Time is pretty complicated. What is a second, how can you describe a second? It's a bit like a metre, you can't really explain how long a metre is. How about a kilogram, what actually is a kilogram?br br Firstly let's start off with time. What is a second? For most of us a second is how long a clock tells us a second is. Trying to explain to someone what a second is hard. Try think about what a second actually is without using a stopwatch or clock -- it's quite hard.br br Music: (Pull Up Your Jeans by It Takes Two To Tango).