PBS
The Leap Second Explained
Everyone's heard of leap years ... but what about leap seconds? Young scientists get acquainted with one of humankind's most awkward standard measurements with a short video from a PBS playlist covering space and time...
CK-12 Foundation
Ck 12: Elem Math: Matching the Analog and Digital Clocks
[Free Registration/Login may be required to access all resource tools.] In this learning module, students are asked to match times on analog and digital clocks to the hour and half-hour. Includes video demonstrating a sample problem...
Khan Academy
Khan Academy: Electrical Engineering: Signals and Systems
Signals and Systems covers analog and digital signal processing, ideas at the heart of modern communication and measurement. We present the basic concepts for continuous-time and discrete-time signals in the time and frequency domains....