There are many different sensors that can be used to detect motion in a given environment. Passive InfraRed (PIR) sensors are the most used today, as they work by detecting moving heat signatures.

Scientists have detected the Doppler effect — a quirk of physics that makes an ambulance's siren change pitch as it drives by — on the scale of a single molecule. The Doppler effecthas been understood ...

CORVALLIS, Ore. – Whether they know it or not, anyone who's ever gotten a speeding ticket after zooming by a radar gun has experienced the Doppler effect – a measurable shift in the frequency of ...

We know the Doppler Effect as the reason why horns and sirens drop in tone as they rush by us. But the Doppler Effect works on objects that are twisting around, too. We’ll tell you how the Doppler ...

Sitting on the beach at Gecko Island one afternoon, A man finds himself beneath the flight path of the airplanes leaving East Blue Airport. a) What frequency will the man hear as a jet, whose engines ...

Krzysztof Bolejko receives funding from The University of Sydney. He is affiliated with Sydney Institute for Astronomy. There are so many galaxies in the universe that if you point a telescope in any ...

Studies of photoemission processes induced by hard X-rays including production of energetic electrons have become feasible due to recent substantial improvement of instrumentation. Novel dynamical ...

The Doppler effect, discovered in 1842 by Christian Doppler, is familiar to most of us; stationary observers of waves such as sound waves will see wavelengths that depend on the relative motion ...