Weirdness of Physics


I got a battery-operated mower for this season: I needed a new mower, wanted to try out the technology, and given the hour at which I mow on a Texas Sunday—before it gets too hot—I wanted something quieter than a traditional gasoline-powered machine.  However, unlike modern gasoline-powered mowers, this one is human propelled.

The mower's design facilitates dismounting the battery for recharging between mowings; for me, this amounts to a walk of some 30 feet from my wife's garden shed where I store the mower to the garage, where I recharge the battery.

That's a long introduction to get to the weird physics matter.  I've noticed, now, some 3+ months into the mowing season, that the battery is quite light when it's fully charged and I'm carrying it out to the mower.  However, after it's given up all those electrons to the mowing operation, the battery has gotten quite heavy for the carry back to be recharged.

Hmm….

Eric Hines

11 comments:

Grim said...

I used to use one of those old-fashioned ones, somewhat like this. It worked great (and was almost perfectly quiet). I don't know how large a section of lawn you're mowing, though: this was back when we lived in the town of Warrenton, VA, and had a lawn that was more decorative than sprawling.

E Hines said...

I did one of those when I was a boy in Iowa and upstate Illinois. When I got to Plano, though, I was older, lazier, and wanted taller grass. I tried one of those my first year here, and decided a new-fangled thingie with a separate power source for spinning the cutters would be better.

Eric Hines

bthun said...

Battery weight fluctuates noticeably with the state of the charge? Hmmm... Could it be that your battery's cells are immersed in light water? Does the battery glow in the dark? =;^}

"I used to use one of those old-fashioned ones, somewhat like this."

Hey! Is that a reel mower or a Sears mower?

Yep, I suspect most of us, of a certain age, grew up with a reel mower. Filing/sharpening the blades was a fun exercise.

Another tool I fondly recall using early in life, one that many younger folks might not be familiar with, is this type of PB&J propelled brush/grass cutter. A real handy tool for a kid wanting to cut trail through tall grass.

Grim said...

Yep, I've got one of those in the basement. I use it sometimes when I don't feel like mixing up fresh fuel-oil. It's kind of fun, although -- unlike the reel mower -- it produces a visibly inferior cut if you're trying to trim for appearance.

If you're just cleaning out a ditch, though (and that is often the case around here), they work great. If some part breaks, too, it's usually repairable with an old nail or some fence wire.

bthun said...

In my rush to get back on the honey-do list I neglected to ask you Mr. Hines if you could quantify that before/after battery weight fluctuation with a scale?


// the hun's not going to admit that after he engages in manual labor, for more than a little while, objects do seem to weigh more than they used to... Especially since he's not yet determined the cause... *cough* time marches on *cough* //

E Hines said...

...quantify that before/after battery weight fluctuation with a scale?

On the Sineh Scale of Not Much-to-A Whole Lot, the weight gain from the electron loss seems linearly related to ambient temperature (slightly), but it generally works out to the region of Quite A Bit on the graduated marker.

Does the battery glow in the dark?

No, but it has a charging light that does....

Eric Hines

bthun said...

" If some part breaks, too, it's usually repairable with an old nail or some fence wire. "

Right enough for most of the old, tried and true tools of yesteryear.

I think I've mentioned dad's axe here once or twice before. The one on which my bro replaced the head and a decade or two later, when it came into my possession, I replaced the handle...

Yup , I surely cherish 'dad's axe. =8^}

Grim said...

That raises kind of what we'd call an ontological question, bthun. If he replaced the head and you replaced the handle, to what degree is it still the same axe?

I've got an axe that's been through a couple of handles myself. I had a sledgehammer that finally broke at the hilt, and when I took it in to get a new handle they reminded me it was stamped "Craftsman" in the steel, and gave me a whole new one for free.

E Hines said...

...gave me a whole new one for free.

So, your sledge lives on, reincarnated.

As does bthun's Dad's axe, reincarnated by parts.

Eric Hines

Grim said...

Like I said, ontology. Longevity. Incept dates.

bthun said...

"Like I said, ontology. Longevity. Incept dates."

Which makes me think of how much of our history is lost or diddled beyond recognition in subsequent generations, so I'll follow that link with another excerpt from the same movie: "All those moments will" [inevitably] "be lost".

Or I may just be in a pessimistic mood from being woe-out due to the around the clock food prep and canning of the last several days.