The Coins

You are blind-folded and told that there are 50 coins neatly arranged on a table before you, in five rows of ten coins each. You are also told that exactly ten of these coins show heads. You are asked to convert this single group of coins into two groups such that each group shows the same number of heads. How can you make this happen? (Assume that you are unable to feel any difference in the coin's two surfaces.)