Due to the changes in surface tension and the charge concentration on the mercury( the top gif ) and the gallium drop, it contracts and relaxes. This phenomenon is fondly referred to as ‘The beating heart’ by Fluid Dynamicists.
Happy Valentine’s day!
Time is too slow for those who wait, too swift for those who fear, too
long for those who grieve, too short for those who rejoice, but for
those who love, time is eternity.