Sound - To ascertain the depth of water with a sounding line or other device.
Sounding rockets are used to lift scientific instruments above the stratosphere.
Unmanned balloons with scientific payloads generally reach an altitude between 30 and 50 kilometers. Satellites orbit above 200 kilometers. The only practical way to make scientific measurements at altitudes between these two extremes is to use a sounding rocket. A sounding rocket is any off-the-shelf solid-fuel rocket used to send a payload of sensors along a parabolic trajectory. | 
