When a photon ( a very small increment of energy) encounters a substance one of three things may happen. (1) The photon may be transmitted -- it passes through without alteration. (2) The photon may be absorbed -- the photon never leaves the particle. (3) The photon may be scattered -- it's path may be altered.

Science in Children's Literature: Among the cornerstones of science are careful observation and accurate description. Like scientists, authors must also be careful observers. Mrs. Wilder's book presents a fine example in her depiction of the symptoms and treatment of hypothermia. Every time I read it I am more impressed with her scientific accuracy. It is worth starting early to develop skills at noticing what happens around you and at describing what you see.