Describes an inexpensive and convenient way to solve the problem of maintaining the proper humidity needed in incubation chambers. (JN)

Errors in determining the effectiveness of mouthwashes, disinfectants, and other household products as antibacterial agents may result from using broth cultures and/or irregularly shaped bits of filter paper. Presents procedures for a better technique and, for advanced students, two additional procedures for introducing quantitative analysis into…

Describes new methods of collecting and examining ciliates, particularly those found in the sediments of lakes, rivers, and estuaries. Discusses extraction methods in preparation for observations in the classroom. Suggests investigations of ciliate ecology as an area of increasing research interest. (JM)

Explains a projectile motion experiment involving a bow and arrow. Procedures to measure "muzzle" velocity, bow elastic potential energy, range, flight time, wind resistance, and masses are considered. (DH)

Described is an activity which uses a 96-well reaction plate and soda straws to construct a model of the periodic table of the elements. The model illustrates the ionization energies of the various elements. Construction of the model and related concepts are discussed. (CW)

To integrate a research/discovery component into one course, an experiment using the sea urchin embryo system is introduced because the teacher manages only one organism and students provide the variables. The materials, handling methods, and experimental methods of the experiment are described. (YP)

Described is an activity in which students learn how a battery produces electricity, why at least one electrode is destroyed when electricity is produced, and how electrolytes and temperature affect the process. Needed materials and directions for building a battery are listed. (KR)

Describes a series of activities for demonstrating the conditions necessary for burning (fuel, oxygen and temperature) plus several related phenomena. (CP)

Identifies the characteristics and components of a quality laboratory program for secondary science students. Suggests approaches, questions, and activities that aim to provide challenging experiences in the sciences. Also provides a listing of recommended laboratory standards and procedures. (ML)

Discusses the rationale for using photochemistry to merge descriptive chemistry and molecular orbital theory in first-year chemistry courses. Includes procedures and safety information for various activities, demonstrations, and experiments involving photochemical reactions. (DH)

Described is an activity where students prepare high-quality fossil specimens to demonstrate the theory of evolution. The technique needed for fossil removal, the geologic and paleoclimatic setting, and the fish morphology are discussed. (KR)

Described is an astronomy lesson designed to explore the relationship between the angle of the sun, the position of the north star, and the horizon line of a local area. Activities for teaching protractor fundamentals are included. (CW)

Small-scale chemistry employs a modern design philosophy and small, inexpensive plastic apparatus to create a learning laboratory that fosters creativity, invention, and problem solving. This article describes the characteristics of the small-scale activities. A n-solutions chemical reaction matrix is provided with examples of classroom use. (YP)

An activity that can be used to teach plant nutrition and the use of hydroponics is presented. Materials and procedures are discussed. Possible topics for science projects are suggested. (CW)

Presented is an activity in which the composition of margarine is analyzed. Materials and procedures are discussed. An extension activity on emulsions is suggested. Background information on the history of margarine is provided. (CW)