Almost everyone travel everyday and you must pass any bridge along your way. Bridges are the connecting link between two lands separated with water body. Do you ever think how the pillars are build in the water bodies to construct the bridge?
Almost everyone must travelled in train. It is the most common means of transport. Trains are used for moving both passengers and goods from one place to another. We all know that train is run by a rail engine. Do you know, apart from energy sources, the most important thing to run a train is sand?
Most of you seen a wind turbine while travelling or while roaming at places. You see that 3 blades are there in wind turbine. Did you ever think why only 3 blades, and why not 4 or something else?
Did you ever think why airplane windows are round? Why not they are square or some other shape?