Long-held theories about how materials melt, freeze and evaporate
 may need to be tweaked thanks to some breakthrough research.
A UCLA-led team of scientists have captured the 4D movement of
atoms through time and 3D space as they changed states, reportedly
 for the first time. The results were surprising and contradicted
classical theories about "nucleation," when atoms start to
 change from one form to another. The research may prove
valuable for the creation and study of new materials, chemicals and biological processes. Building on past research, the team used Berkeley Lab's
 latest 3D electron microscope to examine an iron-platinum
alloy sliced into nanoparticles 1/10,000th the width of a human hair.
Those were heated to 968 degrees Fahrenheit, causing them to pass
from one solid state to another. 3D images were grabbed at
 9, 16 and 26 minutes after heating while the sample was
rotated in the microscope.Using special algorithms, the team
tracked the same 33 nuclei, just 13 atoms wide, located in a
single nanoparticle. "People think it's difficult to find a needle in
 a haystack," said UCLA physics and astonomy professor Jianwei
"John" Miao in a statement. "How difficult would it be to find the
same atom in more than a trillion atoms at three different times?
"As expected, the alloy changed from a slightly random state to
one where the platinum and iron atoms were more neatly aligned.
 However, the scientists noted that the nuclei formed irregular
 shapes rather than perfectly round ones predicted by
long-existing theories.
Furthermore, rather than having sharp borders as expected,
 the arrangement of atoms was more jumbled near the surface.
While those results might not sound exciting, it's the first that
 nucleation has been seen in action. "Nucleation is basically
an unsolved problem in many fields," said co-author Peter Ercius.
"Once you can image something, you can start to think about how
 to control it." That could lead to better, stronger materials and a
 deeper understanding of crucial chemical and biological reactions.