

Why a Dead Alkaline Battery Bounces [video] - Walkman
https://www.youtube.com/watch?v=qrGV7zKEdtU

======
haar
I think one of the bits I liked most was "Romeo (Retired Old Men Eating Out)
Club" \- looking at its website it seems like quite a large thing over there.
I know that my Grandma goes to something similar (restricted to just tea and
bingo), but it makes me wonder if a similar organisation exists in the UK; a
lot of the older folk I know just aren't very social any more, simply due to
the fact that their social groups have died off or are spread out and have
restricted travel options. Social interaction seems such a huge part of our
existence to be missing for any individual (unless that's what they want of
course).

Again, anecdotally; I've found amongst the older folks that those engaged in
discussion and interaction keep their wits about them longer/easier than those
bound by isolation.

Anyway, enough babbling on - time to go do some research.

~~~
mhandley
One excellent organization is U3A
[http://www.u3a.org.uk/](http://www.u3a.org.uk/) My father runs one of their
groups that specializes in studying geology, and they regularly have a hundred
people turn up to the seminars they run. Science and social go well together
when you've lots of free time.

~~~
warbastard
My father also runs one of these to help people learn Photoshop (mainly for
editing family photos). It's surprising the topics that can be learned though
these groups

------
mixedbit
They could go further with the experiment to check if a material of which the
battery content is composed matters or if the stiffness of the content is the
only important factor.

They could for example check how bounciness changes when a battery is filled
with a gel-like substance which could then be frozen.

------
tke248
Here is the transcript if you don't like watching the video
[http://bit.ly/1uD31Uz](http://bit.ly/1uD31Uz)

------
macromaniac
It's interesting to me that using the height of the bounce against the ground
for estimating the spring constant is worse than using the height of the
bounce against the battery.

~~~
jacquesm
I don't really agree with that part of the test setup. The mass and
springiness of the battery versus the slug dropped mask the fact that this is
a _double_ spring setup, there is also still the bottom of the battery
contacting the base it all sits on so you can expect some of the bounce to be
transferred to the battery which would not jump a whole lot. So at a minimum
there would have to be a hard connection (clamped or glued in place or
something like that) between the base and the battery to compensate for that.

------
dblacc
What would the inside of a recharged battery look like I wonder.

~~~
simias
It's not the same technology and I wouldn't recommend tearing a lithium
battery apart to look inside. Actually, I wouldn't recommend tearing apart any
kind of batteries, lots of nasty stuff inside.

You can find plenty of videos on youtube showing you the process, for
instance:
[https://www.youtube.com/watch?v=BliWUHSOalU](https://www.youtube.com/watch?v=BliWUHSOalU)

~~~
junto
After watching that it made me think that lithium batteries could be turned
into a weapon on a plane by terrorists.

Assuming that they are that easy to accidentally short them out.

Should they not be a banned from being taken in the cabin?

~~~
iamds
It's probably not banned because someone who could take over a plane with a
lithium battery could take over a plane without a lithium battery.

~~~
leephillips
But someone who could take over a plane with a nail clipper could probably
manage without it, too.

~~~
kd0amg
And the TSA allows nail clippers in the cabin.

------
JosephRedfern
The method has even been patented!
[http://www.google.co.uk/patents/US5567541](http://www.google.co.uk/patents/US5567541)

~~~
mdda
The patent was drafted very generally, but seems to focus on the volume
(rather than elasticity) of the internal components. OTOH, it would be great
if it were even more generally drafted, since its priority date is in 1995.
1995+17 = 2012, so the world is now wide open for innovation in this area,
unimpeded by patents (IANAL).

------
keeperofdakeys
Probably not the best idea to open a battery without gloves and a mask (though
lithium batteries are worse in terms of gases).

Still very interesting to see the electrolyte though.

~~~
jacquesm
The quantity and variety of things that I've opened up during my lifetime
without 'gloves and a mask' would probably scare you very much. The worst
mistake I made to date is grinding off the top of a BLY90 as a kid before I
knew what a MSDS is. So far so good, I think these folks will be fine as long
as they wash their hands afterwards before eating, cleaning up after you've
dropped a fluorescent tube is probably a lot more dangerous than this.

Don't go and turn anything into a fine powder!

Probably the most risky thing they did here was cutting up the batteries with
a hacksaw which will create a bit of sawdust composed of metal and some
electrolyte. But that's pretty easy to get rid of and won't become airborne.
Using a grinder for the same job would be much more dangerous.

~~~
akavel
As to what people would play with without "gloves and a mask":

[http://en.wikipedia.org/wiki/Demon_core](http://en.wikipedia.org/wiki/Demon_core)

 _" After Slotin's accident, hands-on criticality experiments were stopped,
and remote-control machines were designed by Schreiber, one of the survivors,
to perform such experiments with all personnel at a quarter mile distance."_
Note: _" After"..._ so what was the situation before?...

~~~
cjslep
They would raise and lower the top half of the core with their bare hands, a
screwdriver, and lots of shims. Literally hands-on criticality experiments.

------
rtb
For some reason, it upsets me that he refers to spent / empty / used batteries
as "bad", as if they were faulty.

~~~
jasallen
He managed avoid the "flat" vs. "dead" controversy by making up a new
convention altogether.

~~~
bitJericho
I think "consumed" would be most appropriate.

~~~
fnordfnordfnord
I'd say "depleted" but we're all missing the point.

------
dang
Url changed from [http://lifehacker.com/test-if-your-batteries-are-dead-by-
dro...](http://lifehacker.com/test-if-your-batteries-are-dead-by-dropping-
them-on-a-h-1630525062), which points to this.

~~~
tzs
Due to a Feedly bug (I think), this actually makes it much harder for Feedly
users to comment. When an HN story links directly to YouTube, Feedly omits the
link to the comments that is normally present in its display of HN RSS.

I think this is a Feedly problem, not an HN RSS problem, because it works fine
in Digg Reader.

I'm curious if others have noticed this. I believe when someone posted a poll
question here asking what RSS readers people switched to after Google Reader
went away, Feedly was one of the most popular.

------
lowglow
Electrons change things, yo™ :)

~~~
tbingmann
It has electrolytes!

~~~
peterclary
It's what plants crave.

