NOVA: What the Physics?! Collection
In this collection, you’ll find original short-form videos from What the Physics?!, a YouTube series hosted and produced by Dr. Greg Kestin. Each episode addresses a surprising or interesting phenomenon related to physics. Explore questions related to topics such as the speed of light, how cell phones work, and quantum mechanics.
Learn how a small amount of oil can have a calming impact on a large body of water, in this episode of What the Physics?! from NOVA. When a tablespoon of olive oil is poured into a lake, the oil spreads out to cover about half an acre and calms the waves. As the oil molecules are attracted to the water molecules, a single-molecule-thick layer of oil is created. This thin layer of oil acts like a tangled carpet that the wind drags across the water. Because the wind cannot act directly on the water to create waves, the surface of the lake stays relatively calm. This resource is part of the NOVA: What the Physics?! Collection.
NOTE: Do not try this experiment in a public body of water.
Learn how gravity changes the color of light, in this episode of What the Physics?! from NOVA. Einstein predicted that light moving in a gravitational field would change color as it travels—it would undergo gravitational redshift or blueshift. In 1959, researchers Robert Pound and Glen A. Rebka Jr. tested Einstein’s hypothesis with thin sheets of iron-57, which only emits and absorbs a particular frequency of light. They punched holes through all the floors of a building to create a five-story path for light to travel downward from the attic to the sub-basement. Using a speaker to create a Doppler redshift to counteract the gravitational blueshift, they provided evidence that gravity does change the color of light. This resource is part of the NOVA: What the Physics?! Collection.
Explore three things that seem to be faster than the speed of light, in this episode of What the Physics?! from NOVA. According to Einstein, no matter or information can travel faster than the speed of light. However, at first glance, distant galaxies, clever paper slicing, and quantum-entangled particles all seem to exceed the speed of light. Do these examples disprove the fundamental notion of a cosmic speed limit? This resource is part of the NOVA: What the Physics?! Collection.
Learn how text messages travel from cell phone to cell phone, in this episode of What the Physics?! from NOVA. Cell phones use antennae to transmit and receive radio waves that carry binary information. Every cell tower presides over an area of land, where it receives and transmits radio waves. When a text message is written, it is transmitted as binary code using a particular frequency of radio waves specific to that user. The signal is received by a nearby cell tower, which then directs the information to be transmitted by another tower near the intended recipient. Cell towers are connected by a network of computers that constantly monitor the locations of cell phones so that each phone can communicate with the tower closest to it. This resource is part of the NOVA: What the Physics?! Collection.