what is the difference between transaction scope and normal transaction ?

using (System.Transactions.TransactionScope ts = new System.Transactions.TransactionScope())
            {
}

using (IDbTransaction tran = conn.BeginTransaction())
   {
       try
       {
           // transactional code...
           using (SqlCommand cmd = conn.CreateCommand())
           {
               cmd.CommandText = "INSERT INTO Data(Code) VALUES('A-100');";
               cmd.Transaction = tran as SqlTransaction;
               cmd.ExecuteNonQuery();
           }
           tran.Commit();
       }
       catch(Exception ex)
       {
           tran.Rollback();
           throw;
       }
   }