 A triple-beam balance determines the mass of an object in grams.  How to use a triple-beam balance: › Make sure the balance is on a level surface and that the pan can move freely › Position all the sliders to zero › Use the adjustment knob (usually located under and to the left of the pan) if the pointer does not come to rest in the middle of the scale

 How to use a triple-beam balance (con’t) › Place the mass on the pan › Move the largest rider along the beam to the right until it is at the last notch that does not move the pointer below the zero point in the center of the scale › Follow the same procedure with the next largest rider.

 How to use a triple-beam balance (con’t) › Move the smallest rider until the pointer rests at zero in the middle of the scale. › Total the readings on all the beams to determine the mass of the object.

 Compound microscopes contain a number of lenses, usually 10x in the eyepiece and 10x, 40x or 45x, and 100x (immersion oil) lenses in the objectives.  The microscope magnification is calculated by multiplying the eyepiece magnification by the objective magnification.

 Total magnificaton- › For example:  10x (eyepiece) x 100x (objective lens) = 1000x  Specimen is magnified 1000 times

 Definitions: › Resolution - the microscope’s ability to distinguish between two points that are close together. The resolving power is expressed in length › Oil immersion objective – this objective uses immersion oil to allow light to pass through it the same way light passes through the glass slide. The oil decreases the bending of the light waves allowing more light to pass directly to the specimen.

 Definitions (con’t) › Binocular – a microscope with two eyepieces as opposed to one. Most hospital laboratories use binocular microscopes.

 Components of the microscope: › Eyepiece › Arm › Base › Binocular tube › Revolving nosepiece › Objective lens › Mechanical stage

 Components of the microscope: › Stage clips › Iris diaphragm › Coarse adjustment knob › Fine adjustment knob › Lamp › Bulb › On/off switch

 Using the Microscope › Lower the stage to its lowest position using the coarse focusing knob. Always start with the 10x power objective. › Place the slide on the stage and place the stage clips on top of the slide to hold the slide in place

 Using the Microscope (con’t) › Use the coarse adjustment knob to focus on the slide, and then use the fine adjustment knob until the object is in sharp focus. › Adjust the light intensity by opening or closing the iris diaphram to give the best image

 Using the Microscope (con’t) › After focusing with the 10x objective, rotate the 40x objective into the position over the slide. Use only the fine adjustment knob to obtain a sharp image › To change slides during the investigation, follow steps 1 through 7. › At the conclusion of the laboratory investigation, lower the stage to the lowest position. Clean all lenses and place the 10x objective in position

 What is an SOP? › Documents used by laboratories to instruct personnel in how to perform particular tasks. › Provide a step-by-step outline of how a task is to be performed › Indicate in which situations the task is done, who is qualified or responsible for the work, what problems may arise and how to deal with them, and how to document that the task was performed properly.

 What is an SOP? › Since everyone in a laboratory or company follows the same SOPs when performing tasks, SOPs help ensure that work is performed correctly and consistently over time, regardless of who is doing it.

 What to think about when writing an SOP › What is the purpose of the procedure? What will be the outcome or product of the procedure? › What resources and materials will the person performing the SOP require in order to achieve the desired result?  What equipment will they need?  Does the model of equipment need to be specified?  What supplies and reagents are needed?  Is a raw material produced by a particular manufacturer needed?

 What to think about when writing an SOP › What steps will the person following the SOP perform to achieve the desired product? What must the person do to ensure that the product of the SOP is good? Are there any potential problems that the person may run into while performing the SOP? If so, how can these problems be avoided?

 What to think about when writing an SOP › Are there any potential problems that the person may run into while performing the SOP? If so, how can these problems be avoided? › It is important that the SOP be complete and clearly written so that others can follow it.