 The year 2015 is very special for physics. It is the centenary year of Einstein's General Theory of Relativity. Regarded by many as one of the deepest creations of the human mind, the year 2015 is also special for another reason. For in July this year, physics students and teachers from all over the world had converged to Mumbai to participate in the world's most prestigious annual competition in physics, the International Physics Olympiad known for short as the IFO. The 46th IFO was held at Mumbai, India from the 5th to the 12th of July 2015. The event was organized by the Homi Bhabha Center for Science Education, a national center of the Tata Institute of Fundamental Research Mumbai, an autonomous institution aided by the Department of Atomic Energy. The 46th IFO was supported by the Government of India through the Department of Atomic Energy, the Department of Science and Technology and the Ministry of Human Resources Development. Now at the plus two level the Olympiads are a major program of the Homi Bhabha Center and here our approach in the Olympiads is towards problem solving, towards creating new ways of looking at the regular science in an innovative way which makes the students think go beyond the normal mundane textbook kind of science to look at the world around them and to focus on problem solving both theoretical as well as experimental. And these are all non routine problems and this is the kind of thinking that we would like to expose students to, all students. Preparations for this mammoth event began at the Homi Bhabha Center for Science Education, the HBCSE, more than a year ago. The most important one was of course the academic part because the host country is responsible for preparing the tasks of both the theoretical and experimental components of the competition. So we started this work nearly 18 months in advance that is in the early 2014. We formed an academic committee constituting of scientists and researchers and teachers from various institutions across the country. We also listed the help of a bigger academic team of nearly 100 people who were mainly teachers and researchers in various institutions and they worked tirelessly for the next 18 months to prepare these tasks. The second level of preparation was the administrative one that is to gather the funds to invite all the countries and to arrange for their travel to India. The third part was the logistics of the event which were indeed enormous because this included the hospitality of nearly 1000 people in the city for 10 days, the conduct of the examination for 400 students and their excursions and the transport. For all this the staff members of the Homi Bhabha Center for Science Education worked relentlessly to make this as present and experienced as possible for the participants of IFO 2015. The 4th of July saw IFO participants from all over the world arrive in Mumbai. The arrivals from 83 countries continued for more than 24 hours and several dedicated teams of volunteers posted at the Mumbai airport made sure that they had a hassle free arrival in India. The contesting students were put up at the Leela and the teacher leaders and scientific observers at the Taj Land's End. This was done as per the Olympiad's established practice to segregate the contestants from their leaders. They could not meet or communicate with one another until both the experimental and theory exams were over. To stay in a foreign land, each country team of five students were looked after and escorted by one student guide during the entire duration of the Olympiad. Nearly all of these guides were undergraduate students from Mumbai and Pune. Similar student volunteers helped the leaders and the organizers at the Leaders Hotel as well. Checking in was followed by registration. IFO kits were given to all participants containing all the necessary information including the event schedule. Registration continued from the morning of July 4th to the evening of July 5th to keep pace with the staggered arrivals. On the 5th of July, all roads led to the Tata Institute of Fundamental Research. The opening ceremony was to be held at the Hermibaba Auditorium of TIFR. The long ride to TIFR gave the participants an opportunity to view the Mumbai skyline as well as the famous sea link here. IFO 2015 was inaugurated with a ceremonial lighting of the land by Dr. R. K. Sinha, Chairman, Atomic Energy Commission. The aim of IFO is to celebrate physics at its best by posing challenging theoretical and experimental problems to the most meritorious pre-college students from around the world. But there is a greater cultural aim that is to promote friendship and cooperation among students and teachers transcending boundaries of nations and continents across the globe. Organizing any IFO is a huge and demanding undertaking. The 46th IFO was the largest physics competition ever held with 382 students, 160 mentors, 76 scientific observers and 18 guests from 83 countries around the world. The organizers had to prepare theoretical and experimental problems each of the highest order confirming to the most exacting standards of accuracy and precision. Besides this academic dimension, the event was also to include excursions and cultural programs to expose the visitors to the culture and heritage of India in the short span of a week. Formally declared, this 46th International Physics Olympiad opened. The cultural program that followed gave the international audience fascinating glimpses of India's rich tradition of dance and music. The Olympiads have a potential to impact educational systems and attract students to science careers. That's one part and another part is that those who participate in the International Physics Olympiad, that's not only true for the Physics Olympiad, it holds for mathematics, chemistry, etc. too, is that it's very stimulating for the students. You will see that when you followed them now