Learn about snow--how snowflakes are formed, why they fall, if each snowflake is really unique, and other facts. Also learn about Wilson A. Bentley, the first person to photograph an individual snowflake.

An introduction to time discusses the inventions and communication used to tell time throughout history, including hour glasses and atomic clocks to calendars and chronometers.

"How do you weigh a panda? Or check a sea lion's tooth? Or figure out why a llama is limping? These are just some of the many tasks veterinarians, technicians, and animal keepers at the Smithsonian's National Zoo are trained in. With full-color photos and lively, accessible text, this new title looks at the very busy "to do" list of zoo workers as they take care of their creatures large and small."--