How to Use Magnets to Trap a Skittering Droplet of Liquid Oxygen

A liquid oxygen droplet flattens , rushes back and off , and then seems to be caught in an unseeable trap in the above video . Why does this happen ? There are two phenomena at work here : the Leidenfrost burden and paramagnetism .

You ’re most likely to see the Leidenfrost impression at breakfast , when you hot up up a pan for pancakes and see fall of water rolling across the surface like marble . The astragal of water are riding on a cushion of vaporization , allowing them to temporarily hover over the heat without getting boiled . To us , the drops are nerveless and the airfoil is red-hot , but it ’s the deviation in temperature that matters , not the temperature itself . The video shows a drop of cooled liquified oxygen undergoing the Leidenfrost event on a room - temperature surface .

Then along comes the magnet . Liquid atomic number 8 , like many other pith , is paramagnetic . This intend it shows no magnetised qualities when there are no magnetic playing area around , but bring in a magnet and the substance is draw in to it . The oxygen droplet flattens down to get near the magnet , or divert its grade to hover over it . This is what grant a speeding atomic number 8 drop to be decelerate , and then trapped , by a series of magnets .