Murray Gell-Mann, who passed away at the age of 90 years was a giant of modern particle physics. His most well-known contribution is the proposal that protons and neutrons are not indivisible but are made up of smaller particles called 'quarks'. The complete story of strong interactions of which the discovery of quarks is only a part and which is intimately connected to Gell-Mann's work is presented here in an elementary manner.

Sir Henry Hallet Dale can undisputedly be accoladed as one of the greatest British pharmacologists of the twentieth century. His work was pivotal in laying down the principles of chemical neurotransmission. This article gives some account of Dale's life and his most important discoveries, including the identification of acetylcholine as a neurotransmitter in the autonomic and somatic nervous systems.

Educational psychologists have developed theories of learning based on three main paradigms -- behaviourism, cognitivism and constructivism. Behaviourists believe that the behaviour of learners is a response to their past, and behavioural modification is the main purpose of education. According to cognitivists, the behaviour of learners is the result of his/her cognition, and the main aim of education is to change the cognitive schemas. Constructivists, on the other hand, believe that learners construct their own knowledge, and the objective of education is to provide opportunities to gain knowledge. The understanding of how children acquire knowledge has influenced teaching-learning processes in the classroom significantly. The role of teachers has changed from the person imparting information to a person facilitating the construction of knowledge. Teaching science has also been influenced by the changing psychological ideas about teaching and learning. The information age that dawned in the 20th century necessitated the acquisition of information through informal modes like listening to the radio, watching television or surfing the world wide web. Developments in digital technology have, thus, changed the way students make meaning of given information. All these changes have forced the educationists to design appropriate methods of teaching and learning. A journey into the changes that learning theories have witnessed influencing the teaching of school science is outlined in this article.

The theory of spherical tilings is an interesting and fruitful field, attracting, among other researchers, mathematicians. It is a transverse topic crossing several mathematical areas such as geometry, algebra, topology and number theory, but it is also an object of interest for other scientific fields such as chemistry, physics, art and architecture. Here, we make use of GeoGebra to establish some results, describing a class of monohedral spherical tilings and inferring some conjectures. This will highlight how the use of this software has been crucial for the construction of new knowledge in mathematics with applications in different areas of engineering.

In this article, I will describe experiments designed to understand how ants estimate the distance they have walked. They rival in their simplicity, the experiments described in my previous article, designed to understand how bees estimate the distance flown. Although ants can also use optic flow to estimate distance, in the absence of optic flow cues and of pheromone/chemical trails, as may sometimes be the case in the desert ants, \emph{Cataglyphis}, ants estimate the distance walked, not by the energy expended but, believe it or not, by `counting' (or integrating) the number of steps they have taken. This was proved by showing that ants on stilts (elongated legs) overshot the required distance to return home while ants on stumps (shortened legs) undershot the required distance.

Both, human appreciation of music and musical genres transcend timeand space. The universality of musical genres and associated musicalscales is intimately linked to the physics of sound, and the specialcharacteristics of human acoustic sensitivity. In this series ofarticles, we examine the science underlying the development of theheptatonic scale, one of the most prevalent scales of the modernmusical genres, both western and Indian.