Which device is used to determine the distance of an object under water by recording echoes of sound waves?

The device used to determine the distance of an object underwater by recording echoes of sound waves is sonar. Sonar operates by emitting sound pulses, which then travel through the water and bounce off underwater objects. When these sound waves return to the source, the time it takes for the echoes to return is measured. By using the speed of sound in water, the device can calculate the distance to the object based on this time delay.

This method is particularly effective in underwater environments where visual methods are often ineffective due to factors such as light absorption and turbidity. Sonar is widely utilized in various applications, including submarine navigation, fish finding, and underwater mapping, making it an essential tool in marine exploration and research.

In contrast, radar is more suited for detecting objects above water, such as aircraft or ships, and does not work effectively underwater. A gyrocompass is used for navigation based on the Earth's rotation and is not involved in measuring distances underwater. An altimeter measures altitude above a specific level, typically above sea level, and is unrelated to underwater measurements.