during this week that since they meet their peers from all over the world, there's the same fascination for science as they have. It's very stimulating. There are high school students at the almost last stage, so they are choosing now what to do further on, what will be their career. And for sure, for really most of them, this is a boost to continue in either in physics or in science in general. So I think the impact of the Olympiad, any Olympiad, is big. IFO is a tradition that began about half a century ago in 1967 in Warsaw, Poland, with an initiative taken by Professor Waldemar Goszkowski. The International Physics Olympiads have been organized in a different country every year ever since. Originally back in the 60s, the IFO was instituted as a competition between education systems. And so the students would represent their countries and their country's education and their country's schools. And that's still the case, but increasingly many countries have some training program for their students, of course, and also no longer does this style of competition reflect how many schools operate and how many schools are teaching physics. And so as they become more and more different, I think there will be some changes. And this very year we have a proposal to make significant changes to our syllabus. And that's along these lines to add some of the more modern physics that's come in. So it allows us to ask some questions which are more exciting to students who are seeing more interesting things in their schooling than they used to see. I think that's a real challenge. July 6. In anticipation of their first test, scheduled the next day. This was a day for the students to relax. They visited the Nehru Planetarium and caught a riveting sky show. Many of the students were visiting a planetarium for the first time and were truly awed by it. More joy was in store when they reached the Nehru Science Center and discovered the many wonders here. While the students were having a gala time, the international jury consisting of teacher-leaders and scientific observers from all participating countries were involved in the grueling task of critically deliberating on and approving the next day's experimental test problems prepared by the hosts. This was the first time ever that the experimental test was being held before the theory test. This is the year of light and we use laser light and look at diffraction and use diffraction of light to study and find out why for example or how Rosalind Franklin figured out the double helix structure of DNA just using diffraction of light from a spring. Also we use diffraction from little ripples, surface tension waves on water to determine the mechanical properties of water using light to determine mechanical properties. So these are really exciting experiments. We'd like the children to go home even if they didn't get the entire calculations correct or all their graphs correct. The important thing is they should go home and feel like, wow, that was a lovely experiment to do. They should learn something out of it and say, yeah, this was cool. Finally, the day of the experimental test dawns, 7th July. The logistics for this enormous exercise were a nightmare for the organizers. The students arrive at the venue all charged up. While most were excited about the next few hours, a few decided to relax and save their energy for the actual experiments. If designing the test problems was difficult, setting up the more than 400 cubicles for carrying it out was no easy task either. But now it's all done and the test is underway. To the greater relief and satisfaction of the organizers, all goes well without a hitch. The biggest challenge in arranging and conducting the examination was making sure that each student gets exactly the same kind and setup of experimental apparatus. So each setup was tested for a specific set of adjustments and we took data on each setup before we gave the setup to students for the competition. So we had a team of about 56 academic members who worked hard for 3 days at the examination venue before the examination. Who actually tried setting up the experimental apparatus. They took the data, sample data, we checked the sample data and we checked the sample results and only then we handed over the experimental area, the cubicle to the student for the examination. After the exams, the students were treated to a show of gymnastics and traditional Indian acrobatics known as Malcolm. The unique sport demands extraordinary control and balancing technique on a wooden pole or with a rope. Some of the participants tried their hands at it after the show was over and discovered that some things can be as much fun as physics and as difficult to master. And while the students appeared for the test, it was time for the leaders and observers to relax and take a trip downtown. The architecture of yesteryear's Bombay fascinates the scientists as much as the street food of today's Mumbai. Come the next day, the 8th of July and the roles are reversed. The teachers and leaders are now busy discussing and finally approving the theory problems set up by their Indian hosts while the students have a day to relax. They have a great time visiting the same sites that their seniors did the previous day. The students have begun to mingle now and new friendships are forming. This of course is one of the aims of the whole event. Such friendships not only enhance their interest in physics but can also generate collaborations when they mature into scientists of the future. The walking tour is followed by a visit to the Tata Institute of Fundamental Research. This to most students is their idea of paradise. They are like children in a candy shop just can't get enough of anything going from one research laboratory to another. But the next day is another anxious day for the students, a theoretical exam. The idea behind theory questions and IPHO was