This interactive activity from the NOVA Web site challenges you to think like Einstein and understand how time travel might be possible.

This video from NASA explains the process by which gamma-ray flashes associated with storms produce matter/antimatter particle pairs.

Four unit plans provide opportunities for in-depth explorations of important foundational climate concepts -- weather, water as a solid, liquid and gas, and the water cycle -- that are appropriate for K-2 and 3-5 learners. These unit plans incorporate many of the lessons highlighted in other articles in this issue of the online magazine Beyond Weather and the Water Cycle. The magazine is structured around the essential principles of the climate sciences.

Diffraction is the bending of light waves around the edge of an object.

According to the law of reflection, the angle of incidence, which is the angle at which light strikes an object, is equal to the angle of reflection, which is the angle at which light bounces off an object.

In this interactive activity adapted from the University of Utah's ASPIRE Lab, learn how to measure wavelengths and see how wavelength affects the color of the light that we see.

Refraction occurs when waves change direction as they move from one medium into another medium.

Students will witness their classroom with all lights and electronic devices/equipment turned off. They will investigate the impact and then build a simple circuit with a battery and light.