3 June, 2000

The Ping Puzzle

June 3, Saturday

Ping, ping, ping.

“Hey, Barry. I think we’re getting pretty close to the bottom,” said John Freitag. John and Barry are monitoring some of new equipment on the Healy. "Call up to the Aft Science Conning Station and find out how much wire they've payed out."

John and Barry thought they knew what the answer would be. But when the call came from the winch operator in the Conning Station, it wasn't what they were expecting. From the maps they were using, John and Barry knew that the ocean was about 4,150 meters deep in the spot where they had lowered the pinger down. (The pinger is an instrument that tells scientists how far away it is from the bottom of the ocean.) They calculated that it was now about 150 meters off of the bottom. That would mean that they had already lowered the pinger 4,000 meters into the ocean.

The winch operator, who was lowering the pinger on the cable, was also keeping track of how much cable he had used. According to his calculations and meters, he had payed out (let out) only about 3,000 meters of cable.

Uh, oh! The scientists on board the Healy now had an interesting puzzle to solve.

Why would there be such a big difference between what the scientists were seeing and what the winch operator was seeing? Time for some problem solving now.

Clue 1: There are four magnets on the wheel that the cable is wound around. Clue 2: Every time the wheel turns, a sensor records that the four magnets have gone around.

It took a lot of discussion and problem-solving, but the scientists and marine science technicians finally figured it out!

One of the magnets had fallen off the wheel. Instead of four magnets, there were now only three. You already know that 1 out of 4 is the same as 25%. That means that the winch operator's calculations were off by 25%, which in this case was 1,000 meters. You don't want to make a mistake like that if the equipment you are lowering down in the water is worth thousands of dollars! If it crashes on the bottom of the ocean floor, it could be ruined. That's why the scientists like to use the pinger as a precaution.

How does this pinger work anyhow? To find out that answer to that, click on Susan’s page!

Susan’s Entry Today.

DAILY DATA LOG (6/03/00):

Air Temperature: 0 degrees C / 32 degrees F

Clear skies, sunny

Latitude 51N

Longitude 52W

John and Barry monitoring data from new equipment.

The cable is kept below the deck.

This is the aft science conning station. The winches are controlled from here.