A relatively simple opto-electronic setup is described that utilizes a cadmium sulphide (CdS) photoconductive cell to detect resonance of a stretched vibrating string or wire. The display may be either an oscilloscope or a frequency counter. Also describes an inexpensive socket for flanged-base light bulbs. (JN)

Describes two demonstrations that require almost no preparation time, are visually stimulating, and present a variety of material for class discussion (with sample questions provided). The first involves a sodium bicarbonate hydrochloric acid volcano; the second involves a dissolving polystyrene cup. Procedures used and information on…

Describes an experiment (carried out in less than two hours) in which the merits of countercurrent extraction are immediately evident by visible colors. The experiment requires eight 125-ml separatory funnels, 250ml of 1-butanol, 250ml of 0.1-0.5 molar hydrochloric acid, and a small amount of Sheaffer's Skrip blue-black soluble ink. (JN)

Discusses materials needed, procedures used, and typical results obtained for experiments designed to make a numerical stepwise study of the oxygenation of hemoglobin, myoglobin, and other oxygen carriers. (JN)

Provides basic information on the anatomy, physiology, behaviors, and distribution patterns of the box turtle. Offers suggestions for the turtle's care and maintenance in a classroom environment. (ML)

Background information, procedures used, and typical results obtained are provided for an experiment in which students prepare and study the characteristics of a "slime." A list of general, inorganic, and polymer chemistry concepts fostered in the experiment is included. (JN)

Discusses materials needed, procedures used, and typical results obtained for an experiment involving a dry attack of ores with pyrosulfate flux. The experiment has been carried out by about 150 students a year with a demonstrator-to-student ratio of about 1:15 with no serious accidents. (JN)

Books that may help children appreciate and understand feats that can be performed because of scientific and technological discoveries are discussed. (DF)

To demonstrate negative feedback a power amplifier is constructed from an operational amplifier together with a complementary pair of transistors as an output stage. The amplifier is developed and tested stage by stage, and at each stage the defects apparent at the previous stage are eliminated. (JN)

Presents evidence which, on one hand, disconfirms storage interpretations of the constituent boundary effect and, on the other hand, supports a specific retrieval interpretation. (Author)

Presents a more precise analysis of the way in which semantic constraints affect the perception of reversible sentences. (Author/RK)

This paper presents results from a preliminary investigation in which researchers manipulated the cover story of an open-ended assessment that required students to design an experiment. Participants were 27 sixth graders from a culturally diverse urban school. In one version of the cover story, students were asked to design an experiment to test a…

A Classroom teaching method for elementary schools utilizes the physical stimuli of spatial outlays (stations) in conjunction with organized discovery.'' Stations for math, art, and social science are described. (JB)

The present study contrasted the robustness of the WSD and the F test to heterogeneity of variances. (Author)