Amazing anti-gravity water trick

A great, simple experiment to surprise both children and adults

Safe­ty pre­cau­tions

None.

Equip­ment

  • glass bot­tle with wa­ter;
  • piece of gauze (about 5 * 5 cm);
  • thin rub­ber band;
  • match­es.

Step-by-step in­struc­tions

Cov­er the neck of the glass bot­tle filled with wa­ter with a piece of gauze. Fas­ten the gauze in place with a rub­ber band. Cov­er the open­ing with one hand and turn the bot­tle up­side down. Re­move your hand. No­tice that the wa­ter doesn't leak out! Slip some match­es be­tween the holes in the gauze – the wa­ter still stays put!

Process de­scrip­tion

When we in­vert the closed bot­tle, a pres­sure equal to the sum of the at­mo­spher­ic pres­sure from the re­main­ing air and the pres­sure of the wa­ter col­umn is cre­at­ed in the neck. Thus, when we re­move our hand, the wa­ter in the bot­tle is in­clined to pour out. When a small quan­ti­ty of wa­ter pours out, the amount of air in the bot­tle grows. This de­creas­es the pres­sure from the wa­ter col­umn, and the flow of wa­ter stops. More­over, the force of the wa­ter’s sur­face ten­sion keeps the wa­ter con­tained in the bot­tle, thus pre­vent­ing air bub­bles from en­ter­ing the bot­tle.

The gauze on the neck, in fact, re­places one large hole with sev­er­al small ones, al­low­ing sev­er­al small droplets of wa­ter to form in­stead of one larg­er “drop.” These small­er drops pro­vide more re­sis­tance, against both the wa­ter pres­sure from above and the air flow from the at­mos­phere. When the sys­tem reach­es equi­lib­ri­um, the wa­ter stops leak­ing. When stick­ing a match into one hole in the gauze, we do not “break” the ten­sion of the wa­ter in the oth­er holes and there­fore the wa­ter is still held.

Try it