# If I can’t have my flying car, can I please have my flying battery?

MIT Technology review has a fascinating writeup on efforts to build electric planes. In my view, these efforts are at the same time shooting too low (the result would be the equivalent of flying short buses, at most) and possibly doable (which is good).

Have you ever noticed how much electricity weighs? Here is an experiment you can do. Get two identical alkaline batteries (small ones, like AA size), one totally discharged and the other fully charged.

Now, hold one in each hand and see if you can tell which one is heavier. Is the charged up one heavier?

No, of course not. Electricity stored as potential energy in a battery actually weighs nothing. This is an interesting idea. Airplane fuel does weigh something, but electricity itself does not. If only we could create a battery that weights almost nothing to carry all that weight-free electricity!

OK, now, while you are still holding the batteries, try something else. Do this quickly, because you don’t want anyone asking you “why are you holding these batteries” right now, because you’d have to say, “I’m trying to see how much electricity weighs,” and that is kind of a stupid question.

Hold the batteries over a hard surface that you don’t mind dropping a battery on. Maybe ten inches to a foot above the surface. Hold them upright. Now, drop them on the surface and see how they act.

The “full” battery, the one with the charge, will normally bounce better than the “empty” one.

This proves that something interesting is going on inside the battery. What? I don’t know, but I suspect it is at least tangentially related to the science behind the aforementioned MIT Technology Review write up: Top battery scientists have a plan to electrify flight and slash airline emissions. Go read it, it is very interesting.

After reading this, I had this thought: Have a relatively small battery i an aircraft that does not use the same exact technology as the long distance battery, and is good at ONLY rapid output of a lot of power, and is replaced and recycled after every flight. Ideally, the plane would actually drop the battery once it is done using it. Neighbors of airports may object.

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## 3 thoughts on “If I can’t have my flying car, can I please have my flying battery?”

1. Ketil Tveiten says:

You have the battery bounce wrong: the full battery will thud to the table without much bounce, while the empty one will have a decent bounce.

2. Douglas C Alder says:

” Have a relatively small battery i an aircraft that does not use the same exact technology as the long distance battery, and is good at ONLY rapid output of a lot of power,”

You appear to be describing a capacitor not a battery – the one stores potential energy as an electric field the other as chemical energy.

3. Douglas C Alder says:

Mia culpa – just read the article – ignore previous post ðŸ™‚