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Hockey players move faster than players in any other team sport.
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To be in the NHL you need to be, among other things, an
exceptional skater. The players and coaches seem to agree that to be an
effective skater, you need a combination of good technique and physical
strength (although individual responses differed as far as which was the
more important quality). The scientists in this section help break down
the mechanics and physics of skating. Our exploration starts with the interaction
between the blade and ice surface.
In this section there are RealAudio and video clips
from chemist Gabor Somorjai of Lawrence Berkeley National Laboratory, Sharks'
strength and conditioning coach Steve Millard, and Exploratorium scientist
Thomas Humphrey.
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Slippery when not wet?
The nature of ice was examined in "The Ice" section--including
the latest findings by chemist Gabor Somorjai. This new information about
ice changes the way we look at skating. For a number of years before Somorjai's
research, there was a debate as to whether pressure or friction created
the water lubricant that was believed to be required for skating. Most scientists
seemed to think that it was pressure. According to Somorjai's findings this
is not the case. So what do you skate on? Well, actually you skate on vibrating
molecules.
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Professor Somorjai discusses how his discoveries differ
from the long-held theories about how people skate.
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Professor Somorjai and his team used new methods developed
in the last 10 or 15 years to examine the surface structure and composition
of the atoms and molecules that make up the ice. These techniques were developed
for high-tech applications--like studying the surface of materials that
can be used for magnetic disk drives, for example. Somorjai used these same
methods to examine ice. What he found was rather surprising. Somorjai told
us, "the structure we determined was an almost impossible structure,
indicating that every second water molecule on the surface was missing.
Since that was not possible, we decided to go back and understand why [this
was the case]." After further study, Somorjai's team found that the
"missing" water [or ice] molecule was indeed there-- but it was
vibrating so rapidly that it was invisible to the technique they were using.
Once Somorjai and his team found this out, they could change the conditions
to further study these molecules.
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Up and down
After further study, Somorjai found that these molecules
behave like a liquid, but they only move up and down; they do not move from
side to side on the surface of the ice. This is an important distinction.
If the atoms moved side to side, the "liquid-like" layer would
literally become liquid (which is what happens when the temperature rises
above 32 degrees Fahrenheit). This "liquid-like" layer is thought
to be what makes the ice slippery.
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Professor Somorjai uses this vacuum chamber to study the surface of ice
and other materials. The vacuum chamber provides a controlled environment
for his research.
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Click the "forward"
button below to continue.
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Exploratorium
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