weightlessness

weightlessness, or an absence of ‘weight’, is in fact an absence of stress and strain resulting from externally applied mechanical contact-forces, typically normal forces from floors, seats, beds, scales, and the like. A uniform gravitational field does not by itself cause stress or strain, and a body in free fall in such an environment experiences no g-force acceleration and feels weightless. This is also termed “zero-g” where the term is most correctly understood as meaning “zero g-force.”

• accelerometer
• free fall

What’s the problem?
Zero-G Espresso Cup Developed for the ISS – micro-gravity drinking cups.

• Ask – The new design makes possible the enjoyment of espresso and other drinks in the low-gravity environments of spacecraft.
• Imagine – Without the pull of gravity, fluids behave very differently than on earth. Instead of ‘pouring,’ a liquid retains a more globular shape held together by its own surface tension. This phenomenon complicates even the most basic of maneuvers such as drinking a cup of coffee.
• Design, Build – The 3D-printed espresso cup is designed to cheat low-gravity by channeling liquid along a specifically-calculated contour in the vessel to exploit capillary forces that simulate the action of pouring. “Its geometry is the ‘smart’ part, which provides the fluids-control system without requiring pumps or centrifugal forces,” explains Weislogel. “The shape of the container can passively drive fluids to desired locations without moving parts—exploiting the passive forces of wetting and surface tension.”
• Improve –

That’s engineering

• g-force – (g from gravitational) – a measurement of the type of acceleration caused by mechanical contact-forces between object surfaces, and that indirectly causes weight. g-force is not a force. “g-force” is a type of acceleration that can be measured with an accelerometer.
• zero-g or “zero g-force” – absence of stress and strain resulting from externally applied mechanical contact-forces
• micro-gravity – indicates that g-forces are not quite zero, just very small
• gravitation – a force of attraction between any two masses; the act or process caused by this force

Engineering ideas

• zero gravity (Zero-G), micro-gravity, surface tension, liquid, channel, contour, capillary forces, simulate, geometry, fluids-control system, pump, centrifugal force, passive force, wetting, surface tension, accelerometer

Do It
Challenges for you to work on…

• find examples of innovative solutions to everyday activities and objects modified for use in the weightlessness environment of the International Space Station (ISS)