Measurement of the level of a liquid is needed in many hydrodynamic situations. In the present article, this has been achieved with a conductivity sensor for the specific case of water levels. The use of this system is illustrated by the automation of a gasometer in which the gas is collected in an inverted measuring cylinder resting in a water…

A device that can demonstrate equilibrium, kinetic, and thermodynamic concepts is described. The device consists of a leaf blower attached to a plastic container divided into two chambers by a barrier of variable size and form. Styrofoam balls can be exchanged across the barrier when the leaf blower is turned on and various air pressures are…

Using the traditional serological tests and the most novel techniques for DNA fingerprinting, forensic scientists scan different traits that vary from person to person and use the data to include or exclude suspects based on matching with the evidence obtained in a criminal case. Although the forensic application of these methods is well known,…

In this article, we describe an inexpensive, two-session undergraduate laboratory activity that introduces important molecular biology methods in the context of biodiversity. In the first session, students bring tentatively identified flies (order Diptera, true flies) to the laboratory, extract DNA, and amplify a region of the mitochondrial gene…

The science and technology of radio receives little attention in contemporary education. This article discusses ways to explore the basic operating principles of radio. (Contains 4 figures, 3 footnotes, and 2 notes.)

This is the story of how a typical middle school lab was transformed into an open-ended inquiry experience through a few small, but very powerful, changes. By allowing students to follow their own questions, the classroom filled with enthusiasm and students learned much more about photosynthesis, respiration, and the scientific processes. The…

A simple in class laboratory illustrating the principles of ion exchange chromatography as a bioseparation technique is described. A protein's isoelectric point as a driving force for ion exchange chromatography is easily demonstrated by using combinations of proteins with natural color or fluorescence, such as DsRed2, enhanced green fluorescent…

Children learn about properties of materials as they walk through a fabric store, help in the kitchen, or dig in the garden. Directed explorations in the classroom build on these early experiences. In the inquiry-based activity described here, students prepare to learn about wet and dry ingredients (liquids and solids) and how they mix together by…

For several years, the author's fifth-grade students raised and observed plants, kept journals, and analyzed the functions of the parts of a plant. But this year, a near disaster taught her a lesson and increased the value of the activity for her students. Not only did students learn about plants, they now understand what a variable is and how…

This paper describes some computer-based activities to bring the study of charged particle optics to undergraduate students, to be performed as a part of a one-semester accelerator-based experimental course. The computational simulations were carried out using the commercially available SIMION program. The performance parameters, such as the focal…

Light from a rough sample surface illuminated with a laser consists of a speckle pattern. If the surface evolves with time, the pattern becomes dynamic, following the activity of the sample. This phenomenon is used both in research and in industry to monitor processes and systems that change with time. The measuring equipment generally includes…

We show the impossibility of harvesting power from rotational motions by devices attached to the rotating object. The presentation is suitable for students who have studied Lagrangian mechanics. (Contains 2 figures.)

The predator-prey relationship is one of the most recognizable and well-studied animal relationships. One of the more striking aspects of this relationship is the differential natural selection pressure placed on predators and their prey. This differential pressure results from differing costs of failure, the so-called life-dinner principle. If a…

We describe a study of programs to deepen families' scientific inquiry practices in a science museum setting. The programs incorporated research-based learning principles from formal and informal educational environments. In a randomized experimental design, two versions of the programs, called "inquiry games," were compared to two control…

One of those who failed to establish himself as a natural philosopher in 18th century Paris was the future revolutionary Jean Paul Marat. He did not only publish several monographs on heat, optics and electricity in which he attempted to characterise his work as being purely empirical but he also tried to establish himself as a public lecturer.…