Kasia's Corner

Doesn’t this remind you of ‘Flubber’, the movie?

Since this will be the last post of Kasia’s Corner before the holidays, I will be sharing a fun (as always) experiment that may need a little more time to investigate, however worth it all the while!

The Leidenfrost effect is the phenomenon of how water can glide on any surface it rests on, essentially allowing it to flow uphill. This is because when water is heated past its boiling point, but doesn’t evaporate, steam forms a layer of insulation between the liquid water and the surface it rests on. When this effect occurs on ridged materials, the gliding water moves in a funky way that makes it look like its cha-chaing (real smooth) across the surface!

Isn’t that so cool? Well, actually this happens by heating water, so its actually pretty hot…

The Leidenfrost effect is not limited to water; it can occur for other liquids as well, however the effect depends on the varying boiling points of liquids. Therefore, for this week, let’s roll up our sleeves, put on our goggles, and get to work by observing how the boiling points affect the Leidenfrost effect! Ah, to be a budding scientist making water dance (and doing a sneaky little jiggle together with it)!

REMEMBER: Wear eye protection and be careful when using the stove- just because the summer heat will be burning, doesn’t mean we should be as well.

1. Prepare four small cups of:
   1. 10ml tap water + 10ml 70% ethyl Alcohol (you can find it at the pharmacy) mixed well
   2. 20ml white vinegar
   3. 20ml bottled water
   4. 20ml tap water + 5g table salt mixed well (its okay if the salt doesn’t fully dissolve)

You can use food colouring to separate the mixtures apart (and make it look cool)

2. Sprinkle some talc baby powder on a pan (to reduce splatter- don’t worry! It washes off easily)
3. Using a spatula, make four ‘wells’ to separate your droplets
4. Starting with low heat, drop a single droplet of each solution into its own well and see what happens
5. Keep on dropping and observing as you gradually increase the heat every 3-5minutes. Top tip: remember to look for the evaporation time, simmering, boiling, splattering and droplet formation each time!
6. When your droplets stop sizzling or evaporating, but instead float on steam- voila! You’re looking at the Leidenfrost effect in full action.
7. Turn of the heat and let it cool before washing up

So? What did you notice? Did you notice any Leidenfrost droplets shrinking? Which solution started sliding and grooving first? And last?

Please, pretty please, do try this at home to become a chef-scientist-wizard by trying this experiment and email me what you found out at Katarzyna_Murawska@thebritishschool.pl

Adios,

Kasia