How to inflate a balloon without touching it

Inflate a balloon inside a bottle!

Safe­ty pre­cau­tions

Warn­ing! Only un­der adult su­per­vi­sion.


  • glass bot­tle;
  • bal­loon;
  • boil­ing wa­ter.

Step-by-step in­struc­tions

Pour some boil­ing wa­ter into a glass bot­tle and wait un­til the glass warms up. Pour out the wa­ter and put the bal­loon on the neck of the bot­tle. Af­ter a while, the bal­loon will be drawn into the bot­tle, and then it will in­flate!

Process de­scrip­tion

In putting the bal­loon on the neck of the bot­tle, you cre­ate a closed sys­tem. This sys­tem has a fixed amount of air and a tem­per­a­ture high­er than the am­bi­ent tem­per­a­ture. When the glass cools down, the air in­side the bot­tle cools as well. With it, the pres­sure de­creas­es, be­com­ing low­er than at­mo­spher­ic pres­sure. At­mo­spher­ic pres­sure “in­flates” the bal­loon into the bot­tle.

A lot more cool ex­per­i­ments are wait­ing for you in the MEL Physics sub­scrip­tion!