What is the purpose of a nail compared to a screw?

A nail is a straight fastener driven in with a hammer; it goes in quickly and offers good resistance to shear (sideways) forces, making it common in framing. A screw has threads and is turned in with a screwdriver or drill; the threads grip the material and give much greater holding (pull-out) power and the ability to be removed and reused. Screws take longer to install but hold better in applications subject to pulling forces. Choosing nails for speed and shear strength versus screws for holding power is a practical fasteners concept on the Shop subtest.