Nature of Scientific Knowledge

Testing for Iodide in Table Salt

In this Activity, students use supermarket chemicals to test samples of table salt for the presence of iodine, an essential micronutrient added as iodide ion. The presence of iodide in the salt is made apparent by the appearance of a blue color.

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.

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.

Hold the Heat: Global Warming and Calorimetry

In this Activity, students perform quantitative calorimetric measurements on samples of ice/water heated by incandescent light bulbs and/or convection with room-temperature surroundings. They measure and graph temperature as a function of time.

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.

Fun with Fingerprints: Cyanoacrylate Fuming

In this Activity, students develop fingerprints using the cyanoacrylate fuming method on different types of surfaces. They investigate the technique’s effectiveness and test the effects of changing the temperature and humidity of the fuming chamber.

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.

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.

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.

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.