A simple, safe, and easy demonstration of the reaction of sodium peroxide with water is presented. The reaction is performed in a plastic bottle by adding water to sodium peroxide supported in a rubber "thimble"; oxygen is detected by the reignition of a glowing splint, while the generation of sodium hydroxide is indicated by…

To effectively demonstrate the transformation of ethanol into acetaldehyde, a simple, low-cost, and eco-friendly reaction demonstration was designed, in which a Y-shaped tube served as the reactor, condenser, and detector with the help of specific reagents. The ethanol was added via a transparent elephant nose spray bottle fixed to the top of the…

The formation of chemical patterns is in general difficult to control due to the random diffusive motions of the reacting chemical species in solution. In this paper, we present a new method using audible sound to control the formation of chemical patterns obtained in blue bottle experiments. The waves generated on the surface of the solution by…

A 2.7 m long stringless pendulum was set up to measure the coefficient of rolling friction of various balls, at higher rolling speeds than usually observed with a short stringless pendulum. The arrangement is easy to set up and makes an impressive classroom demonstration as well as an interesting laboratory experiment.

Under most conditions, a liquid mixture does not have long-range structural order and may be considered to be a homogeneous collection of molecules in random motion. However, if a single-phase critical mixture of a partially miscible liquid--liquid system is subjected to a small temperature jump into the two-phase region, then structural coherence…

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…

In the vicinity of a critical point, the impact of a substance's chemical identity is superseded by universal critical behavior for a number of physical properties, such as visible light scattering.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…

Potassium tris(oxalato)ferrate(III) trihydrate is a commonly prepared coordination compound in general or upper-level chemistry laboratories and can be recycled to grow large single crystals that instructors may display when introducing the experiment to classes. Showing the crystal's shape can also be used to briefly introduce students to X-ray…

This paper takes a new look at a well-known physics demonstration--the Cartesian diver. A general overview is provided as well as some new twists on the old classic. A new version is proposed that can demonstrate some of the finer details of scuba diving. A hydrodynamic method of lifting sunken divers is presented.

Poinsettia ("Euphorbia pulcherrima") contains anthocyanins that dissolve in water and exhibit color changes due to changing pH. This property makes the poinsettia extract a useful acid-base indicator for pH demonstrations. When combined with common household materials, this experiment can be used as an alternative low-cost tool in…

Herein, two simulated electrochemistry experiments, namely, the (i) electrochemical series, using an electronic half-cell module, and (ii) citrus fruit battery series are demonstrated for undergraduate chemistry students. The demonstration can be performed for in-person and remote students by connecting the electronic half-cell module to a…

The use of red cabbage ("Brassica oleracea var. capitata F. rubra") extract as a pH indicator is a versatile and popular demonstration that is employed by educators in many schools and universities. Previous variations of this demonstration have used red cabbage extracts to prepare paper that changes color when solutions of acid or base…

Students encounter antioxidants in many areas of their daily life. Antioxidants play a crucial role in cosmetics, in nutritional or dietary supplements, as additives for the preservation of food, and as a natural component in fruit and vegetables. Accordingly, antioxidants are believed to promote health through the prevention of oxidative stress…

Sound is an interesting topic for physics lessons at all ages. However, it is difficult to illustrate this ubiquitous phenomenon and many models do not adequately represent the properties of sound and thus promote unwanted conceptions. The experiment presented here avoids this by visualising sound itself with the help of the schlieren technique.…

Using Tracker, a popular video-based physics modeling tool, the position-time data of magnetically damped oscillations of a simple pendulum are acquired. Eddy currents are generated on an aluminum sheet as the magnetic pendulum bob passes over it and the induced magnetic field opposes that of the magnetic bob. This causes the damping. A…