The Beep From the Old Water Tower
Jamal was testing the handheld radio that he had received for his birthday when he picked up an unfamiliar sound. It was a steady beep that repeated once every ten seconds, and it never varied. He wrote the time in his logbook, turned the dial away, and found the signal again right where he had left it.
"It's not a person," he told his friend Sol. "It's a machine, and it must be somewhere nearby."
The signal grew louder when Jamal pointed the antenna in one direction and softer when he turned it in another. The boys therefore walked down Mill Road, pausing at each corner to listen and to note which direction made the beep strongest. Their route gradually bent toward the edge of town, where the old water tower rose behind a tall fence.
They did not attempt to climb the fence, because Sol pointed out the "No Entry" sign. Instead, Jamal stood at the gate and held the radio high above his head. The signal was at its loudest, so it had to be coming from the tower itself.
The two of them walked to the town office and described what they had found. A clerk made a phone call and then thanked them warmly. "That is a small weather sensor," she explained. "A repair crew hung it up last month, and it sends out a beep to let them know that the battery is still working."
On the way home, Sol grinned. "You solved a mystery with a birthday present."