Lab Skills and Safety Demonstrations

See also: Measurement and Units

Lab skills and safety demonstrations teach essential techniques and practices for working responsibly in a laboratory. They are foundational because mastering safety and basic skills ensures that all other experiments can be carried out successfully.

Demonstration	Materials	Difficulty	Safety	Summary
Using a Burette	★★☆	★☆☆	★☆☆	A buret is a precise laboratory instrument used to deliver measured volumes of liquid. By reading the initial and final liquid levels, the exact volume dispensed can be calculated to a high degree of accuracy.
Wet Mount Microscope Slide	★★☆	★☆☆	★☆☆	A wet mount slide allows you to observe living cells or microorganisms in a drop of liquid under a microscope. It is a simple and quick method, but requires careful handling to avoid air bubbles and excess liquid.
Thermal Decomposition of Ammonium Chloride	★★☆	★☆☆	★★☆	Ammonium chloride, when heated, undergoes decomposition into hydrogen chloride and ammonia gasses, before reforming when cool. The process appears similar to sublimation and deposition.
Limewater Test for Carbon Dioxide	★★☆	★☆☆	★☆☆	Carbon dioxide can be detected by bubbling the gas through limewater, which is a solution of calcium hydroxide. If carbon dioxide is present, the limewater turns milky or cloudy white due to the formation of calcium carbonate.
Use of Volumetric Pipette	★★☆	★★☆	★☆☆	Correct technique for using a glass volumetric pipette.
Gravity Filtration	★★☆	★☆☆	★☆☆	Gravity filtration is a laboratory method used to separate a solid residue from a liquid filtrate by passing the mixture through filter paper held in a funnel. The technique allows suspended solids to be collected while the clear liquid passes through.
Teaching Hand Washing with UV Light	★★★	★☆☆	★☆☆	Students apply a special hand wash training lotion that glows under UV light, then wash their hands. Areas that were not washed thoroughly will still glow, providing a visual demonstration of the importance of using soap and washing all parts of the hands.
Dart Drop Accuracy, Precision, and Uncertainty	★★☆	★☆☆	★★☆	Students drop different darts onto a target from varying heights and by different droppers, then analyze how accuracy (closeness to the center), precision (clustering), and uncertainty (spread/standard deviation) change with those variables.
Investigating Plant Growth	★☆☆	★☆☆	★☆☆	Students set up several seedling pots to test one need at a time by comparing a control with three treatments: no water, salt water, and no light. They track growth over time using simple height markings to decide which conditions help plants stay healthy.
Use of Laboratory Balances	★★☆	★★☆	★☆☆	This demonstration explains the correct use of analytical and top-loading balances in the laboratory. It covers accuracy requirements, weighing techniques, and best practices to ensure precise and reliable mass measurements.
Bunsen Burner Operation	★★☆	★☆☆	★☆☆	This demonstration outlines the safe and correct use of a Bunsen burner, including preparation, lighting, use, and shutdown.
Using a Measuring Cylinder	★★☆	★☆☆	★☆☆	This demonstration shows how to correctly measure the volume of a liquid using a measuring cylinder, a common piece of laboratory equipment.
Wafting Demonstration with Ammonia	★★☆	★☆☆	★☆☆	This demonstration shows why it is important to waft chemical vapors instead of smelling them directly. Ammonia vapor rising from an ammonium hydroxide solution is detected by phenolphthalein-treated paper, which turns pink in the presence of the base.
Using Volumetric Flasks	★★☆	★★☆	★☆☆	Volumetric flasks are precision glassware designed for preparing exact solution volumes, most often used for making dilutions and standard solutions. They allow accurate adjustment of a liquid to a single graduation mark, ensuring reliable concentrations for laboratory testing.

Materials
★☆☆ Easy to get from supermarket or hardware store
★★☆ Available in most school laboratories or specialist stores
★★★ Requires materials not commonly found in school laboratories

Difficulty
★☆☆ Can be easily done by most teenagers
★★☆ Available in most school laboratories or specialist stores
★★★ Requires a more experienced teacher

Safety
★☆☆ Minimal safety procedures required
★★☆ Some safety precautions required to perform safely
★★★ Only to be attempted with adequate safety procedures and trained staff