Echoes, Sonar and Radar

Echoes

Echoes are sounds that are reflected off a surface and heard again.
The ability to hear an echo depends on the time delay between the original sound and the reflected sound. If this time delay is less than 0.1 seconds, the human ear cannot distinguish the echo from the original sound.
Echoes can help determine the distance of an object. If the speed of sound and time for the echo to return are known, the distance can be calculated using the equation: distance = speed x time.

Sonar (Sound Navigation Ranging) is a technology that uses sound waves to map objects under water or to determine distances.
Sonar uses the principle of echo to detect objects underwater. A sonar system generates sound waves which travel through water, bounce off objects, and are then detected by the system.
Calculation of the distance between the sonar device and the object can be performed if the speed of sound in water and the time taken for the sound wave to travel there and back are known.
Sonar is valuable for marine navigation, communication, and equipment such as fish finders.

Radar (Radio Detection and Ranging) is a system that uses radio waves to determine the range, angle, or velocity of objects.
Similar to sonar, radar operates by emitting radio waves and detecting the ones which are reflected back.
Radar is used in many applications such as air-traffic control, weather forecasting, and detection of speeding vehicles.
Radio waves travel at the speed of light, enabling radar to detect objects at large distances.
Radar can function in a variety of conditions including darkness, heavy rain, or dense fog, making it powerful for navigational purposes.