How to make flame levitate

Warn­ing! Only un­der adult su­per­vi­sion

Equip­ment

• ball­point pen;
• lighter.

Step-by-step in­struc­tions

Re­move the ink car­tridge from a pen and pull out its tip. Cov­er a lighter’s noz­zle with ink and click the lighter – the flame lev­i­tates!

Sci­en­tif­ic de­scrip­tion

Ink has high vis­cos­i­ty, so if you use it to cov­er a noz­zle that is re­leas­ing gas, it de­creas­es the noz­zle’s di­am­e­ter, which in­creas­es the ve­loc­i­ty of the gas flow and de­creas­es the oc­cur­rence of in­ho­mo­geneities in the flow. This pre­vents the com­bustible gas from mix­ing with oxy­gen from the sur­round­ing air at the base of the jet, and, as you know, there can be no fire with­out oxy­gen. There­fore the in­ho­mo­geneities, and thus the flame, form in the up­per sec­tion of the gas jet, which is slowed by the vis­cos­i­ty of the air!

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