Let's say that today you can buy in a pub 4 pints of beer with a £10 note. (Yes you can get 4 pints for a tenner here up North!). Tomorrow the government prints and distributes to all the population sufficient £10 notes to double the number of £10 notes in circulation, in order to make everyone look richer and buy more votes. Nothing else has changed, i.e. no new riches have been discovered but you now have £20 to buy your beer, an amount that you think should buy you 8 pints.
Wow isn't that great that they can just print double the money and make us all twice as rich? I'm going to have a real good night out BUT...
No. The government has printed double the money, but it hasn't been able to print double the water, hops, yeast and grain needed to make double the beer, because these are real commodities that require more than just printing to obtain.
So, the pub landlord won't give you double the beer just coz you've got an extra printed £10 note, or he would run out of beer, because his amount of beer hasn't doubled like the money has. Therefore he has to double the price of the beer to keep up with the devalued (diluted) currency and keep his stocks correct.
That's how inflation works; welcome to fiat currency Notch.