A simple and reliable didactic laboratory has been developed to illustrate fundamental concepts of hydrophilicity, hydrophobicity, wetting, and spreading phenomena for undergraduate students. The described laboratory includes preparation of surfactant solutions at different concentrations and applying droplets of these solutions on a hydrophobic…

Unlike the large number of laboratory experiments on phase-transfer catalysis (PTC) that focus on a catalyzed chemical process, the present laboratory emphasizes the mechanism of phase transfer catalysis itself. Students can follow visually the actual transfer of the reagent by the catalyst, and its consumption in the organic phase, in a…

Although lab activities play an important role in physics teaching, many of these activities do not attain the expected objectives. Many reasons can be advanced for this, such as a lack of apparatus/equipment in schools, limits to the lab time allocated, teachers' lack of knowledge and skills about lab-oriented teaching methods or the teachers'…

We report a case study of model-based reasoning in which a small group of fourth-grade students analyzes the energy flow when a solar panel is used to power an electric motor that spins a propeller. In developing their explanation of energy flow, the students draw on a general model of energy developed collectively by their class in the course of…

Medical laboratory technology major was set up to meet rapid development of science and medical research technology in 2013. Students majoring in medical laboratory had learnt a lot of techniques distributed among different specialized courses. But, they did not understand why they had to learn these techniques and how they were applied in a…

The development and evaluation of a two-session laboratory class, based on Geneswitch technology and sex determination in the fruit fly Drosophila melanogaster, is described. Geneswitch system allows conditional control of gene expression. A laboratory exercise has been devised for sophomores in order to illustrate how Geneswitch technology can be…

This paper presents a method to measure the movement of an object from specific locations on a straight line using an iPhone's magnetometer. In this method, called "magnetogate," an iPhone is placed on a moving object (in this case a toy car) and small neodymium magnets are arranged at equal intervals on one side of a straight line. The…

This article describes an experiment teaching polarization phenomena and the Triboelectric Series in a unit on electrostatics. Using rods (2-3 ft in length) made from wood, aluminum, PVC, and Plexiglas on an inverted watch glass, these items demonstrated to the class how a party balloon rubbed with fake rabbit fur (charging the balloon negative)…

Experiments that measure the speed of sound in air are common in high schools and colleges. In the Kundt's tube experiment, a horizontal air column is adjusted until a resonance mode is achieved for a specific frequency of sound. When this happens, the cork dust in the tube is disturbed at the displacement antinode regions. The location of the…

This paper describes a simple experiment that lets first-year physics and engineering students discover an important physical property of a Slinky. The restoring force for the fundamental oscillation frequency is provided only by those coils between the support and the Slinky center of mass.

Melton demonstrated a surprising disappearance using total internal reflection. When he put a Florence flask filled with marbles into a water tank and looked straight down from directly above the flask, he was only able to see marbles above a certain water level. When he added more water into the tank above the top line of the marbles, all of the…

Students often tend to compartmentalize material learned in school. While we see this phenomenon within our own classes, it is even more apparent that students have difficulty making connections between their math and physics courses. We believe that hands-on experiments are particularly useful in helping students make these connections. In this…

This research reports the assessment of pre-service teachers' reception and attitudes towards virtual laboratory experiments in Life Sciences with the aim of advancing adaptability to digital learning. Using sequential mixed-methods in a quasi-experimental design, 68 pre-service teachers in the 3rd year of a Bachelor of Education (B.Ed) program…

To be able to design a laboratory course it is important to know what laboratory skills students possess before the course starts. This way the course can focus on developing skills in areas that are lacking. Despite the extensive literature on laboratory education, there are few studies on what laboratory skills students have at this stage of…

Three days into the academic year, the COVID-19 pandemic abruptly led to emergency remote teaching, ERT, of Chemical Experimentation--a revised alternative to the majors' General Chemistry Laboratory at the University of Costa Rica. The course was reoriented to support students' development of nontechnical experimentation skills and scientific…