How did Richard Strauss use clappers to create a whip-crack effect in Elektra?

In Richard Strauss’s 1908 opera Elektra, the composer utilized clappers—specifically a device known as a slapstick—to simulate the sharp, sudden sound of a whip-crack.1

A slapstick is an idiophone consisting of two flat pieces of wood fastened together at one end; when the two pieces are struck against each other, they produce a loud, percussive noise. By incorporating this instrument into the orchestral score, Strauss was able to achieve a realistic sound effect that punctuated the dramatic intensity of the work.231