Engineers design new objects through the use of computer models, but in the end they have to verify that all the calculations produced the result they expected. That means testing the product. In the case of, say, a new carbon fiber aircraft wing, you bend it until it breaks and see what happens.

Boeing just did that with a 787 Dreamliner wing and they have a video you can watch at:

http://787milestones.tpninteractive.com/

Thanks to the outstanding c0t0d0s0.org blog for the tipoff via Twitter.