[Sally Le Page (OP)]

This week's question of the week comes from listener Henk:

"Is lava wet?"

We'd lava to hear what you think.

[Halc]

By definition, 'wet' means covered/saturated with water or other liquid.
So a the volcano in Iceland is definitely wet with lava.

Is water wet? Is it covered with water? Most people would answer yes, so then any liquid is equivalently wet.

[Bored chemist]

By definition, 'wet' means covered/saturated with water or other liquid.

What does a wetting agent do?

[Halc]

What does a wetting agent do?

Cries until you change it   

Seriously, a wetting agent is specific to water and other liquids with surface tension. The term 'wet' is more general than that.

[Bored chemist]

other liquids with surface tension.

So that's all liquids then...

Water isn't wet if you are made from wax.

The word "wet" has more than one meaning and so does "lava".
The technical meaning of the latter is molten rock  from inside the Earth (or another planet in some contexts).
So lava is never really in contact with liquid water- or at least- not for long.

Lava will certainly wet some things- notably things like basalt.
I don't think it wets graphite.

[Just thinking]

I'm not putting my hand in to find out. Lava will stick to things that are porous it has some of the qualities of water in that lava can flow but I think that lava is further away than it is close to being wet.

[obie]

That question is pure poetry. Concise and thought provoking (bar specialists). Less is more. Something is flowing.

[alancalverd]

Wetting means having a contact angle less than 90 degrees.

[Sally Le Page (OP)]

Thanks for your responses. Geologist Brooke Johnson answered this question on our show, and you can listen here:

https://www.thenakedscientists.com/podcasts/question-week/lava-wet [nofollow]