» » » Geek Trivia: What Were Planes Detected With Before The Invention Of Radar?

Geek Trivia: What Were Planes Detected With Before The Invention Of Radar?

,

What Were Planes Detected With Before The Invention Of Radar?
  1. Acoustic Mirrors
  2. Telescopes
  3. Pigeons
  4. Ultrasound

Think you know the answer?



from How-To Geek https://www.howtogeek.com/trivia/what-were-planes-detected-with-before-the-invention-of-radar/
via IFTTT
loading...

Related Posts


Subscribe to: Post Comments (Atom)