Cleaning Mrs. McElligot’s Pool


Dan and his best friend, Steve, were trying to earn money to buy model rockets.

Their first effort at homemade model rockets had been to take a used CO2 gas cartridge and stuff it full of match heads and light it.  Steve also forced more match heads into the cartridge by jamming an ice pick into it every few minutes.  They got a lot of match heads into it that way.

They knew it was the sort of an activity their parents would not really appreciate.  In fact, they had a strong inkling that anybody else would probably stop them, so they had holed up in the family garage, and were performing this rocketry hobby with the doors closed, so nobody could see.

In the excitement of the moment, Dan was holding the cartridge when Steve lit it.

After the first few ricochets off the garage walls, both boys managed to hit the floor and cover themselves with a tarp and some old carpeting that was laying there.  Miraculously, neither boy was hurt during this episode, although Dan figured the CO2 cartridge traveled about 7 miles in the next 30 seconds, all of it inside the garage.

They had a hard time explaining to Dan’s dad why the garage walls all had a curious dimpled look to them, but, Dan said, at least they learned about bunkers, and decided to pursue store bought model rockets.

Which brought up the need for earning money.

Mrs. McElligot, down the road from Steve, had a yard, and a garden, and agreed to pay them for various odd jobs. She had a list.

Today they were cleaning her circular pool. It was 15 feet across and about 4 feet deep. It didn’t count for much on an hourly rate, but cleaning a pool on a hot summer day made up for much.

“Steve, no!” Dan shouted. “If we run around and around the same direction, the heavy stuff will get pushed to the center and then we can scoop most of the gunky stuff up with the skimmer.  After that, we’ll get out the brush and vacuum, and we won’t have to work as hard.”

Steve stopped trying to attack the floating sticks and leaves with the net, and started following Dan around as he ran and swam around and around the pool.  They took turns trying to catch each other, lunging across the center of the pool, and being carried by the whirling water around and around.

“Lets get out and watch,” said Dan.

“Watch what?” Steve yelled.

“The center stuff, its like the Sun! Here, let’s get out and we’ll see.”  Dan got out and started watching.

“Look, all this liquid is going round and round, like a big centrifuge. And the thick stuff is dropping out in the center.  That’s like in the Sun.  The Sun is a big ball of fluidy stuff, and the light stuff — hydrogen and helium, is all on the outside, and the thicker stuff — iron and such, is pulled to the center. In the Sun it’s pulled by gravity.  But when it is swirling, it doesn’t swirl completely regularly. There’s swirls that carry all the thick stuff out to the edge, and swirls that extend to the top of the pool and then down again, and sometimes the swirl flattens out on the bottom of the pool and spreads the thick stuff out.”

“Yeah, so?” Steve asked.

“Here, grab the skimmer and collect that big gob of stuff in the middle.”

As Steve was swishing the skimmer through the swirl of leaves and sticks in the middle of the pool, he collected more in one pass than he had in ten passes before, but sending the skimmer through the middle swirl disturbed the column of swirling debris and scattered it throughout the pool.  When Steve brought the skimmer back for another pass, he tried to wiggle the skimmer through the debris, back and forth to contain the swirl as it scattered in front of the skimmer.

Dan was pulling stuff out of the filter that hung on the wall of the pool, but watched the action in the center intently.

“We’ll have to do that to the Sun some day, too, you know.”

“What?” Steve asked. “What are we going to have to do to the Sun?”

The swirling pool kept bringing the pile of debris together, more or less, in the center of the pool, and Dan started hooking up the pool vacuum to suck up the debris that was settling to the floor.

“We are going to have to suck the heavy stuff out of the center of the Sun or it will go nova.”

“It’s going to have to be a pretty big vacuum to suck stuff out of the center of the Sun!” Steve said. “Just how do you plan on doing it?”

“I don’t know yet,” replied Dan. “I suspect it will have to be like a big orbiting hair net made of Bucky tubes that makes some kind of magnetic field and forces the iron and silicon out the other side of the Sun, but that’s just a guess. It would produce some momentum that would push the Sun in a different direction, too, so we could steer it into clouds of hydrogen and refuel the Sun at the same time.”

“Wouldn’t that leave the planets behind?” Steve asked.

“No, it wouldn’t happen that fast,” replied Dan, “and all the planets, except Pluto maybe, would just adjust their orbits and follow along.  In fact, I bet the way we find out if there are intelligent aliens is when we find other stars that have iron tails pushing out from one of their poles with no good physics explanation for it. But it would show that some intelligence had grown enough to take charge of their own Sun and was steering it, keeping it from going nova, and refueling it in the process. It wouldn’t be limited to the normal life cycle of a typical Sun any longer either, and the civilization could last as long as there were clouds of hydrogen in the sky to feed into the Sun.”

Steve looked at his friend. “You’re pretty deep.”

“Nah,” said Dan, “only about 3 feet deep at the moment.” and he dove in under Steve and pulled him under too.

Both boys lunged out of the pool moments later, laughing and splashing each other, and left Mrs. McElligot, who was inside in her kitchen watching, with a grin on her face.

“Boys.” She thought to herself. “Boys just being boys.”