Bill shows the world's smallest atomic clock and then describes how the first one made in the 1950s worked. He describes in detail the use of cesium vapor to create a feedback or control loop to control a quartz oscillator. He highlights the importance of atomic team by describing briefly how a GPS receiver uses four satellites to find its position. You can learn more about atomic clocks and the GPS system in the EngineerGuy team's new book Eight Amazing Engineering Stories http://www.engineerguy.com/elements

Bill shows how the three key characteristics of laser light - single wavelength, narrow beam, and high intensity - are made. He explains the operation of a ruby laser - the first laser ever made - showing how electronic transitions create stimulated emission to give coherent light, and then how the ends of the ruby cavity create a narrow wavelength highly collimated beam. You can learn more about laser in the EngineerGuy team's new book Eight Amazing Engineering Stories

Bill describes how metals like aluminum and titanium are made resistant to corrosion by growing an oxide layer into the metals. These is the same process used on many Apple products. This video is based on a chapter in his book Eight Amazing Engineering Stories.

Bill takes apart a smartphone and explains how its accelerometer works. He also shares the essential idea underlying the MEMS production of these devices

Bill takes apart a digital camera and explains how its captures images using a CCD (charge coupled device). He also shares how a single CCD is used with a color filter array to create colored images. This video is based on a chapter from the EngineerGuy team's latest book Eight Amazing Engineering Stories (Learn more at http://www.engineerguy.com/elements)

Bill uses a laser pointer and a bucket of glycol to show how fiber optic cables works, and how engineers use them to transmit signals across the ocean.

Bill uses a pile of cell phones to illustrate the seven design criteria that shape a mobile device. He outlines the seven basic constrain

Bill tears down a hard drive to show how it stores data. He explains how smooth the disk surface must be for the device to work, and he outlines the mathematical technique used to increase data storage.

Bill tears down an LCD monitor to show how it works. He describes how liquid crystals are used, the structure of the glass panes, and the thin film transistor (TFTs) that allow for active matrix addressing.

Bill takes apart a smoke detector and shows how it uses a radioactive source to generate a tiny current which is disrupted when smoke flows through the sensor. He describes how a special transistor called a MOSFET can be used to detect the tiny current changes.