Instructional Laboratory Experiment Research Articles

Evaluating the level of inquiry in postsecondary instructional laboratory experiments: results of a national survey

A national survey on chemistry instructional laboratories was administered to faculty members at four-year postsecondary institutions in the United States for the purpose of exploring levels of inquiry-based instruction implemented in laboratory courses. Respondents were asked to rate the level of choice their students had in deciding six key characteristics of the experiments used in their course (e.g., what research questions to explore); the more choices students get to make, the more inquiry-based instructional experience. MANOVA and post hoc analyses suggest that there are differences in the level of inquiry across chemistry course levels; lower-level courses (i.e., general chemistry and organic chemistry) implement lower levels of inquiry-based laboratory instruction compared to upper-level courses (i.e. more chemistry major-focused courses). We found no evidence of association between the level of inquiry courses and institutions’ highest chemistry degree awarded, American Chemical Society approval to award certified bachelors degrees, or external funding to transform postsecondary chemistry courses. Our study contributes to the chemical education community's growing understanding of the state of postsecondary chemistry laboratory instruction. Results further suggest that there is an opportunity for faculty members and department leaders to reflect on their instructional laboratory courses and implement more inquiry-based instructional laboratory experiences across the entirety of the postsecondary chemistry curriculum.

Phase plot of a gravity pendulum acquired via the MEMS gyroscope and magnetic field sensors of a smartphone

A gravity pendulum experiment in which a smartphone serves as pendulum bob and as measurement device is described. As the pendulum oscillates, the smartphone gyroscope and magnetometer sensors are used to simultaneously record the bob's angular velocity and angular displacement. While the angular velocity is measured directly via the gyroscope sensor, the angular displacement is deduced from the change of the magnetometer reading while the smartphone oscillates in the constant magnetic field of the Earth. These two independent measurements enable us to derive the phase space representation of the pendulum motion directly from experimental data. Further data analysis yields energy plots, including the periodic change between the pendulum's kinetic and potential energy and the energy dissipation due to friction. Detailed instructions on how to adopt the experiment, which is both suitable as a lecture demonstration as well as an instructional laboratory experiment, are provided in the supplementary material.

Photoelectric effect measurements on a conventional neon bulb

This work outlines a new instructional laboratory experiment focused on the photoelectric effect and the determination of Planck's constant. The described laboratory system employs contemporary experimental techniques, including real-time data acquisition based on the use of Arduino boards. The basis of this experiment is to measure the associated turn-on voltages of a small neon bulb as it is illuminated with several different optical wavelengths. Six different LED and laser illumination sources were used with wavelengths ranging from UV (383 nm) to red (659 nm). A plot of the bulb's turn-on voltage as a function of the inverse of the excitation wavelength showed a linear relationship with a high correlation coefficient. Planck's constant was determined from this plot, yielding a value of h=7.4±1.1×10−34 J·s. Additionally, the system allows for experimental verification of the independence between excitation light intensity and the energy needed to ionize the gas inside the bulb.

Visualizing sound waves with schlieren optics

Using schlieren optics as a tool to see the invisible, we describe a technique of visualizing traveling ultrasonic (28 kHz) sound waves in real time. Suitable for lecture demonstration purposes or as an instructional laboratory experiment, our setup can readily demonstrate the reflection of sound waves from surfaces, diffraction effects around objects, interference, and standing waves. Additionally, the incorporation of color filters provides information such as gradient directions and sound wave phase differences not obtainable with just a white light source. As an example, acoustic standing waves are analyzed.

A portable shield for a neutron howitzer used for instructional and research purposes

Neutron howitzers are routinely used in universities to activate samples for instructional laboratory experiments on radioactivity. They are also a convenient source of neutrons and gammas for research purposes, but they must be used with caution. This paper describes the modeling, design, construction, and testing of a portable, economical shield for a 1.0 Curie neutron howitzer. The Monte Carlo N Particle Transport Code (MCNP5) has been used to model the 239PuBe source and the howitzer and to design the external neutron and gamma shield.

Simulating interference and diffraction in instructional laboratories

Studieshave shown that standard lectures and instructional laboratory experiments are not effective at teaching interference and diffraction. In response, the author created an interactive computer program that simulates interference and diffraction effects using the finite difference time domain method. The software allows students to easily control, visualize and quantitatively measure the effects. Students collected data from simulations as part of their laboratory exercise, and they performed well on a subsequent quiz, showing promise for this approach.

