Jacob Bickell asked his mother for some change. They were shopping at the South County Center on Sunday and he saw something that amused him.

He wanted to roll some coins into a spiral wishing well, one of those plastic vortex things that, at first glance, looks like a hot tub.

He took a quarter and placed it into the launching slot. Jacob, 11, let go and the coin began to roll in wide circles down the vortex. As it rolled farther down the steep side, the circles grew shorter and shorter until the coin was a blur, then plopped into a hole at the bottom.

Jacob and his mother, Deanna Bickell, both smiled at the mini-physics lesson. Centrifugal force kept the coin on its edge during the whole trip.

For Jacob, physics wasn't the reason why he rolled the coins.

"It's a lot of fun to watch," he said.

Deanna also enjoyed it.

"I wish I had one at home," the Affton resident said.

These spiral wishing wells are common sights at shopping malls. The coins go round and round, always staying on their edges. The money then goes to various charities.

In a world where so much entertainment for kids is tied into video games or the home computer, there is something refreshing about the simplicity of a spiral wishing well. Just launch the coin and it takes care of itself.

One mother was dragged to the wishing well by her three young children. They all begged for coins. They each dropped several and watched them go round and round.

Finally, the mother announced she had run out of change. That, or patience.

Several parents with small kids walked past it. The children took longing looks, but mom and dad were at the mall for shopping.

One father seemed to be more enthusiastic, asking his teenage daughter if she'd like to try it. The girl gave her father a shrug and shook her head "no." He looked disappointed.

Small printed signs on the wishing well suggested people try a science experiment. Drop four different coins to see if their different weights would make them run faster or slow than the others.

After a while, I decided to try it. I chose a penny and a quarter. Armed with my cell phone stopwatch, I launched the penny.

While I was standing timing the coin, a couple of people stopped and looked.

Round and round and — plop! — the penny made the journey in 30.19 seconds. I told them the time. They moved on.

Then, the quarter. I launched it. Unfortunately, I hit the wrong key on my cell phone and stopped the time. I dug out another quarter and tried to again.

The 25-cent piece finished at 25.1 seconds.

The results demonstrated that the bigger coin moved faster. This was my first science experiment in about 40 years. All for 51 cents.

Nobody else rolled a coin during the rest of my time. People were busy, carrying packages and leaving the mall.

That, or they just didn't have any change.