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.

Blue (B), yellow (Y), red (R), and green (G) color-changing dye was used in a general chemistry course for first-year undergraduate students with nonscience majors to highlight the redox reactions written as the gain and loss of hydrogen. The first experiment is a vibrant color variation using a synthetic dye of indigo carmine. The second…

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…

A hula hoop rotating around a person's waist is an example of circular motion where the centripetal force on the hoop is directed towards the centre of the circle rather than the centre of the hoop. The friction force on the hoop is relatively small by comparison since the hoop rolls around the waist. A slight complication is that the hoop rotates…

This study explored the impact of interactive e-books on the viewing behaviors of children in science demonstrations at museums. To conduct this study, an interactive e-book on a pendulum experiment was developed and integrated into a physical science demonstration at a museum. Two scientific demonstrations were conducted in this study. The first…

To present the difference in oxidizing strength in concentrated and dilute nitric acid reacting with copper, a simple, facile demonstration of these reactions is designed using a waste plastic bottle, plastic droppers, and syringes, which are costless and easily assembled. This new version can be used to demonstrate the difference in oxidizing…

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…

The main objective of this intervention study was to investigate the effect of three teaching approaches, namely the traditional teaching method (TTM), a teacher-based demonstration experiment (TBDE) and a student hands-on experiment (SHE), on students' academic performance. A total number of 324 senior five students studying chemistry as one of…

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…