It seems that when children are drowning, they don’t thrash about, but instead they first go silent.
Today’s invention is a life-saving technology which takes advantage of this scary information.
Each child entering a body of water would put on a waterproof collar with a throatmike and a small transmitter embedded.
Each child’s signal would be monitored by a system on dry land.
In the event that a given youngster was substantially less noisy than its own average for say 20 seconds, a light on the collar would illuminate, alerting adults in the vicinity.