Science and technology experiments
conducted by NASA aim to provide significant health and safety benefits
for astronauts and spin-off technologies to improve life on Earth.
Sometimes the experiments themselves attract broader attention because
they are so visually captivating and thought-provoking.
Glenn Fluid Mechanics Scientist, Dr.
Mark Weislogel, and his team of researchers burst approximately
50 water balloons over a four-day flight campaign aboard
a DC-9. Over the last 10 years, footage from the water
balloon experiments has been used in textbooks, scientific
journals, and classrooms worldwide. Aside from looking
“really cool,” these water balloon experiments show how
large liquid drops behave in a low-gravity environment
and how easily and rapidly they can be deployed. Experiments
and demonstrations like these are precursors to large-scale
large liquid drop deployment tests that might be considered
for future space experiments on exploration missions.
Click on the links below
to view high-speed photography of punctured
water balloons at high speed (1000 frames/sec)
in a laboratory:
A 15cm diameter water balloon is ruptured using
a syringe needle. At least in the short term, the retracting
membrane leaves the bulk liquid intact and very spherical. A
spray (mist) of drops is ejected in the direction of the membrane
A sausage-shaped water balloon is ruptured
near its midpoint. The balloon unwraps from the water in stages
as it rips in two. A "fan" is produced near the puncture
location where fluid from left half of the balloon is forced
into the right half.
Symphony of Spheres on
the International Space Station
During Dr. Donald Pettit's nearly
six-month flight (from November 2002 – May 2003) on-board
the International Space Station, he conducted many experiments
and demonstrations for the Saturday Morning Science Program.
His “Symphony of Spheres” is an excellent illustration
of the fluid physics experiments that can be performed
in microgravity, as opposed to a 1-g, low-gravity environment.
Don's comments about his “Symphony of Spheres” included:
“Created inside the air bubble were a half-dozen or so small
spherical droplets of water, one to four millimeters in diameter,
orbiting around like a miniature solar system. … This motion
appeared almost life-like so that for a minute I thought we
were looking through a magnifier at some new form of creatures
zooming around inside of a three-dimensional Petri dish. …
Of all the things on orbit I have seen to date, this is by
far the most amazing.”
Drop coalescence is so strongly hindered by the absence of
gravity that it poses a unique challenge for engineers designing
fluids handling equipment for spacecraft.
Dr. Pettit investigates the behavior of
large air bubbles inside spheres of water on a 50 mm wire loop.
A large bubble is formed by injecting air into a water sphere.
Oscillations of the interior water/air surface can be seen
as air is injected making the air bubble larger.
Water spheres are created inside the air
bubble inside the water sphere on a 50 mm wire loop. These
small water spheres (approximately 2-6 mm) are seen to ‘roll
around' the exterior of the air bubble and bounce linearly
off the air bubble exterior. These small spheres also collide
in ‘mid-air' without coalescing. The small water spheres eventually
slow down and coalesce when they collide with each other or
the large water sphere.
A small water sphere (approximately 5 mm)
rolls around the exterior of an air bubble inside the 50 mm
water sphere held in place by a wire loop. The small water
sphere speed slows until it coalesces with the large water
sphere at which point an even smaller water sphere (about 3
mm) is ejected and begins bouncing around inside the air bubble.
A small water sphere (about 5 mm) rolls
around the exterior of an air bubble inside the 50 mm water
sphere. The path of the small water sphere is in a vertical
plane nearly aligned with the camera. Other smaller water spheres
are also faintly seen rolling around the air bubble exterior.