Sample Lesson

Radar

Introduction

The word “radar” is an acronym derived from the words RAdio Detection And Ranging. It refers to the technique of using radio waves to detect the presence of objects in the atmosphere. Radar was designed shortly before World War II. Its primary purpose was to detect the presence of aircraft. Today, radar is used for a wide array of applications, but primarily to detect precipitation and other meteorological events.

​To better understand the history of radar and how it works, read this article by Explain That Stuff:   LINK

Definitions
  • Antennaa usually metallic device (such as a rod or wire) for radiating or receiving radio waves a TV antenna
  • Duplexer –  an electronic device that allows bi-directional (duplex) communication over a single path. In radar and radio communications systems, it isolates the receiver from the transmitter while permitting them to share a common antenna
  • Electromagnetic spectrumthe entire range of wavelengths or frequencies of electromagnetic radiation extending from gamma rays to the longest radio waves and including visible light. 
  • Magnetron – a vacuum tube in which the flow of electrons is controlled by an applied magnetic field to generate power at microwave frequencies
  • Receiver – a device or apparatus that receives electrical signals, waves, or the like
  • Transmitter – an electronic device which generates a radio frequency alternating current. When a connected antenna is excited by this alternating current, the antenna emits radio waves​​
Videos

Quiz

A button appears here linking the student to the five-question quiz for the lesson.  This would take them to a separate quiz page.  In this sample lesson, the actual quiz is shown below:

 

  1. Radar is an acronym for Radio and Receiving?
  • True
  • False

 

  1. Radar was developed _________________.
  • Before World War I
  • Immediately after World War I
  • Before World War II
  • After World War II

 

  1. A/An ___________ is an electronic device which generates a radio frequency alternating current.
  • Antenna
  • Duplexer
  • Receiver
  • Transmitter

 

  1. Which of the following is radar NOT used for presently?
  • weather
  • crowd control
  • military uses
  • flight control

 

  1. A detected signal by radar is usually weak and must be amplified.
  • True
  • False

 

A passing score of 80% (4 of 5 correct) permits the student to move on to the next lesson.  Otherwise, they can retake the quiz after reviewing the material.