Dhruv made a classic experiment, a Cartesian Diver, and explained the functioning and concept confidently and succinctly; something that thoroughly impressed the judges. It is a beautiful experiment that shows off a couple of principles: Pascal’s Law, which says that the pressure change through a fluid is transmitted equally throughout the fluid AND that air is more compressible than water, hence it is the air in the balloon or dropper that gets compressed, reducing its volume (hence increasing its density) and allowing the balloon – suspended with weights – to sink in the water.

It is often said that the simplest experiments are also the most beautiful. Arin exemplified that statement by simply showing that placing a powerful magnet (neodymium magnet) very close to the surface of the water creates a wee bit of a trough in the water, due to the “Diamagnetism” of water. If there is a small floating object in the water, e.g. a piece of metal foil, which is non-magnetic, it keeps wanting to be within this trough. So moving the magnet over the surface of the water makes it look like the piece of metal foil has suddenly become magnetic as it seems to follow the magnet! Arin narrated to us that he discovered this while once playing with a magnet sitting in the bathtub! Talk about a eureka moment!

Soham is clearly also a budding musician; not just a scientist! With a winning smile and oodles of enthusiasm, he made and showed off his wonderful “dholak”, a percussion instrument, made with some balloons as the vibrating membranes and rubber bands to help mount on a cylinder. He also added some string to the contraption, so he could hang it around his neck and bring a flavour of Folk India to the occasion! Rock on, Soham!!

Gokulraj used his ingenuity to come up with a model to show how rainwater could be harvested, and used through a series of bottles and pipes (straws) to power turbines to generate electricity. Using both tidal and flow-of-water energy, this could be a model for small-scale energy generation done at home by all, especially in rainy areas.

Kavin made another classic model: a homopolar motor. Though inefficient, it is a wonderful model showing how you can make a motor without a coil! How marvellous! The surface of the magnet itself acts as a coil, and so rotates rapidly as current from a battery is passed through it. Kavin had all the judges spinning in a tizzy when he showed this off.

Dhaatri made a variation of a classic toy, the cup phone. In this case, instead of paper cups, Dhaatri used small plastic containers (urine sample containers!), and connected them with string to come up with her creation. A more ear-sized opening meant that less sound was lost in transmission. The youngest winner is already preparing for a future of congratulatory phone calls!