Change, Constancy & Measurement

Flame Tests: Which Ion Causes the Color?

In this Activity, students perform simple flame tests using eleven commercially available compounds, cotton swabs, and a Bunsen burner. They then determine whether the cations or anions in each compound are responsible for the flame test colors. This Activity introduces students to flame tests in an inquiry-based manner.

Cooking Up Colors from Plants, Fabric, and Metal

In this Activity, students dye fabric squares with two plant dyes: aqueous extracts of tea leaves and of marigold flowers. They investigate how the addition of iron to a dye bath affects the resulting color and fastness of the dyed fabrics and observe that the type of fabric affects the results. This Activity can accompany a discussion of the impressive array of chemicals produced by plants.

Turning on the Light

In this Activity, students investigate the luminescent properties of common items such as glow-in-the-dark stickers, wintergreen-flavored hard candies, and a chlorophyll solution made from spinach leaves. After making observations, they use a flowchart to categorize the luminescent items as fluorescent, phosphorescent, or triboluminescent.

Garbage Juice: Waste Management and Leachate Generation

In this Activity, students use multi-colored breakfast cereal and liquid to model the concepts of leachate and leaching from municipal solid waste disposed of in a landfill. Students create a modern landfill model with the same material. This environmental chemistry Activity can be used to complement a celebration of Earth Day.

Mass Spectra

In this Activity, students solve puzzles that are analogous to finding the amino acid sequence of a peptide using mass spectrometry. Students identify words that have been broken into letters or groups of letters. In many textbooks instrumental analysis and various types of spectrometry are mentioned only in passing.

A Cool Drink!: An Introduction to Concentrations

In this Activity, students investigate concentration levels by using serial dilution to prepare several solutions of presweetened powdered drink mix. Students taste the solutions to determine at which concentration they first discern the sweetness. A connection is also made to the concentration of pollutants in air.

Cool! Rates of Heating and Cooling

In this Activity, students measure the rate of warming for a chilled thermometer bulb held in room temperature air, for a chilled bulb held between two fingers, and for a few milliliters of ice-cold water. Students discover that the warming process is not linear. This Activity emphasizes the importance of measuring temperature change and its relevance to other experiments.

Flipping Pennies and Burning Candles: Adventures in Kinetics

In this Activity, students collect data to determine whether two processes, flipping pennies and burning small birthday candles, follow zeroth- or first-order rate laws. Students first collect data on the number of pennies remaining "heads up" after several successive tosses and then measure the mass of a burning candle over time.

Nanopatterning with Lithography

In this Activity, students learn the general principles of serial and parallel nanofabrication techniques. Students use nylon spheres, contact paper, and talcum powder to form patterns. Using this macroscale analogy, students explore the parallel fabrication technique known as nanosphere lithography.

How Does Your Laundry Glow?

In this Activity, students examine the effect of pH on the intensity and color of the emission of fluorescent dyes in liquid laundry detergent. They perform two titrations using vinegar to estimate the pH at which the fluorescence properties change. In the second titration, sodium bicarbonate is added to buffer the detergent solution.