[scientizscht (OP)]

Simplest method is to look at the color of seaweed.

How can you be sure that seaweed color is only dependent on acidity and whether such relationship is linear?

[Bored chemist]

whether such relationship is linear?

Nobody will have assumed that it is.

How can you be sure that seaweed color is only dependent on acidity

It probably isn't.
For example, it probably depends on temperature, but you can measure that independently, and correct for it.

Omg I told you it's an acid.

Actually, sea water is slightly alkaline.

They apparently measure ocean's acidity from space so I wanted to know how they do that.

Why didn't you ask that then, rather than posting gibberish?
You seem to do this a lot.
Why?

[The Spoon]

Thanks but I said remotely, the solution is in a bottle that need to be sealed!

So why did you say:

Thanks but I said remotely, the solution is in a bottle that need to be sealed!

[jeffreyH]

Simplest method is to look at the color of seaweed.

The eyes have it. Motion passed.

[jeffreyH]

@scientizscht How old are you? I'm curious.

[scientizscht (OP)]

@scientizscht How old are you? I'm curious.

That's personal and ageist. Unless you mean mental age.

[The Spoon]

@scientizscht How old are you? I'm curious.

That's personal and ageist. Unless you mean mental age.

It may be personal, but asking somebody's age is hardly ageist. Unless you are trying to shut down criticism?