Interest Rate is a kind of what you will get for Investing your money in a bank .. when this percentage of compound interest either it was 1 % as in US or around 4 % as in Australia is left for years it will transform into huge amount of returns .. 

The concept of Compound Interest may seem like a long way investment but numbers don't lie anyway .. my note here is that we don't know after 50 years for example what will be the situation for  Inflation which reflects the real power of money purchasing capability .. watch the following video and just think about it ..