Stomata are the pores on leaves through which carbon dioxide, oxygen, and water vapor are exchanged with the atmosphere. Researchers have found that leaf stomatal densities change in response to several environmental variables, including humidity, light intensity, and atmospheric levels of carbon dioxide, a greenhouse gas (Van Der Burgh, Dilcher,…

Although the theory of evolution is the foundation of modern biology, students too rarely have an opportunity to watch selection operate in natural populations of animals. This lack may be partially responsible for the unfortunate ignorance of many people regarding the significance of evolution in biology. Laboratory exercises that directly study…

This collection of lesson plans designed for teachers of 4th- through 12th-grade students utilizes an assortment of teaching strategies for topics related to coal and the coal industry. Activities cover the following topics: coal formation; coal identification; "the geologist's dilemma" (a supply and demand activity); geologic time and…

This document describes ways to work with DNA and host organisms in precollege classrooms. The guidelines are intended to assist the teacher who already has training in working with microbes, DNA, and associated chemicals. The contents of the guidelines include: (1) Permitted DNA molecules, vectors, and recommended host organisms for constructing…

This paper attempts to promote an understanding of physics through its history and replication of the oscillation experiments of Isaac Newton and Daniel Bernoulli from the 17th and 18th centuries. The experiments described can be treated at a level of sophistication to suit the interests and capabilities of the student. Reproductions in the…

These units developed for teacher use consist primarily of a collection of typical experiments or research activities developed by staff and participants of a National Defense Education Act Institute. The institute was designed to broaden the viewpoint of 25 industrial arts teachers with regard to some of the newer scientific and/or engineering…

Presents an experiment for determining the pH of shampoo. (SL)

Describes an experiment to introduce students to qualitative and quantitative aspects of neutron activation analysis. (SL)

Suggests a laboratory introduction to solid-solid phase transitions, thermochromism, and color changes associated with changes in ligand coordination suitable for undergraduate students in physical and general chemistry. Describes the preparation and analysis of the experiment. (CW)

Describes an apparatus that can be used to measure low gas pressures over a range of temperature in the undergraduate teaching laboratory. Discusses an experimental procedure and theory for pressure temperature measurements with this apparatus. (CW)

To improve the testing of students' skills in performing laboratory experiments, 92 Israeli high school physics teachers participated in the development of a list of weighted laboratory skills. Sensory-motor coordination was found to be a significant measured factor. Factors affecting reliability were also noted. (GDC)

Cites reasons why Penicillium claviforme is an exceptionally good species for ultraviolet induced mutation experiments. Provides a set of laboratory instructions for teachers and students. Includes a discussion section. (ML)

Presents a laboratory experiment which determines critical temperature and density of carbon dioxide. Discusses critical point and provides equations to estimate liquid volume fraction. Analyzes experimental results in terms of variables. (JM)

Describes the laboratory procedures for the measurement of thermal expansion and viscosity of liquids. These experiments require inexpensive equipment and are suitable for secondary school physical science classes. (JR)

Describes a variety of experiments that can be performed using the disposable syringe. Among others, these include the removal of oxygen during rusting, convection in a liquid and in air, gas collection in an electrolysis cell, small scale production of a fog, and hydrogen/oxygen extraction from a voltameter. (JR)