Calder’s father and grandfather were both successful sculptors whose most famous public monuments can still be seen in Philadelphia. At first, the younger Calder began a career as an engineer when he graduated from the Stevens Institute of Technology in New Jersey.  Within a few years, however, he decided to devote himself to art. His first major success came in Paris during the late 1920s where his Circus of miniature mechanical ringmasters, acrobats and wild beasts made him famous among the avant-garde. At the same time, his innovative wire “drawings in space” stripped mass from sculptural form even as they still described portraits of individuals and celebrities. In 1930, while visiting the studio of abstract artist Piet Mondrian, Calder noticed various colored rectangles tacked to the studio wall.  He thought that the rectangles would be more compelling if they were made “to oscillate in different directions and at different amplitudes.” This led to Calder’s next invention, sculptures composed of moving parts. Marcel Duchamp, another friend and artist fond of overturning artistic conventions, proposed the term “mobile” to describe Calder’s radical sculptures.

Calder adapted many innovations central to modern sculpture at the beginning of the twentieth century to his own expressive ends. Rather than create sculpture by shaping masses of material, Calder used the planar forms of cubism that had been introduced by Picasso. Also, prior to the 20^th century, sculpture was not “constructed”; rather it was carved, modeled and cast. Calder employed workman-like materials and fabrication techniques, artistic innovations championed by artists of the Constructivist movement. Finally, Calder’s first motion sculptures used motors. When these proved unreliable, he began to create mobiles which offered a more elegant solution to the idea of motion in sculpture, and established a new interest among artists in kinetic art.

While considering these formal and technical innovations, one should not overlook the poetic quality of Calder’s work. Whereas sculpture (and all the visual arts) had traditionally addressed spatial concerns, Calder introduced the element of time into art. Grasshopper was created in 1947, the same year as philosopher Jean-Paul Sartre wrote about Calder’s mobiles in ARTnews magazine:
 
“…the objects always inhabit a half-way station between the servility of a statue and the independence of nature. Each of its evolutions is the inspiration of a split second. One sees the artist’s main theme, but the mobile embroiders it with a thousand variations. It is a little swing tune, as unique and as ephemeral as the sky in the morning.”