This online calculator computes radioactive decay, timed decay, and timed solid disposal for a databank containing 116 isotopes. It also features University of British Columbia disposal limits and a unit converter and date/time calculators. These tools calculate the half-life for selected isotopes; radioactive decay final activity, given the initial activity and decay time; the decay time, given the ... Full description.

This classroom activity has students determine the concentration of oxygen in air at their location. Oxygen is removed from a trapped volume of air by the oxidation of steel wool and by measuring the volume of air remaining they can calculate the percentage of oxygen in the air. The site has a stated objective, a list of materials, procedure, activity answers, ideas from teachers, and links to related ... Full description.

This hands-on activity shows students what happens when the fresh water of a river meets the salt water of the ocean. They will make a saturated solution of colored salt water, pour it into fresh water, and observe what happens. There are also extensions to the activity in which they add a third layer of water of intermediate salinity, and test two solutions by floating a pencil in them. There is ... Full description.

This report documents the findings of a 10th-grader from Utah who decided to test water samples to find out for himself how safe the water was in his home town. The narrative essay, with illustrations and photographs, discusses how his biology class ignited his concern for environmental issues. It describes his expedition to uncover the unseen factors affecting the water quality in his town, including ... Full description.

This activity gives students an opportunity to learn about the elements created in the cores of high-mass stars by fusion reactions. They will discover that all stars start by burning hydrogen and end up creating many heavier elements inside their cores, elements that will be released into space when it dies in a supernova explosion. Students associate a layer with an element that is being produced ... Full description.

This activity describes the basic structure of an atom using an edible model and explains the quantum mechanical nature of the atom. For example, originally, each electron orbital was pictured as having a specific radius, much like a planetary orbit in the solar system. However, the modern view is not so simple. Though each orbital does have a precise energy, the electron is now envisioned as being ... Full description.

In this demonstration, an overhead projector, diffraction grating, and a series of filters are used to introduce the basic concepts of the visible electromagnetic spectrum and the relationship between wavelength and absorption of light. The overhead projector is used to project the spectrum from the diffraction grating on the board or wall. A series of colored filters are used to filter the light ... Full description.

Students will seek to understand trends that are shown by graphical analysis of ozone measurements over time. Students will investigate ozone chemistry and issues around the preservation of the Earth?s ozone layer, and learn how to read false color images of ozone concentration. They will then interpret trends from graphs of data and construct a correctly labeled graph. This lesson uses NASA images ... Full description.

This collection of experiments introduces students to techniques for measuring pH. They will learn how to use pH paper, how to use a garden soil test kit to measure the pH of liquids, how to record their observations, and some lab safety tips. In the experiments, they will measure the pH of some common substances (water, soil, and others), learn about buffering in soils and natural waters, and observe ... Full description.

This experiment will help students understand that soil sometimes contains substances, like limestone, that buffer acids or bases, and that some salts in soil may also act as buffers. They will collect soil samples from their lawn, garden, or school and look for buffering effects by observing the pH change of an acid mixture poured through the samples. If the water collected from the sample is less ... Full description.