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LIAM McHUGH: From Olympic champion Evan Lysacek…
EVAN LYSACEK: Imagine what it's like to hurl your body in the
air and rotate four times.
McHUGH: ...to Olympic hopeful Ashley Wagner...
ASHLEY WAGNER: This is what I've been working for
my entire career.
McHUGH: ...figure skaters push themselves through incredible
jumps, spins, lifts, and throws - on ice - and make it look
elegant and effortless.
GRACIE GOLD: From your starting position to your very last
movement, and even the way you get off the ice,
every detail counts.
McHUGH: Making the difficult elements look effortless takes
exceptional artistry, athleticism and a solid
understanding of some basic principles of physics.
BRAD ORR: There is no better example of physics than on an
ice skating rink. It's a wonderful place to see science.
McHUGH: Brad Orr is the head of the Physics Department at the
University of Michigan and has been funded by the National
Science Foundation. Orr explains that good balance, or stability,
is basic to everything a skater does - and that begins with an
understanding of the center of mass: the balance point
in which an object's mass is concentrated.
ORR: This is easiest to see in a completely symmetric object like
a basketball. The center of mass is at the center of the sphere.
As you get to objects which have less symmetry, it's a little
harder to figure it out, but it's still the center of where
the object is.
McHUGH: The center of mass for a figure skater is usually in the
hip area, well above the feet, or point of support.
ORR: Here we come to a situation which is unstable, and this is
what the figure skater actually has. Her center of mass is up
around her hips and her skates are touching the ice down here.
McHUGH: A figure skater's center of mass must be kept directly
above the point of support to maintain balance, adjusting as
positions change. This becomes even more challenging in pairs
skating and ice dancing, which require that both skaters keep
their centers of mass over the point of support through lifts,
throws, and complicated positions.
MERYL DAVIS: We like to focus on what's going to give us the most
potential to move quickly, spin quickly, achieve the most
aesthetically pleasing position. That is kind of based on where
our skating blade is, where our weight is sitting.
McHUGH: Isolating a skater's center of mass helps demonstrate
another physics principle found in figure skating: projectile
motion. When a skater performs a jump, he becomes a projectile -
an object moving vertically as well as horizontally - and his
center of mass will follow a curved path. This trajectory is
a mathematical shape called a parabola.
ORR: And it doesn't matter whether it's a baseball,
basketball, hockey puck or figure skater launched into the
air. The projectile motion will be this parabola universally.
It's gravity in all of these situations that make them
behave in the same way.
McHUGH: A skater is moving horizontally when she launches
herself into a jump and begins to move vertically. All the
while, gravity is pulling downward, decreasing the
skater's vertical velocity without affecting her horizontal
velocity. At the top of the arc her vertical velocity is zero.
ORR: The vertical velocity will be affected by gravity, whereas
horizontal velocity will be constant. And so those two
velocities - that which moves me horizontally and that which move
me vertically - are independent of one another.
McHUGH: The independence of vertical and horizontal motion
is another principle of physics that explains how pairs skaters
can perform amazing throws.
ORR: We have the pair of skaters coming along. He throws her in
the air. The motion along the ice is the same, and because
their motion horizontally is independent from the motion
vertically, they arrive at the same point at the same time.
So if we were to look at where she is at every instant in
time, she will be exactly over him, even though she's going up
and down and he's just moving across the ice.
McHUGH: In motion horizontally or vertically,
figure skaters give their all to accomplish the difficult
and demanding choreography.
LYSACEK: What does figure skating require? It requires
everything: massive strength combined with stamina, and then
you make sure you hit it every time under pressure while
the entire world is watching. It's a pretty difficult
sport, for sure.
McHUGH: Along with all the hard work, an understanding of
physics helps to keep these athletes skating toward
their Olympic dreams.
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