IUCAA - Khagol # 111 - July 2017

| KHAG L | | No. 111 - JULY 2017 11 The demonstrations on optics made them experience and realize the behaviour of light when it interacts with different media. Working principle of different telescopeswas one of themost enjoyed sessions. Hands-on astronomy included the making of an angle measurer, a CD spectroscope, a solar camera using pin-hole principle. There were three experiments designed to improve the experimental skills of students. These were (i) measuring the diameter of a mustard seed, (ii) finding the height of the Samrat Yantra at IUCAA using trigonometry, and (iii) determining the ratio of sun’s distance from the earth to the diameter of the sun using a solar camera made by students. Apart from the standardmethods, the students were allowed to come up and use their ideas to solve a given problem. This encouraged the students to think about the different ways to carry out an experiment. For example, in the case of finding the diameter of mustard seeds, many students used volume-displacement principle. For determining the height of the Samrat Yantra, students used kinematical equation by measuring the time taken for a pebble dropped from top to reach the ground. In the third experiment, where an astronomical constant was to be calculated, the students came up with the ideas of projecting the image of the sun. Students also learned about the limitations of different methods, and error factors. On the last working day of every week, the students submitted reports of the experiments done by them. At the end of each week, sky-watching sessions were organized for the participants and their parents. In these, the students used their sky-map reading knowledge gained during the week to locate the stars and constellations practically in the sky. On May 12, 2017, Zero ShadowDay for Punewas also celebrated. Students were also given an opportunity to interact with IUCAA faculty members. Somak Raychaudhury, Durgesh Tripathi, Aseem Paranjape, Sanjit Mitra and A. N. Ramaprakash spent some of their valuable times to answer the questions of the students in a friendly manner.