Discusses the problems of teaching time concepts to children. Suggests alternatives to the traditional time line. Describes the use of bottles and boxes as symbols of units of time when encouraging children to visualize and understand time. Provides information which will assist teachers in using these techniques. (KO)

Investigates how 11th graders think with respect to evolution and the development of species. Reports that the pupils have extensive factual knowledge, but have difficulty in relating these facts in coherent descriptions and explanations. (Author/YP)

Defines the Cognitive Difficulty Level (CDL) as number of schemes required for solution (NS) times the required learner's resources (Problem Solving Taxonomy [PST] level). Describes the validation procedures of the CDL index in high-school level electronics. (Author/YP)

Discusses the change in pressure as a balloon expands. Describes the pressure change in a spherical soap bubble and a rubber membrane on the tube. Provides demonstrations when two balloons are connected by a tube. Lists five further reading materials. (YP)

Discusses pupil misconceptions concerning forces. Summarizes some of Assessment of Performance Unit's findings on meaning of (1) force, (2) force and motion in one dimension and two dimensions, and (3) Newton's second law. (YP)

Four questions related to rain concerning aerodynamic drag force, pressure from the impact of raindrops, impact of wind on the pressure, and stopping force extended on the car by the water are proposed. (YP)

Investigates the nature of catastrophic volcanism and the rifting process. Describes two kinds of evidence: quantitative descriptions of rock melting and a wide range of observations. Discusses examples of continent growth in the North Atlantic, India and the Seychelles islands, and the South Atlantic. (YP)

Explores the possibility that the concept-mapping strategy could be a fruitful way of reducing the anxiety levels of students as well as helping to change their attitudes towards concepts. Concepts from the areas of ecology and genetics were given to pre-degree biology students. Experimental results confirmed the effect. (YP)

The difference in time between the emission and reception of light is called the "lookback" time. This article explores implications of lookback time and explains some of the puzzling questions posed by the scientific observation of cosmic history. Provides several pictures and diagrams. (YP)

Investigates the nature of college student difficulties with negative values of velocity by using interviews. Discusses graphical representation of negative values of velocity and interpretations of graphs involving negative values of force. Suggests some instructional implications from the discussion. (YP)

Discussed is the historic development of Snell's law and derivation of the law without using mathematical expressions. Describes laboratory procedures using diagrams. (YP)

Summarizes research on inquiry and investigative strategies for teaching laboratory science. Concludes that meaningful laboratory instruction is distinguished by: student engagement in science inquiry processes, student manipulation of experimental materials, and the experiential teaching of specific scientific concepts. (RT)

Investigates the effect of modeling analogy on learning of the concepts of electricity in grade 6, 8, and 10. Describes 2 analogies (train analogy and thermal analogy) with diagrams and examples. Discusses the accessibility, transferability, and difficulty of each analogy. Reports treatment effect and some further implications. (YP)

Certain misunderstandings in science, mathematics, and computer programing reflect analogous underlying difficulties. These misunderstandings are examined through four knowledge levels: (1) content; (2) problem-solving; (3) epistemic; and (4) inquiry. Analysis of several examples shows that misunderstandings have causes at multiple levels, and…

Discusses student difficulties in problem solving. Presents a structured approach to one-dimensional constant acceleration problems. Provides researcher's experience including an example problem, advantages of the approach, and student responses with two illustrations of problem solving. (YP)