 4 = 3

Low Power Diameter = 4 mm High Power Diameter = 1 mm If 1 cell could fit across the high power diameter, how big is each one? If 2 cells could fit across high power, how big is each one? 4 mm 0.5 mm

Low Power Diameter = 4 mm High Power Diameter = 1 mm If 4 cells could fit across the low power diameter, how big is each one? If 2 cells could fit across low power, how big is each one? 1 mm 2 mm

Which shows a larger Field of View? DO NOW: Which shows a larger Field of View? A B A B

Microscope Lab You will measure the field of view under different magnifications.

Microscope Lab You will find the relationship between size of field of view and magnification power.

Microscope Lab You will also estimate the actual size of the objects you view.

Pre Lab Questions: What are the three different total magnifications on our microscopes? 40 100 400

Measurement of the area that can be seen What is “Field of View”? Measurement of the area that can be seen

What do you predict will be the relationship between power of lens and size of field of view?

Power of Lens vs Size of Field of View

Width of Diameter of FOV= Scanner Lens 40 X Low Power Objective Lens 100 X High Power Objective Lens 400 X Slide A Grid Diameter of FOV (# of Boxes) _________boxes Stage Micro-meter Width of Diameter of FOV= ___________mm 4 1.5 .5 1.6 4 .4

How did you figure out the size of the objects? 4mm 1mm

Insect Scanner FOV = 4mm Insect Head to Tail= About 4 mm About 3.5 mm

Insect Eye 0.4 mm High Power FOV = 0.4mm Insect eye = 0.3 mm

One Volvox = about one third of the FOV 1.6 mm Low Power FOV = 1.6 mm One Volvox = about one third of the FOV = 0.53 mm

Paramecium 0.4 mm High Power FOV = 0.4mm Paramecium= 0.2mm

Amoeba 0.4 mm High Power FOV= 0.4 mm Amoeba = about 0.3 mm

Rules Never use coarse adjustment with high power objective!

Parts and Functions

The diagram represents a hydra as viewed with a compound light microscope. If the hydra moves to the right of the slide preparation, which diagram below best represents what will be viewed through the microscope?                                                       

The diagram to the left represents the letter "h" as seen in the low power field of view of a compound light microscope. Which diagram below best represents the field of view if the slide is not moved and the objective is switched to high power?                                                  

What is the lowest possible magnification that can be obtained using the microscope shown? 20x 200x 10x 100x

100x Center the object scan with low power

400x Then Zoom In

Why should the object be centered in the field of view before switching to high power? If you don’t, the object will not be in the field of view under high power.

To locate a specimen with a compound microscope, a student should begin with the low-power objective rather than the high-power objective because the field of view is smaller under low power than under high power field of view is larger under low power than under high power specimen does not need to be stained for observation under low power portion of the specimen that can be observed under low power is less than the portion that can be observed under high power