Dorothy Brogan, Age 11, of Staten Island, N. Y., for her question;

What is Metamorphosis?

When a magician turns a fluffy bunny into a white winged dove, we know it is just a trick. Nature turns a fish into a frog and changes a grubby worm into a velvety ¬winged moth, but these are not tricks. The earth changes gritty crumbs of limestone into smooth, gleaming marble, and this is no trick. These magic changes of nature are metamorphosis.

Metamorphosis and metamorphic and metamorphism are impressive words and pleasant to pronounce. They are all coined from a Greek word meaning to transform. When something is transformed, it is remade, changed and reformed. By metamorphosis, a caterpillar becomes a butterfly, a fishy tadpole who must live in the water becomes a sun bathing frog.

There is no metamorphosis in the life of a cat. A fluffy kitten is a miniature copy of her parents, and she changes only by growing bigger. But a glamorous lone moth lives through four entirely different life stages. She starts out as a little egg, perhaps on a hickory leaf. This is the embryo and stage one of her life. The egg changes into a chubby green caterpillar, dotted with rows of red buttons. This is stage two, the larva.

The larva changes into a brown, silken cocoon. This is stage three, the pupa. The cocoon changes into the green, swallow tailed moth with glimmering wings. This is stage four, the imago. A creature that develops through four different forms is said to go through a complete metamorphosis. Moths, butterflies and many other insects experience complete metamorphosis.

Frogs go through incomplete metamorphosis. The egg becomes a fishy tadpole which becomes an air breathing frog. Toads and salamanders also go through 3 complete metamorphosis.

Metamorphism, strange to say, takes place in the restless crust of the earth. Forces in the earth's crust make chemical minerals into assorted rocks. Some of these rocks are later transformed into entirely different rocks. Layers of muddy shale became hard plates of brittle slate. The minerals in limestonee are recrystallized into waxy marble. Gritty granite is transformed into dense and mottled gneiss. These remade rocks are called metamorphic rocks.

The forces which metamorphize rocks are very powerful. The temperature of volcanic activity may be needed to change carbon to crystal diamonds. Granite may be changed to gneiss by the tremendous weight and heat of a growing mountain. The shock of a meteorite's fall may metamorphize the very chemicals from which it is made.