that the question should not only test the physics knowledge or skills of the student. But after I took in the question, the student should feel that they have learnt something new, something exciting. So for example, the first question was about the sun. And the students actually could determine the temperature of the surface of the sun while looking at light coming from the sun. And they could figure out how to measure the temperature of the core of the sun while looking at neutrons that come from the sun. In this process, they also calculated the efficiency of a solar cell. The second question dealt with overarching principles in physics called as the principle of least action or the extreme principle. Now this is applicable in a wide variety of cases. Starting from classical mechanics to optics to wave mechanics or quantum mechanics. And the topic that the students actually did in this, were dealt all the way from format to an electron experiment that happened only in the last decade. The third question was a very different variety. Here the students went step by step into finding out design parameters of a nuclear reactor. Now simply by knowing some basic facts about thermodynamics, it was amazing that one could actually determine these parameters which are very close to what are there in the actual nuclear reactor. So when the students came out of this exam, the feedback that they got from them was that they did get exposed to physics starting from very fundamental to very applied. And they just loved this one. The best young talents in physics from all over the world have gathered here today. Once again, some decide to approach it with a relaxed frame of mind while others want to utilize every second available to prepare better. And once again, the test goes by without a hitch, taking a great load off the minds of the organizers. The leaders and the observers meanwhile are visiting a historic site in Mumbai, the Kanheri Caves. One of the finest examples of Buddhist art. These caves are truly breathtaking. Today, they also get to experience the famous Monson Rains at last. In almost every country, students are selected for the Olympiad through a multi-level screening process. In India, there is a three-tier selection procedure. About 40,000 students appear for the first level test in physics held across the country by the Indian Association of Physics Teachers. About 300 students selected from this test go through a second level test conducted by the HBCSE. The best 35 of these go through about two weeks of training at HBCSE, after which the best five students represent India at the International Olympiad. Since HBCSE, the Homi Bhabha Centre for Science Education, was the organizing institution of I4 this year. In accordance with the Olympiad Convention, the selection and training camp for physics was not held at the HBCSE this year. The camp was organized by the Indian Association of Physics Teachers at Khalsa College at Delhi in June 2015. 10,000 students participated in the first year, like 98. Now, over 50,000 students around India have participated in the first level competitions. So, there has been growth in terms of students, there has been growth in terms of medals that we are getting. There has been growth in terms of our position in the International Olympiads. And finally, the Olympiads have brought a very important element into this country's education system and that is experiments. In all exams such as the IIT, JEE exam, there is no experimental component. The Olympiads is the only competition in India where you have an experimental component as much as 40%. With both the tests behind them, it was time to have fun on the next day, the 10th of July. The students visited the biggest amusement park in the country and experienced they are not going to forget in a hurry. The experience here was amazing, the excursions were really fun and we got to see the culture of India, meet the participants and have a lot of fun. The best thing was probably getting to meet so many other countries and the getting to share experiences with them and sharing a common interest in physics with so many different cultures. I love Mumbai very much, especially the people and the environment because the people here are very friendly, kind and polite. In the meantime, the leaders and the observers visit the Gaudrij lock factory, their last excursion before the hectic end phase of the competition. The toughest leg of the IFO awaits the leaders as they head back. They now have to evaluate the answers given by their students in both their theory and experimental tests. The organizers too need to grade the answers scripts of all the contestants. The 120 graders brought in from all parts of the country have a daunting task ahead. Checking nearly 400 experimental answer sheets within two days and an equal number of theoretical answer sheets rigorously in even less than a day. One of the biggest challenges of international Olympiads is that as many as 30 languages are used for these exams. This involves getting the question papers translated into so many languages, a task carried out by the leaders. But the questions must be designed in such a way that the answers are purely numerical or graphical so that they can be evaluated by the host country as well by passing the language barrier. A large set of graders for the 46th IFO included professors from IITs, universities, national institutes, college teachers and also a large number of undergraduate students who were past Olympiad participants. The graders went through several training workshops prior to the event. Extreme care was taken to see that the evaluation was consistent and accurate. Once the grading is over from both sides, the hosts and the team leaders, there still remains a crucial last step that makes the Olympiad a truly democratic and transparent event. The organizers arrange an arbitration session