Yahoo Real Estate Calculator Mortgage

Why is it more expensive for mortgage for a year, a 20-year mortgage in 10 years?
I used the Yahoo mortgage calculator Real Estate and calculates a mortgage rate of 10 years to 6.5% for $ 31,000.00 and gave me a monthly payment $ 352.00 $ 168.00, which has attracted interest. Then calculate as a 20 year mortgage at a rate of 6.5% to $ 62000.00 and he gave me a monthly payment of $ 462.00 $ 336.00, which has attracted interest. Why is it much more for the 20-year loan? I understand that the interest is higher in the highest amount, but should not payments are the same, because time the loan is twice as long?
In short, the longer you have to pay on a mortgage, plus interest on the loan to acquire, constant fear that you pay on a mortgage of fear that the interest on your loan to get.
Today’s Mortgage Rates: Which home loan is best?