Modifications

RossG

Esteemed Pedelecer
Feb 12, 2019
1,476
1,448
You can of course see the clouds and create rain, I think they use iodine crystals.
 

vfr400

Esteemed Pedelecer
Jun 12, 2011
6,900
2,661
Basildon
Yes, it's rather badly worded isn't it. The effect has been widely observed since the days Aristotle, so there are clearly many sets of initial parameters where the effect is observed, many "thousands" even.



So their results invalidate the research of many others eh? That's not quite how scientific method works, try Googling "Mpemba effect" there are lots of write-ups about it.
No, it doesn't invalidate any research. The effect is real, but it seems that nobody can agree what it is and how it happens. The problem is that it's not repeatable because the initial conditions that create it are difficult to pin down. You can't say that it's a rule that hot water freezes before cold water. The likelihood is that it won't, but in some circumstances, it apparently can, though they don't seem to have pinned down exactly what that means. The latest research showed that the hot water doesn't get to zero first. Water has anomalous expansion so that it has maximum density at 4 deg C, which makes it freeze from the surface. That means that you can have one beaker with ice on the surface (0 deg at surface and 4 deg underneath before one that's at a lower temperature (1 deg homogeneous) if the one with ice in had some conditions that would cause the temperature gradient from top to bottom to be maintained.
 

RossG

Esteemed Pedelecer
Feb 12, 2019
1,476
1,448
Let's not forget water becomes less dense as it freezes not more. I have a feeling this effect may be linked to Brownian motion but so far I can't find a link which refers to that, so I'm probably barking up the wrong tree !
BTW any theory's on my observation of water droplets travelling up a wire ?
 

Woosh

Trade Member
May 19, 2012
14,978
12,250
Southend on Sea
wooshbikes.co.uk
BTW any theory's on my observation of water droplets travelling up a wire ?
it's called the capillary effect or adhesion. The wall of the wires are more polar than water, so water gets more attracted by the wires than by its neighbouring water molecules (attracted by neighbours = cohesion).
 

RossG

Esteemed Pedelecer
Feb 12, 2019
1,476
1,448
it's called the capillary effect or adhesion. The wall of the wires are more polar than water, so water gets more attracted by the wires than by its neighbouring water molecules (attracted by neighbours = cohesion).
That's what you would imagine it would be but there are problems with that from what I can see.
As the water droplets moved up the wire they would merge with others, increase in size and eventually rush down the wire or just drip off.
I have a feeling this phenomena may have something to do with static charge on the wires...more research needed.

@ slarti.
Yes the water seed mod definitely works. If you're out on your bike and water droplets start to fall from the sky your speed increases by about 20% sometimes more. I would advise anyone who wants a quick speed boost to always carry a packet of Iodine crystals in their back pack.
 

therealvicz

Finding my (electric) wheels
Jan 26, 2019
7
0
Telford
“‘A pint of water weighs a pound and a quarter, a gallon weighs 10 pounds” pounded into me in primary school many years ago. It’s also why there are twenty fluid ounces in a pint. All UK measurements of course, USA gallons are different. 1 litre of water weighs exactly 1kg. Rounding errors in your conversion left you .0028lb out, not too shabby...