What is the difference between Dominant and Recessive alleles?

Alleles are different forms of a gene. For exanple if the gene is eye colour, the alleles would be the different colours (green, blue, brown) For every gene that you have, you get two alleles, one from your Mum, and one from your Dad. The dominant allele is the one that gets expressed (is shown) for instance if your Dad passes on the allele for green eyes and your Mum passes on the allele for blue eyes. The dominant one is the colour that your eyes are, eg blue. The recessive allele is still there, it just isnt shown.