Topological ideas can be used to predict a variety of textures and defects in condensed matter systems under certain conditions. This article describes one means of creating and observing textures in liquid crystals which exhibit a rich variety of such textures. The results of these observations are presented. (Author/SK)

Suggests sterile procedures which can be carried out to take a sample of blood (of one or two drops) from pupils to be used in school biology courses in the United Kingdom. (HM)

Describes a circuit which allows vectors and combinations of vectors to be illustrated by means of bright segments appearing on a c.r.o. screen. Explains how to demonstrate dendritic crystalization with cyclohexanol. Presents a circuit which, with the help of a signal generator and an oscilloscope, facilitates the understanding of the electrical…

Describes the use of benzophenone in the role of a solid state sensitizer in a photochemical isomerization and as an indicator in preparative layer chromatography for purification of the isomeride. (Author/SA)

Presents an improved technique for synthesizing acetanilide from nitrobenzene by reducing nitrobenzene with iron powder and hydrochloric acid. This experiment has been used successfully with 2,000 students during two semesters. (Author/SA)

Describes a convenient, inexpensive experiment in enzyme kinetics developed for the undergraduate biochemistry laboratory at the University of Virginia. Required are a single beam visible spectrophotometer with output to a recorder, a constant temperature, a commercially available enzyme, substrates, and buffers. (BT)

Describes a physical chemistry experiment that allows students to test the effect of ionic strength on the rates of a reaction between ions. The reduction of hexacyanoferrate III by ascorbic acid is detailed. Comparisons with the iodine clock reaction are made. (CS)

The synthesis of 1,4-diphenylbutadiene by means of the Wittig reaction is presented as suitable for organic chemistry students at the end of a basic laboratory program to apply laboratory skills and display understanding of the use of phase transfer catalysis and its application in syntheses. (CS)

An experiment is described in which undergraduate students can optimize the relative yield of sec-butylbenzene by varying molar ratio and temperature. (Author/SA)

Presents Part II of a description of a computer-oriented course on process control which has been offered at the University of Wisconsin for undergraduate students. Lecture topics and laboratory experiments are also included. (HM)

Presents a classical demonstration of polarization for high school students. The initial state of this model, which demonstrates the important concepts of the optical and quantum problems, was developed during the 1973 summer program on lecture demonstration at the U.S. Naval Academy. (HM)

Describes briefly three experiments, which are presented by three physics teachers to share their ideas with other teachers and readers. These experiments are: (1) a simple hazemeter for window pollution assessment; (2) the speed of light; and (3) the ball-bearing electric motor. (HM)

Activities for exploring the school yard with children are suggested. Emphasis is on development of the senses, studying relationships, and conducting experiments. (SA)

This experiment is designed to acquaint the student with a macromolecular synthesis of a crown ether type compound. The starting materials are readily available and the product, a cyclic polyether, belongs to a class of compounds that has aroused the interest of chemist and biologist alike. (Author/BB)

This undergraduate experiment shows that the inclusion of an appropriate additive can have a very marked effect on the physical properties of a polymer. The polymer used is polypropylene and the additives are 2-hydroxy-4-octyloxy-benzophenone and benzophenone. (BB)