So where did all the salt originate?
Essentially the salt is part of the process where we have fresh water on land, running toward the ocean carrying nutrients/minerals (including salt) into the ocean.
Put that on auto for a few million years and you have the current ocean.
We get the word salary from salt too
"The Old English ending -wic ... means farm, as in Keswick (cheese farm), or Goswick (goose farm) ... but it might denote a periodic, opportunistic beach market ... for example Lundenwic (London), Gypeswic (Ipswitch) and so on."
When had most of the salt dissolved into the sea?
I left out lots of stuff, like chemical weathering, thermohaline circulation, glacial damming, and Milankovich cycles which probably explain a lot more... but I’m a climatologist not a geologist so there’s a whole lot more about the chemistry I don’t understand.
Hazen's mineral evolution story was made into a NOVA. Some years back, before the NOVA, it had anecdotally been used down to high-school, but he didn't know of any attempts at middle or primary school. But it seems the usual science education dynamic is no one trying, or doing a miserable job of it, rather than hitting a rigid accessibility envelope.
The cluefulness cost space can be surprisingly shaped. Teach a 5-year old that sunlight is white, and so is the Sun, and after that second bit, they're already less confused there than most first-tier astronomy and physical sciences graduate students. I suggest we've little idea yet how early much of science might be taught, because we've been half-assing it.
And pedagogy.
This might be misread as a primordial origin event. Ocean chlorine and sodium residence times are under 100 Myr. So an ongoing process, with rocks dissolving, and excess precipitating.
Bilions of tourists urinating in the water.