BIO 3A Lab: Safety and Volumetric Instruments Page 1 of 14 Updated 14-Aug-09 Biology 3A Laboratory Laboratory Safety and Measurement of Liquid Volumes: Beakers, Volumetric Flasks, Graduated Cylinders, Pipettes, and Burettes Objectives To understand the importance of laboratory safety To understand how liquid volumes are measured To investigate the accuracy of beakers, volumetric flasks, graduated cylinders, pipettes and burettes To learn basic types of pipettes and their functions To understand the use and choice of pipettes for specific measurements To demonstrate repeatable, accurate pipette techniques Introduction Department of Biological Sciences Laboratory Safety Policy Many of the reagents (chemicals) and some of the equipment in a biology laboratory are potentially dangerous. Following rules of laboratory safety and using common sense throughout the course are important to the enhancement of a student's laboratory experience. The following safety rules apply to all biology department laboratory areas.  Wear safety glasses or goggles when directed by your instructor, or during exercises in which glassware and solutions are heated, or during exercises in which dangerous fumes may be present, creating a possible hazard to eyes or contact lenses.  Wear closed-toe shoes at all times in the laboratory.  Assume that all reagents are poisonous and act accordingly. o Read the labels on reagent containers for safety precautions, and understand the nature of the chemical that you are using. o Stopper or cap all reagent bottles when not in use. o If you should get any reagent in your mouth, rinse your mouth thoroughly with water and immediately inform the laboratory instructor. If reagents come into contact with your skin or eyes, wash the area immediately with water and immediately inform the laboratory instructor. o Do not pipette anything by mouth. o Discard chemicals as instructed; if you have a question, ask your instructor. o Do not pour chemicals back into containers. o Do not taste or ingest any reagents.  Exercise great caution when using heat, especially when heating chemicals. o Do not leave a Bunsen burner or other flame source unattended.BIO 3A Lab: Safety and Volumetric Instruments Page 2 of 14 Updated 14-Aug-09 o Do not light a Bunsen burner near flammable materials. o Do not move a lit Bunsen burner. o Keep long hair and loose clothing restricted and well away from any flame. o Turn the gas valve off when the Bunsen burner is not in use. o Use proper ventilation and hoods when instructed. o Do not leave stopper in place when heating test tubes. o Handle hot glassware or lab ware with a test tube clamp or tongs.  Do not eat or drink in the laboratory, unless so directed by the instructor.  Do not smoke within 25 feet of the laboratory door.  Do no operate any laboratory equipment until you have been instructed in its use.  Do not engage in horseplay, pranks or other acts of mischief or disrespect for others.  Do not perform unauthorized experiments.  Keep your work area neat, clean, and organized.  Use extra care when working with scalpels, knives, glass tubing or other sharp-edged objects.  Wear clothing that, if damaged, would not be a serious loss, or use the provided aprons or laboratory coats, since some chemicals may damage fabrics.  Read and understand the experiments you will be doing before coming to the laboratory. o Follow the procedures set forth by the laboratory manual.  Know the location of emergency equipment o first aid kit o eyewash bottle o fire extinguisher o showers o fire blanket o telephone  Report all accidents to your laboratory instructor immediately.  Discard needles, razor blades, scalpel blades and other such items only in "Sharps" containers.  Discard cracked or broken microscope slides and other glass only in the broken glass containers.  Report all unsafe conditions to your instructor.  Clean your work area and glassware and wash your hands before leaving the laboratory.BIO 3A Lab: Safety and Volumetric Instruments Page 3 of 14 Updated 14-Aug-09 Volumetrics Typical volumetric containers used in chemistry and biology labs include beakers, flasks, cylinders, pipettes and burettes. In most cases, these are made of glass and calibrated at a specific temperature. However, for very small volume measurements, micropipettes, constructed out of plastic, with disposable tips, are used. A beaker is a simple container for liquids, very commonly used in laboratories. Beakers are generally cylindrical in shape, with a flat bottom. Beakers are available in a wide range of sizes, from 10 mL up to several liters. They may be made of glass (typically Pyrex ®) or of plastic. Beakers may be covered, perhaps by a watch glass, to prevent contamination or loss of the contents. Beakers are often graduated, or marked on the side with lines indicating the volume contained. For instance, a 250 mL beaker might be marked with lines to indicate 50, 100, 150, 200, and 250 mL volumes. The accuracy of these marks can vary from one beaker to another. A beaker is distinguished from a flask by having sides which are vertical rather than sloping. In the lab, beakers are used more often than flasks. Laboratory flasks come in a number of shapes and a wide range of sizes, but a common distinguishing aspect is a wider vessel "body" and one (or sometimes more) narrower tubular sections at the top called necks which have an opening at the top. Like beakers, laboratory flask sizes are specified by the volume they can hold. Laboratory flasks have traditionally been made of glass, but can also be made of plastic. Volumetric flasks come with a stopper or cap for capping the opening at the top of the neck. Stoppers can be made of glass, plastic, or rubber. In general, flasks can be used for making, holding, containing, collecting, or volumetrically measuring solutions. A graduated cylinder is used to accurately measure out volumes of liquid chemicals. They are more accurate and precise for this purpose than beakers or flasks. Often, the largest graduated cylinders are made of polyethylene or other rigid plastic, making them lighter and less fragile than glass. A pipette is a laboratory