Tools of the Biologist- Name That Tool!

A Review of Using SI Units in Biology Biology labs often include the collection of data. Data not only includes making observations but recording measurements such as length, mass, volume and temperature. SI measurements are based upon a basic unit. metergram liter O Celsius All SI units are based upon the multiples of 10.

Micro  Milli  Centi  Basic Unit  Kilo / 1000/10 /100 /1000 When going from a smaller unit to a larger unit DIVIDE or Move the decimal point to the left Micro  Milli  Centi  Basic Unit  Kilo X 1000 X 10 X 100 X 1000 When going from a larger unit to a smaller unit MULTIPLY or Move the decimal point to the right

The Compound Light Microscope Magnifies specimen. Allows light to pass through the specimen. A reverse image. 1.Body Tube 2.Nosepiece 3.4X Objective 4.10X Objective 5.40X Objective 6.Stage Clips 7.Diaphragm 8.Lamp 9.Ocular 10.Arm 11.Stage 12.Coarse Adjustment 13.Fine Adjustment 14.Base

Ocular or Eyepiece: Part of the microscope you look through. Magnifies image 10X. Nosepiece: Rotates to change objective. Objective: 4X low power- magnifies 4X. 10X medium power – magnifies 10X. 40X high power- magnifies 40X. Stage: Where specimen is placed for viewing. Stage Clips: Holds slides in place. Diaphragm: Controls the amount of lights entering the microscope. Iris Diaphragm Disc Diaphragm

Coarse Adjustment Knob: Used for focusing under low power. Fine Adjustment Knob: Used for focusing under high power. Total Magnification: Ocular X Objective Ocular = 10X Low power Objective = 4X 10 X4 = 40X Total Magnification Field of View: Circular area of light you observe when looking into microscope. As magnification increases from low Power 4X to high power 40X, the size of the field the field of view decreases, And you will see more detail.

Reverse Image: When observing specimens in the microscope the Imaged you observe is a reversed image of how it sits on the slide. e e Resolution: The resolving power of a microscope is the ability to Clearly determine two separate points, or objects, as singular, Distinguishing entities.

Depth of Field: R efers to the thickness of the plane of focus. With a large depth of field (low power), all of the threads can be in focused at the same time. With a smaller or narrower depth of field (high power), only one thread or a part of one thread can be focused, everything else will be out of focus. In order to view the other threads, you must focus using the fine adjustment, downward to view the ones underneath and upward to view the ones that are above.

Calculating High Power Field Diameter Low Power Magnification = X (High Power Field Diameter) High Power Magnification Low Power Field Diameter Measuring Field Diameter ______________mm ________________um 4 x = Cross multiply 40X = 16 Divide each Side by 40 40X = X = 0.40 mm 0.40 mm = ____________ um

Calculate the width of one cell observed under high power With a field diameter of 0.30mm 0.30 / 2 = __________mm 0.30/ _________ = _________mm