where team leaders from all countries are given an opportunity to discuss and clear any doubts they may have with the examiners on the scores of their students. The scores after this session become the basis for medals and prizes. We've had so many physics, so much physics discussion that it's just enriched me. And even in this visit when I came for the exam, it's not just the physics, there is also a lot of cultural exchange. For that matter physics itself and science is also part of culture and meeting people from all over the world and talking with them. Not just about physics, about other things, language and cultures and all that. It's also been very enriching. While the seniors sweat over the assessment, students have another fun trip. This time to the vehicle factory of Mahindra and Mahindra, the organizers had made sure that they have as varied an experience as possible within the short span of their stay in Mumbai. After all, the students are what IFO is all about and no effort was spared to make it a rich and memorable experience for them. A remarkable feature of the whole event was the bringing out of a daily bulletin titled Reflections, which would report all the activities and fun of the preceding day of the Olympics. This is an international event which brings prestige to the country because if your students do well, definitely it adds to the prestige of the country. Also it exposes Indian students to international situations. The experience is not only important for the students but also for the organizers. And in a way it has happened this way and that was also the government expectation that these examinations that the country conducts or the program the country conducts will really boost teaching of that subject in the country. Because it will set up a benchmark on the one hand and on the other hand it will prepare teachers and students. Finally, it's D-Day. The 12th of July is the day of reckoning. The entire cluster of students, leaders, observers and guests have gathered at the Indian Institute of Technology, Mumbai for the closing ceremony. It has been a 24-7 job for the organizers ever since the participants started landing in Mumbai until now when the results are ready to be declared. Only slightly less stressful were the 18-month long preparations before the event actually began. The Homi Baba Centre for Science Education did a splendid job bringing laurels not only upon itself but upon the country as well. I'm very glad that the International Physics Olympiad hosted by our country this year has been a stupendous success. Actually this program, the Physics Olympiad program started some 17 years ago and has been going from strength to strength ever since. I would like to congratulate all the young scientists of the Physics Olympiad said as well as all the administrators and organizers at the Homi Baba Centre for Science Education for bringing honour to our country. And now everyone's heart beats a little faster as the awards are announced. There are honorable mentions, bronze medals, silver medals and gold medals. The honorable mentions and the bronze and silver medals are awarded by a number of distinguished people associated with the Olympiad. The gold medals were awarded by Dr. R. Chidambaram, Principal Scientific Advisor to the Government of India and Chairman, Scientific Advisory Committee to the Cabinet. The award for the best overall performance and best performance in the theoretical task go to Taeyong Kim from the Republic of Korea. The award for the best performance in the experimental task to solve Kim from the Republic of Korea again. And that for the best performance among female participants, Dinti Hongtao from Vietnam. This year some of the best performing teams came from China, Korea, Chinese Taipei, USA and Russia. The Indian team secured four silver and one bronze medal. Science is now going global, collaborations are increasing, mobility of scientists is increasing and the interactions that they start now will be very beneficial to us in the long term. And also the more and more young people will get interested to participate in the Olympiad. Because what India needs now is to have talented young people, talented in science, to have careers in science and we should do everything possible to retain them there. For that of course we have to do a lot of things but one of the main roles is can come from this kind of Olympiads. The next IFO is going to take place in Switzerland. As the Indian organizers handed over the IFO flag to their Swiss counterparts, the Swiss team screened a small teaser showing us what to expect from IFO 2016. And one must say that it must have inspired the 700 strong audience to already begin preparing for the next year. I think that we sometimes forget that it's not just getting them interested, which is important, but also that those who are interested, they must have challenges and possibilities to meet other with the same interest. In China, if the students goes to the final step that I mean for the last 50 students who qualified for the next choice for the IFO and IFO, then they have the right to go to the universities directly. In Nigeria we don't have, we've not had any female student, some countries I see some female, in fact I've seen a female student get a gold medal. I'm looking forward to the day when we have a female student participate in the International Athletes Olympics. I found it very interesting, also the organizing committee did its best, also the problems are of great level, the experiment was very interesting. I think it was very interesting for me and I learned a lot. And thus the 46th International Physics Olympiad came to a close, but the Olympiads will go on from one venue to the other, year after year, more important. Physics will continue to appeal to curious adventurous minds the world over as it did in the past and as it will for generations to come.