The earliest scientists first observed the waves that earthquakes produce before they could accurately describe the nature of earthquakes or their fundamental causes, as discussed in Lessons 1–5.

For decades, physicists searched in vain for evidence of gravitational waves, the stretches and squeezes in spacetime that were first predicted by Albert Einstein’s theory of general relativity a ...

A sound wave is a vibration that travels through a solid, liquid or gas such as the air or water. A loud sound has a large amplitude, a high pitched sound has a high frequency. Musicians and ...

Waves transfer energy from one place to another. Light from the Sun travels through space and through the atmosphere, transferring energy to the Earth and other planets. Sound travels from a ...

Gamma brain waves are rhythmic electric processes in nerve cells called neurons. Nerve activity in the brain allows for communication throughout the brain to carry out functions such as memory, ...

Introduction You may have heard that light consists of particles called photons. How could something as simple as light be made of particles? Physicists describe light as both a particle and a wave.

Heat waves, also known as excessive or extreme heat events, are abnormally hot stretches of weather that usually last for two or more days. Wondering how hot heat-wave hot is? The answer varies from ...