Determining the muon mass in an instructional laboratory

An instructional laboratory experiment to measure the muon mass is described. Using coincidence-anticoincidence detection, the decay of a cosmic-ray muon into an electron (or positron) is observed in a multiplate spark chamber, and recorded with a triggered CCD detector. The energy of the charged decay-product particle is quantified by counting the number of spark gaps ns it traverses before being stopped by the chamber’s aluminum plates. By running this apparatus under computer control for several hours, the number of product particles N(ns) with various ns-values is obtained. The muon mass is obtained by a least-squares fit of the experimentally observed N(ns) to simulation values predicted for this distribution by the Fermi description of muon decay via the weak interaction. We present our results for the muon mass and discuss the simulation we developed to account for the observed skewing of N(ns) due to the various directions the spark-producing product particles move as well as the escape of some of the higher-energy particles from the chamber.

The Virtual ChemLab Project: A Realistic and Sophisticated Simulation of Organic Synthesis and Organic Qualitative Analysis

In the past four years we have created a set of sophisticated and realistic laboratory simulations for use in freshman- and sophomore-level chemistry classes and laboratories called Virtual ChemLab. We have completed simulations for Inorganic Qualitative Analysis, Organic Synthesis and Organic Qualitative Analysis, Fundamental Experiments in Quantum Chemistry, Gas Properties, Titration Experiments, and Calorimetry. The purpose of our simulations is to reinforce concepts taught in the classroom, provide an environment for creative learning, and emphasize the thinking behind instructional laboratory experiments. We have used the inorganic and organic simulations extensively with thousands of students in our department at Brigham Young University. Some important learnings from our evaluation include: (i) students enjoy using these simulations and find them to be an asset in learning effective problem-solving strategies, (ii) students like the fact that they can both reproduce experimental procedures and explore various topics in ways they choose, (iii) students naturally divide themselves into two groups: creative learners, who excel in an open-ended learning environment, and structured learners, who struggle in this same environment, and (iv) students almost uniformly agree that these simulations help them learn chemistry. In this article, we will describe the Organic Synthesis and Organic Qualitative Analysis simulation; we will also share specific evaluation findings from using the organic simulation in a laboratory setting.

The Virtual ChemLab Project: A Realistic and Sophisticated Simulation of Inorganic Qualitative Analysis

We have created a set of sophisticated and realistic laboratory simulations for use in freshman- and sophomore-level chemistry classes and laboratories called Virtual ChemLab. We have completed simulations for Inorganic Qualitative Analysis, Organic Synthesis and Organic Qualitative Analysis, Experiments in Quantum Chemistry, Gas Properties, Titration Experiments, and Calorimetric and Thermochemical Experiments. The purpose of our simulations is to reinforce concepts taught in the classroom, provide an environment for creative learning, and emphasize the thinking behind instructional laboratory experiments. We have used the inorganic simulation extensively with thousands of students in our department at Brigham Young University. We have learned from our evaluation that: (i) students enjoy using these simulations and find them to be an asset in learning effective problem-solving strategies, (ii) students like the fact that they can both reproduce experimental procedures and explore various topics in ways t...

Instructional laboratory experiment on the effect of a ring baffle on the radiation from a small sonar transducer at an air–water surface

The axial pressure and directivity pattern in water were measured for a small sonar transducer at an air–water surface. The brass ring baffle placed around the transducer increased the axial pressure. For the directivity pattern, the ring increased the sound-pressure level at all angles except for those at midrange from the radiation axis where decreased levels were observed.

Instructional laboratory experiment on the effect of sound reflection on the driving-point impedance loop of a small sonar transducer.

This letter presents an experiment in acoustics to be used in a laboratory course for advanced undergraduate or beginning graduate students in physics or engineering. It describes the equipment used and the effect of reflection from a plate immersed in water on the driving-point impedance of a small sonar transducer placed at the air-water surface above the plate.

Instructional laboratory experiment on the sound field of a small ultrasonic transducer

The directivity pattern and the axial-pressure profile were measured for a small ultrasonic transducer. This is a useful basic experiment for an undergraduate course in sound or musical acoustics.

Instructional-laboratory experiment on temperature dependence of transducer impedance

An experiment for an advanced undergraduate or graduate laboratory in acoustics is descrived. The temperature dependence of the driving-point impedance curve of a hairpin magnetostrictive-stack transducer was measured in the temperature range 25 °C down to liquid-nitrogen temperature. Subject Classification: [43]85.20, [43]85.40; [43]10.85.

Measurement of the Velocity of Light Through μ0, ε0

An instructional laboratory experiment is described in which the velocity of light is determined using resonance in a series circuit of a standard inductance and a standard capacitance by measuring the geometric dimensions of the reactors and the frequency of resonance. With appropriate corrections to the simple formulas, an accuracy of about 1% can be achieved. This method is intended to clarify the physical basis of the measurements and the assumptions.