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Unit 1Lesson 4 2 min read

Laboratory Techniques and Safety

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Learning Objectives

Identify common pieces of laboratory glassware and their uses.
Describe the proper use of a Bunsen burner and a compound light microscope.
Outline basic laboratory safety rules.

Tools of the Trade and Rules of the Road

Proper technique and a strong understanding of safety are paramount in any scientific laboratory.

Common Laboratory Glassware

Beaker: A simple cylindrical container with a flat bottom, used for stirring, mixing, and heating liquids. Markings are approximate.
Erlenmeyer Flask: A cone-shaped flask with a narrow neck. The neck helps prevent splashes and reduces evaporative losses. Used for titrations and holding reacting liquids.
Graduated Cylinder: A tall, cylindrical piece of glassware with precise volume markings. Used for accurately measuring the volume of liquids.
Volumetric Flask: A flask with a long neck and a single calibration mark. It is designed to hold one specific, highly accurate volume of liquid (e.g., 250 mL). Used for preparing solutions of known concentration.
Test Tube: A small glass tube used to hold and mix small amounts of chemicals.

Key Laboratory Instruments

Bunsen Burner: A gas burner used for heating, sterilization, and combustion.
Proper use: Produces a hot, blue, roaring flame when the air hole is open, and a cooler, yellow, luminous safety flame when it is closed. Always turn on the gas before bringing a striker to the top of the barrel.
Compound Light Microscope: An instrument used to view objects that are too small to be seen by the naked eye.
Proper use: Always start with the lowest power objective lens. Use the coarse adjustment knob to find the initial focus, then use the fine adjustment knob to sharpen the image. Never use the coarse adjustment knob with high-power objective lenses, as this can crash the lens into the slide.

Basic Laboratory Safety

Always wear appropriate Personal Protective Equipment (PPE), including safety goggles, a lab coat, and closed-toe shoes.
Never eat, drink, or chew gum in the laboratory.
Know the location of safety equipment, such as the fire extinguisher, eyewash station, and safety shower.
Never perform unauthorized experiments. Follow all instructions carefully.
When diluting acid, always add acid to water, never the other way around, to avoid a dangerous exothermic reaction that can cause splashing. (Mnemonic: 'Do as you oughta, add acid to water').
Dispose of all chemical waste properly according to instructions.

Key Terms

Beaker
A lipped cylindrical glass container for laboratory use, with approximate volume markings.
Graduated Cylinder
A common piece of laboratory equipment used to measure the volume of a liquid, with a high degree of accuracy.
Bunsen Burner
A type of gas burner used in laboratories, which produces a single open gas flame, and which is used for heating, sterilization, and combustion.
Compound Light Microscope
An optical instrument for forming magnified images of small objects, consisting of an objective lens and an eyepiece.
Personal Protective Equipment (PPE)
Protective clothing, helmets, goggles, or other garments or equipment designed to protect the wearer's body from injury or infection.

Check Your Understanding

1

Which piece of glassware should be used to measure out exactly 150 mL of a liquid: a 250 mL beaker or a 250 mL graduated cylinder?

2

When focusing a specimen under a compound light microscope, why should you never use the coarse adjustment knob with the high-power objective lens?

3

When diluting a concentrated acid with water, what is the correct procedure?