Summarizes evidence for the effects of class-size reduction from experimental and nonexperimental measurements, addresses questions about the robustness of each type of estimate, and suggests hypotheses that could reconcile differences resulting from conflicting evidence. Discusses potential costs and the implications for future research into the…

Presents three examples of hands-on experiments that use an inexpensive magnetic-field sensor to quantitatively study magnetic fields. (WRM)

Presents a qualitative activity whereby students observe the effects of temperature on commercial lightsticks. Includes Internet resources. (WRM)

Discusses the complexity of chemistry concepts and the identification of instructional barriers in terms of current learning theories. Recommends teaching to improve students' conceptual understanding. Contains 34 references. (WRM)

Offers a relatively simple analysis of the asymmetrical "sticking" and rolling behavior of two balls, one steel and one rubber, on an incline. Describes an Interactive Physics (TM) simulation designed to study the problem and gives rough experimental results. (WRM)

Examines the thinking processes of 16 eighth grade science writers during laboratory report writing and explores the possibility that writing can contribute directly to science learning. Five students exhibited no mental reflection during writing whereas nine students demonstrated scientific problem solving including hypothesis and evidence…

Lists directions for creating some laboratory equipment that makes it easier for students to assess the rate at which an enzyme is modifying its target (substrate). (WRM)

Describes an experiment in which two semi-transparent reticles and a photographic plate separated by several centimeters are illuminated by a monochromatic point source in a typical in-line configuration that results in a hologram that contains information from both reticles. (Author/WRM)

Presents an activity that involves dropping spherical party balloons onto a sonic motion sensor to show that the force associated with the air resistance is proportional to both the square of the velocity and the cross-sectional area of the balloon. (Author/WRM)

Describes a chemistry experiment that allows students to calculate rates of reaction, orders of reaction, and activation energies. The activity demonstrates that to increase a reaction's rate, a catalyst need only provide any additional pathway for the reaction, not necessarily a pathway having lower activation energy. (WRM)

Presents an experiment on collecting data while measuring the dissolved-oxygen levels in Thames River tap water straight from the water mains and dissolved-oxygen levels in rainwater containing Hornwort water weed over 24 hours. (Author/ASK)

Describes a procedure based on the assumption that during the rated lifetime of a light bulb roughly half of the radius of the filament evaporates. Explains how the filament's operating temperature can be deduced. (DDR)

Presents an authentic semi-guided student research project. Studies the impact of a regional invasion of non-indigenous worm species on decomposition in forest soils. Describes the experimental design, data analysis, and interpretation of the data. (Contains 16 references.) (YDS)

Presents an experiment on mouse behavior in which students learn to observe, pay attention to details, record field notes, and ask questions about their observations. Uses a white mouse to eliminate the risk of disease that a wild rodent might carry. Lists materials, set up, and procedure. (YDS)

Describes the use of an oven bag as a sterile chamber for culture initiation and tissue transfer. Plant tissue culture is an ideal tool for introducing students to plants, cloning, and experimental design. Includes materials, methods, discussion, and conclusion sections. (SAH)