categories:measurement



Measurement and Units Demonstrations

See also: Chemical Quantities and Calculations, Lab Skills and Safety

Measurement and units demonstrations show how scientists quantify observations using standard systems. They are essential because consistent measurement underpins all of science, and clear demonstrations help students see why accuracy and units matter.

DemonstrationMaterialsDifficultySafetySummary
Angle of Repose★★☆★☆☆★☆☆This experiment determines the flow characteristics of powders by measuring the angle of repose—the steepest angle at which a material can rest without sliding. Sand samples of different particle sizes and moisture contents are poured to form heaps, and the angle of each heap is measured to evaluate how size, shape, and cohesion affect powder flowability.
Burning Steel Wool Increases Its Mass★★☆★★☆★★☆When steel wool is ignited, it reacts with oxygen in the air to form iron oxide. Surprisingly, the mass of the steel wool increases after burning because oxygen atoms from the air combine with the iron atoms.
Conservation of Mass with Baking Soda and Vinegar★★☆★☆☆★☆☆This experiment shows that matter is not created or destroyed in a chemical reaction. When baking soda reacts with vinegar, carbon dioxide gas inflates a balloon, and the total mass before and after the reaction remains nearly the same.
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.
Extrapolation and Interpolation With Spaghetti★★☆★☆☆★☆☆Students measure the mass and length of broken pieces of dry spaghetti, plot the data on a graph, and use a line of best fit to predict the mass of unmeasured lengths. This activity introduces the use of graphs for making predictions and demonstrates proportional relationships between variables.
Limiting Reactant★☆☆★★☆★☆☆Balloons filled with different amounts of baking soda are attached to flasks containing vinegar, producing varying amounts of carbon dioxide gas.
Lung Capacity Test★☆☆★☆☆★☆☆Use an inverted, water-filled bottle and a tube to capture the volume of exhaled air by water displacement. Counting marked volume intervals on the bottle estimates vital lung capacity.
Measure the Earth★★☆★★☆★☆☆Using a stick, a measuring tape, and basic geometry, students can replicate Eratosthenes’ ancient experiment to measure the size of the Earth. By measuring the length of a stick’s shadow during the equinox, they calculate Earth’s circumference with surprising accuracy.
Measuring Parallax Distance★★☆★★☆★☆☆Use a simple, home-built angle measurer and a known baseline to measure the parallax angle of a nearby target against a distant reference, then calculate the target’s distance with basic trigonometry. The activity demonstrates how stellar parallax works using everyday objects and spaces.
Measuring the Speed of Sound with a Drum★★☆★☆☆★☆☆One student beats a drum at a steady rate while others back away until the strike is seen at the same instant the previous beat is heard. Using the beat period and the measured distance at that point, students estimate the speed of sound.
Performing a Titration★★☆★☆☆★☆☆A standard solution in a buret is added to an unknown solution in a flask until the reaction reaches its endpoint, signaled by an indicator color change (or pH jump). Initial and final buret readings are used to calculate the unknown molarity.
Scale Model of the Solar System★☆☆★☆☆★☆☆Students calculate and build a scale model of the solar system using beads, string, chalk, or yard markers to represent planet distances, sizes, or both. The activity demonstrates the vast differences in planetary distances and diameters, helping students grasp the scale of our solar system.
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.
Use of Volumetric Pipette★★☆★★☆★☆☆Correct technique for using a glass volumetric pipette.
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.
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.

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