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| There are a lot of strange ideas about snowflakes, water, and ice out there. Here are my opinions on a few.... |
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 The Hidden Messages in Water
Masaru
Emoto published several books claiming that ice crystals grow
differently when water is first exposed to different thoughts and
feelings. For example, he may start by playing assorted varieties
of music -- jazz, classical, rock-and-roll, etc. -- to different
containers of water. The music is then turned off and the
"treated" water is used to grow snow crystals. He claims that the
different musical treatments yield different types of snow crystals,
and shows us pictures of the results to prove his case.
If you
think it defies common sense that water does this, you are right.
In fact water does not respond to thoughts and feelings - it's just
water. How then does one explain Mr. Emoto's experiments?
My best guess is that Mr. Emoto grows hundreds of crystals and then
selects different shapes to demonstrate whatever point he wishes to
make. For example, when the water was exposed to classical music
he picks out some beautiful crystals to show us. For
rock-and-roll, he selects some ugly crystals and shows us those.
He then concludes that classical music makes beautiful crystals while
rock-and-roll makes ugly ones. What he does not show us is that
both musical treatments made the same numbers of beautiful and ugly
crystals. The "treatments" actually had no effect.
Do I
know Mr. Emoto does this? No, which is why I called it a
guess. Mr. Emoto has never published his work in a reputable
scientific forum, where it would be scrutinized. He only presents
it in self-published books, where he is free to say whatever he
wants. Basic physics says the work cannot be correct, and Mr.
Emoto has not convinced the scientific community that his experiments
have any merit whatsoever.
Have I tried to reproduce Mr. Emoto's
experiments? No, and I don't intend to. While I try to keep
an open mind to new ideas, this one is just too outrageous. I
only have limited time and resources, so I study ideas that I think are
more likely to be fruitful. As we liked to say back on the farm
in North Dakota -- it's good to have an open mind, but not so open that
your brains fall out! |
|  Repeating Snowflakes
Is
it true that when a snowflake melts and refreezes, it freezes into the
same shape it had before? Nope; not even close. That's just
a tall tale that's been circulating around for many years. Here
again, water does not have any memory. It's just water.
I
think I can guess the origin of this story. If you make a video of
a melting snowflake and play the video backwards, it look like the
snowflake just pops out of a drop of water, as if it "knew" what final
shape it would take.
I grow lots of desiger snowflakes in the lab, and I make videos of them growing (not the same as melting in reverse!). The crystals always follow what one expects from the science of ice crystal growth. |
|   Snowflake Perfection?
Are
there not some special forces at work that ensure that snowflakes form
so symmetrically? People are sometimes convinced that the simple
explanation of snowflake symmetry cannot be correct, because snow
crystals are too perfect in form. These folks argue that the
simple explanation would likely yield less ideal shapes, less perfect
six-fold symmetry. Therefore they suspect something else is
happening -- perhaps some acoustical or quantum mechanical oscillations
are enforcing symmetrical growth.
The flaw in this reasoning is
the statement that snow crystals are all extremely symmetrical.
You can disprove this for yourself if you simply go outside and take a
close look at some falling snow. You will soon realize that the
beautifully symmetrical specimens are hard to find! The rather
unattractive irregular crystals are by far the most common variety (see
the Guide to Snowflakes
under the heading of Irregular Crystals for some pictures). Even
on the best of days, I search for hours to find just a few beautifully
symmetrical specimens. I typically glance over
thousands of crystals on my collection board before selecting one to
photograph, and the pictures you see in the Galleries are some of the
best among over 10,000 pictures I've taken.
Alas, the vast
majority of snow crystals are not even close to perfectly
symmetrical. The simple mechanism does indeed produce much
imperfect symmetry, as you would expect. I always select their
most symmetrical crystals to display ... after all, not many people are
interested in looking at the irregular ones! |
|  The Mpemba Effect
The
Mpemba effect, named after Erasto Mpemba, suggests that warmer water
freezes more quickly than colder water. Alas, there is no solid
evidence supporting this statement.
The Mpemba effect is a
remarkably widely held belief, even among scientists. Many physical
theories have been put forward to explain the Mpemba effect, but that
still doesn't make it true. I spent some time looking carefully at
the experimental evidence for
the Mpemba effect, and it just wasn't there. The more carefully the
experiment was done, the more it looked like there was no Mpemba
effect, not really.
But you have to look carefully at the
experiments. Water will supercool before it freezes, and it takes some
nucleation event to start the water freezing. Nucleation is a very
tricky business, being extremely sensitive to dirt in the water,
scratches on the walls of the container, vibrations, etc. If you put
several seemingly identical containers in a freezer at the same time,
the freezing times will vary all over the place. If you start with warm
and cold water, sometimes the warm water will freeze before the cold,
but sometimes the opposite will happen. The closer you look for the
Mpemba effect, the more you find that it isn't there. | | |
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