The following article is based largely on a new children's book called ''Alexander Calder and his Magical Mobiles,'' by Jean Lipman.
Alexander Calder was a famous artist who invented a new type of sculpture. You may think of sculpture as a solid shape that does not move, but Sandy, as his friends called him, had a different idea.
Sandy did not think that art had to stand still. So he experimented with the art of motion. He used motors for his first moving artworks, but he became bored with their predictable movements and got frustrated when the motors broke down.
So instead, Sandy began to make sculptures that moved by themselves. After he made a few, he asked another artist, Marcel Duchamp, what he should call them. His friend immediately said, ''Mobiles.''
Sandy Calder became famous all over the world for his wonderful mobiles. He made his first wind mobile in 1932, and made about 2,000 of them in his lifetime.
Some mobiles stand on the ground and some are attached to walls, but most hang from the ceiling. Their parts are carefully balanced and, when they move, they draw patterns in the air. Sometimes they look as if they are alive. You can see mobiles in homes and in public places like airports and banks.
''A mobile is a piece of poetry that dances with the joy of life and surprises,'' Calder once said.
He also made sculptures called ''stabiles'' that are almost the opposite of mobiles because they do not move. They seem to sit heavily on the ground, rooted and sturdy. But Sandy Calder's stabiles still have a strong sense of movement in their design. Many of his stabiles are found on open city plazas and in front of modern buildings.
''Stabiles and mobiles are like salt and pepper,'' Sandy said. ''They may be used together or separately.''
Calder was always a very happy man, and it showed in his artwork. He liked to use bright colors, especially red, blue, yellow, black, and orange. But red was his favorite color. ''I love red so much I almost want to paint everything red, '' he said.
Animals and the circus were his favorite subjects, but he was also fascinated with the sun and moon and stars. Many of his works were based on the system of the universe. Often, when you are not able to guess the subject matter of a mobile or a painting, the title will give you a clue to what Sandy was thinking about when he made it.
Although he is most famous for his mobiles, Sandy did many other things during his artistic career. After he saw the Ringling Bros. and Barnum & Bailey Circus for the first time, he made his own miniature circus complete with animals and performers. He and his troupe performed for over 30 years in Europe and the United States. Calder's Circus is now at the Whitney Museum in New York.
Sandy also created lively wire sculptures and jewelry, and he designed action toys, rugs, and stage sets. Toward the end of his career, he produced many paintings using gouache, an opaque watercolor. He even painted a race car and an airplane.
Whatever he did, his humor and playfulness showed through. He thought art should be fun to look at.
''Above all,'' he said, ''art should be happy.''
Alexander Calder had two homes, one in Roxbury, Conn., and one in Sache, France. When he was at his home in France, French children liked to play among the sculptures in the yard. Sometimes they would try to guess what the sculptures were meant to be - a bride's dress or a flock of butterflies.
When Sandy would hear their conversations he would say, ''All my greatest admirers are under 6.''
Maybe you will become one, too.
If you would like to read more about Alexander Calder and his work, you can send for ''Alexander Calder and his Magical Mobiles.'' For a paperback copy, send $7 ($15 for clothbound) plus $2 postage and handling, to: The Whitney Museum of American Art, 945 Madison Avenue, New York, N.Y., 10021.