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The most common answer to the above question is — hot jet of gas comes out of the nozzle of the rocket engine at high speeds and as a reaction the rocket moves (is propelled) in the opposite direction [1]. But is this answer right? Let us explore what goes on inside a rocket engine and arrive at the right answer.
Laser radar, also called lidar, is proving to be a powerful technique for helping us to understand the world in which we live. It can provide information on topography, vegetation canopies, and on characteristics of Earth’s atmosphere. This article describes how laser light scattering can be used in lidar systems to help visualize the structure of our atmosphere and to address a wide variety of important...
Even elementary probability has a lot of interesting things to offer to the students to get excited and think about. Unfortunately our curricula are generally designed in such a way that interesting things are carefully left out. Even if the material is touched upon briefly, the discussion is reduced to simple calculation of ratios devoid of any meaning. In this article we discuss two interesting...
According to similarity property principle, structurally similar molecules tend to have similar properties. Similar molecules exhibit similar biological activities. However, there is no hard and fast rule that the compounds with similar chemical structure will have similar functions. There are several compounds of similar chemical structure with significantly different biological actions and activities...
This article deals with the timekeepers of the past, the sundials. Apart from discussing the structure of a few common sundials, we point out the reasons for the variation between sundial time and the time shown by mechanical timekeepers.
Mangroves, an exclusive group of plants with remarkable ecological importance, inhabit mostly the zones washed by the back and forth movement of tides. They are disappearing rapidly from their natural habitat due to various reasons. Mangroves create a unique ecological environment that is composed of rich assemblages of species. Economic importance of mangroves is also noteworthy.
We describe the connection between continuous symmetries and conservation laws in classical mechanics. This is done at successively more sophisticated levels, bringing out important features at each level: the Newtonian, the Euler-Lagrange, and the Hamiltonian phase-space forms of mechanics. The role of the Action Principle is emphasised, and many examples are given.
The 2010 Nobel Prize in Chemistry was awarded to three scientists, R F Heck, E-I Negishi and A Suzuki, for their work on “Palladium — Catalyzed Cross Couplings in Organic Synthesis”. It pertains to research done over a period of four decades. The synthetic procedures embodied in their work enable construction of C-C bond selectively between complex molecules as in simple ones at desired positions...
The ‘Green Classroom’ in the Botanical Garden of Ulm is an experiential learning forum outside school. Its educational concept is based on experimental learning and is geared towards expanding biological knowledge and developing positive attitudes towards small animals such as invertebrates and insects. The attitudes of 68 school students towards small animals, before and after they visited the ‘Green...
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