Every subsequent use of an engineering technique could be seen as a scientific experiment testing the validity of an abstract principle. It's just that by the time a principle gets to the engineering phase these experiments are no longer interesting - or they had better not be, anyway. (It would be very interesting if a bridge failed because the gravitational constant over that particular span of river were higher than in the rest of the known universe, for instance.)

Science explores the phenomenon and develops the principle. Engineering exploits the principle and provides a degree of diverse and rigorous demonstration of it. Edited to add: This process does not always occur in this order.