ILLUSTRATES cloaked
SUGGESTION Gabriel Fagundes
1. By pressing it against the wall, we expel much of the air between the cone and the surface. Thus, the air pressure outside the cup becomes greater than that in the inner area. This pressure acts perpendicular to the surface, from outside to inside. Result: it is fixed to the wall
two. The suction cup is a great design case. O conical shape, half rounded, makes it resistant to pressure differences, prevents it from breaking and helps to distribute forces equally over its entire surface. The composition material (such as rubber, vinyl and silicone) also helps. And the larger the contact area of the suction cup, the lower the internal pressure. In other words, big ones are more effective.
3. The ideal is to stick it on a smooth surface, free of irregularities. If there are small grooves on the surface, air can gradually enter through there and raise the pressure, “unseating” the cup. That’s why it’s worth wetting it before installing it: the water occupies the spaces, making the surface smoother
4. This fixation system is a process similar to the formation of a vacuum, when the pressure inside a container is negligible in relation to the outside. However, it is not possible to achieve full vacuum in a domestic vacuum cleaner. Gradually, the air always enters and, more days, less days, she gets loose
THE SUPER WINDOWS
Army creates powerful versions to apply to rescue robots
The US Army Research Laboratory has developed self-sealing suction cups, coupled with suction pumps. Thus, even those that do not adhere to the surface close automatically after removing the air. The first prototypes, ultra-small, are being applied in the hands of robots that can help, for example, in rescuing victims of landslides
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CONSULTANCY Jorge Deveikis Junior, graduated in Physics (USP) and Master in Science Teaching (USP)
SOURCES UFMG Department of Physics, UFRGS Institute of Physics, US Army, Anver and EDCO USA websites