Evidence, Models & Explanation

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.

A Kool Reaction from the Fine Print

In this Activity, students gain an understanding of the importance of reading reagent labels both in chemistry class and on consumer products. Students explore the chemistry behind the directive on a package of Kool-Aid "Do not store in a metal container". The Activity illustrates properties of acids and metals.

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.

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.

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.

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.

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.

The Nature of Hydrogen Bonding

In this Activity, students build models of polarized water molecules using K’nex toy components and adhesive Velcro. Students investigate hydrogen bonding by shaking the models in various ways. They observe the resulting interactions and relate their observations to physical states of water and the difference between strong bonds and weak attractions.