Rice grip

Can rice hold a bamboo stick?

Safe­ty pre­cau­tions

Warn­ing! Only un­der adult su­per­vi­sion

Equip­ment

  • plas­tic bot­tle;
  • rice;
  • fun­nel;
  • chop­stick.

Step-by-step in­struc­tions

Fill a plas­tic bot­tle to the brim with rice. Then, clos­ing the open­ing with one hand, tap the bot­tle on the ta­ble sev­er­al times to make the rice set­tle in place. The vol­ume of rice in the bot­tle should de­crease. Add more rice and tamp it down again. Then in­sert a chop­stick into the rice and try to pull it back out again. The stick lifts the bot­tle eas­i­ly!

Process de­scrip­tion

Fric­tion­al force aris­es when two bod­ies come into con­tact and in­ter­feres with their move­ment rel­a­tive to each oth­er. In this ex­per­i­ment, the chop­stick and the rice are two such bod­ies. When the rice is tamped down, it be­comes quite dense, and when the chop­stick is in­sert­ed the rice has nowhere to go: the bot­tle lim­its its move­ment. The rice squeezes the stick firm­ly from all sides and a strong fric­tion­al force aris­es, which is ca­pa­ble of sup­port­ing the bot­tle. It is worth not­ing that fric­tion­al force also aris­es if the rice is un­com­pressed, but it is much weak­er, be­cause the un­com­pressed rice press­es less on the stick.

Cool ex­per­i­ments await you in the MEL Physics sub­scrip­tion!

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