This video segment adapted from NOVA explains the difference between weather and climate and features groundbreaking analysis revealing that Earth's climate has changed much faster than previously believed. [5:48]

A sling psychrometer is used to measure humidity levels. Read about its history, how it works, its design, and how to use it. Includes a relative humidity table.

"Imagine a baseball dropped from an airplane flying at 30,000 feet; imagine that baseball reaching speeds of 120 MPH as it falls to the ground; and imagine you're under it!" How does hail form? How big can it get? Read more here about...

This site from the University of Illinois describes what air pressure is and how it is measured. Explains high and low pressure areas, isobars, and how pressure changes with height.

The innovative resource compares snow and ice cover in the Northern Hemisphere over a period of 24 years. The images are obtained from satellite measurements of visible and microwave radiation. The activity has an interactive online...

Students collect evidence to investigate erosion and deposition around the schoolyard.

Read about two types of rain gauges and how they work.