This study reports an undergraduate laboratory experiment that explores the temperature-dependent kinetics of caffeine release during tea steeping by using quantitative [superscript 1]H NMR spectroscopy with a water suppression pulse sequence. Designed for introductory organic chemistry laboratory courses, the experiment emphasizes the real-world…

Removing the pollutants from various wastewater is crucial to the environment, ecology, and humans. However, the pollutants are generally removed by chemical decomposition, which not only consumes a lot of energy but also produces carbon emissions. Electrochemical flocculation is effective to extract pollutant molecules and heavy ions from…

It may be asserted that there is no more effective deterrent to crime than the certainty of detection. Equally true is that there is no surer way to establishing identity than by fingerprints. The detection of fingerprints at the scene of crime is therefore one of the most powerful tools available in casework investigations. However, if the crime…

Water electrolysis, a well-known and simple experiment, confirms that a water molecule comprises hydrogen and oxygen atoms. In this experiment, hydroxide or hydrogen ions generated from each electrode were identified using an indicator based on the assumption that electrodes, electrolytes, and indicators do not participate in the water…

Recently, smart sensing/actuation paper has attracted significant interest due to its potential usage as a sustainable component in future electronics, robotics, and intelligent sensing devices. In acknowledging the importance of this topic for the engagement of students at the university level in conjunction with Industrial Revolution 4.0, it is…

Water electrolysis is used to teach important and fundamental concepts in chemistry. In practical water electrolysis experiments, it is difficult to achieve the ideal 2:1 ratio of hydrogen to oxygen. This work demonstrates an experimental setup comprising multiple water electrolysis cells connected in series to simultaneously visualize the effects…

The laser pointer has been widely used to demonstrate some simple optics phenomena, like reflection, refraction, total reflection, and diffraction. However, the rays of laser light cannot be seen in the air because the scattered light is too weak. Many physics teachers use milk or smoke to visualize rays of laser light in physics labs, but it is…

Water rockets can be used in a variety of ways, from schools to planetariums, with very young kids or adults. We propose here simple forms to work with water rockets, going one step further than a simple launch. A smartphone can be used to film the launch and analyze its motion with video analysis or it can even be attached to the rocket, using…

In the vicinity of a critical point, the impact of a substance's chemical identity is superseded by universal critical behavior for a number of physical properties, such as visible light scattering. In this classroom demonstration, students observe a single-phase critical mixture of partially miscible isobutyric acid + water (IAW) as the…

A standard physics experiment for students is to measure the terminal velocity of an object in air or in glycerine. A more difficult challenge is to measure the terminal velocity in water since the depth of the water needs to be large or the object needs to be dropped in the water at a speed close to its terminal velocity. Results obtained by…

Silver and its compounds have been widely used in experimental teaching, industrial production, and other fields. In these processes, a large amount of wastewater containing silver is usually produced, which might contribute to environmental pollution. Therefore, recycling silver from wastewater not only has good economic value but also meets the…

Apparatus catalogues of the first half of the 20th century contain a number of clever and simple devices for measuring the index of refraction of a liquid. In some cases students can put together one of these pieces of apparatus and then make their own measurements. The Gilley board was one of the devices that caught my eye, and I would like to…

In this paper a well-known experiment is considered that is used to demonstrate some aspects of water boiling. It is shown that the currently popular explanation is wrong and a better explanation is proposed, backed up with experimental data. Variations of the experiment are proposed that can be used for a more in-depth examination of the…

The physical problem of a body of water in a tank that drains through a hole in the base is a classical problem that has been studied since at least the time of Torricelli. To fixate this in a student's mind, one could ask them to visualize a bathtub that is being drained through the plughole or a bottle being drained through a tap. This problem…

The anomalous thermal expansion of water in the 0 °C-4 °C range is extremely important to life on Earth, but it is normally not presented experimentally in educational settings. This paper presents a simple experiment to explore the anomalous thermal expansion of water in the 0 °C-4 °C range and the heat exchange processes in natural bodies of…