Used two experiments to assess extent to which introductory psychology students' self-selection into experiments produced biased samples. Students chose between apparently different experiments with different descriptions and between individual and group sign-up slots. Results demonstrated that students sorted themselves into experiments and into…

Introduces three demonstrations using rubber balloons: rate of reaction, air pressure, and solubility of gases in liquids. Provides the materials, procedure, questions, further investigation, and discussion in each demonstration. (YP)

This article describes the basic physics of several types of holograms and discusses different recording materials in use. Current and possible future applications of holograms are described as well as their large-scale production. (Author)

Although all students need more and better science classes to face the next century's challenges, students gifted in science also need access to dedicated teachers willing to assist their learning progress and encourage their production of original research projects. Integrating the science curriculum would also benefit gifted and other students.…

Describes an experiment demonstrating Lenz's law by measuring a magnet falling through a copper tube compared to a nonmagnet falling. Presents diagrams and pictures showing the apparatus. (YP)

Discusses the nature, resolution, focal length, and angle of a pinhole camera. Describes the development and some applications of the camera. Nineteen references are listed. (YP)

Described are the history, formation, and observing techniques of meteors and comets. Provided are several pictures, diagrams, meteor organizations and publications, and meteor shower observation tables. (YP)

Describes a model for generating solution features, or karren, on gypsum blocks within 24-48 hours in order to illustrate terrain-forming processes. This method for replicating landforms provides hands-on experience for students, and can be varied to demonstrate a number of principles. (LS)

Highlights semantic links and shows how the semantic content of hypertext links can be used for information retrieval. Discussion includes indexing and retrieval algorithms that exploit link content and node content; retrieval strategies exploiting semantic links, including conventional retrieval and constrained spreading activation techniques;…

Presents a science experiment to demonstrate the emergence of a snake from an "egg" and illustrates the necessity of heat to induce the hatching process. (MKR)

Describes experiments designed to investigate the cooling rate of microwave-boiled water as compared to that of stove-boiled water. Concludes that within experimental limits, microwave-boiled water and stove-boiled water cool at the same rate. (JRH)

Explores strategies in the situation of a runner trying to evade a tackler on a football field. Enables the student to test intuitive strategies in a familiar situation using simple graphical and numerical methods or direct experimentation. (JRH)

Shows that the conventional wisdom about the extreme inaccuracy of stopwatch measurements during the acceleration and free fall of objects is mistaken. (ZWH)