How can you expand marshmallows

Use the power of emptiness!

Warn­ing! Only un­der adult su­per­vi­sion


  • vac­u­um cham­ber;
  • marsh­mal­lows.

Step-by-step in­struc­tions

Seal some marsh­mal­lows in a vac­u­um cham­ber, make sure the vac­u­um cham­ber valve is closed, and pump the air out with a pis­ton. The marsh­mal­lows ex­pand! Open the valve and watch as the marsh­mal­lows de­flate.

Sci­en­tif­ic de­scrip­tion

When you lift the pump han­dle, air from the vac­u­um cham­ber is drawn into the sy­ringe. When you low­er it, you force the air out into the at­mos­phere. The valve sys­tem lets air out from un­der the hood but doesn’t let it back in. Marsh­mal­lows have a por­ous struc­ture – they con­tain in­nu­mer­able bub­bles filled with gas. In pump­ing air out of the cham­ber, you low­er the pres­sure in­side. When the pres­sure in­side the bub­bles is greater than the pres­sure out­side them, they be­gin to in­crease in size, in­flat­ing the marsh­mal­lows. If you open the valve and let air back into the cham­ber, ev­ery­thing will de­flate: the at­mos­phere will squeeze the in­flat­ed bub­bles to their orig­i­nal size, and with them, the marsh­mal­lows them­selves!

Cool ex­per­i­ments are wait­ing for you in the MEL Sci­ence sub­scrip­tion!