Nature of Scientific Knowledge

The Sweeter Side of Density

In this Activity, students determine the density of different sugar solutions (0-50%). They then dye the solutions and devise a method to combine the solutions to make a multi-colored, layered heterogeneous mixture. This Activity could be used in units dealing with measurement or density.

That's the Way the Ball Bounces (or Is It?)

In this Activity, students investigate the physical properties of different balls that may look similar, but have very different rebound properties. Students also investigate how the rebound properties change when the balls are subjected to near freezing and near boiling temperatures. This Activity could be used at the beginning of the school year as an exercise in making observations.

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.

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.

Where There's Fire There's...

In this Activity, students compare the combustion of different substances such as a glowing wooden toothpick and lit birthday candle in air, oxygen, exhaled breath, and carbon dioxide environments. The oxygen and carbon dioxide are generated from supermarket chemicals. This Activity can be used to explore the chemistry of oxygen and combustion.

Out of the Blue

In this Activity, students first prepare a standard formulation for a variation on the classic blue bottle reaction using consumer chemicals. They then make appropriate changes to the formulation and observe the results to determine the roles played by each reactant. This Activity could be used with units on chemical kinetics and oxidation-reduction reactions.

Diffusion of Water through a Differentially Permeable Membrane

In this Activity, students investigate the process of osmosis through a differentially-permeable membrane formed by the precipitation of copper(II) hexacyanoferrate(II). This Activity allows students to watch and investigate osmosis, which reinforces the concept of transport in living cells.

Pondering Packing Peanut Polymers

In this Activity, students compare polystrene and cornstarch packing materials ("peanuts"). Both are made of polymers, but because of their composition, they behave very differently in various solvents. Students extrapolate how these differences in behavior relate to environmental effects, such as filling landfills with non-biodegradable materials.

Aluminum & Air Battery

In this Activity, students construct a simple battery from aluminum foil, saltwater, and activated charcoal. The battery can power a small motor or light. This Activity demonstrates oxidation and reduction reactions, which are integral parts of battery chemistry.