Henk asked "Is lava wet?"


Sally Le Page spoke with geologist Brooke Johnson from the University of Oxford to find out more...

Brooke - The dictionary definition of wet is “covered or saturated with liquid” which makes sense when you think of water. If you get in the shower and turn the tap on, you definitely get wet pretty quickly. If you’ve seen videos of lava, you’ve seen how runny it can be. It certainly looks like a liquid, but lava is not actually a liquid. Lava is molten rock it’s more like a very gooey solid. Like toffee, but heated to a thousand degrees, and made of minerals.

Sally - Mmmm, imagine a volcano that erupted rivers of toffee...

Brooke - So, in the strict definition of things, lava can’t be wet because it’s not a liquid, it can’t make things wet or saturate them. If you watch a video of something getting thrown into lava, it doesn’t go “splash” and sink, it goes “thud” and then bursts into flames.

Sally - I can confirm having just spent far too much time watching videos of people throwing random objects into lava, that they do just go thud and burst into flames.

Brooke - Lava is made of minerals, minerals are inorganic naturally occurring solid materials, that have defined chemical ingredients, and a defined crystal structure. That means that water ice is a mineral, and that means that water is a type of lava.

Sally - I’m just going to repeat that because it is mind blowing. Ice fits the definition of a mineral. And so by definition, water is a type of lava. Water is lava. My brain just erupted.

Brooke - By that logic you could rephrase the question as 'is water wet' which is the sort of philosophical question I don't think anyone can answer. So, is lava wet? Usually not, but it can sometimes be water.

Sally - Moving from red hot to red spot, next week’s question of the week comes from Ruomei

Ruomei - Why do ladybugs have different numbers of spots on their backs?


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