Is Coca Cola copyrighted because the ingredients aren't secret- they're printed on the can!
Well, when you say copyrighted I assume you mean protected from someone else making their own Coke and selling that as their own.
Copyright subsists on works of art like plays, music, writing like poems, books, stories and so on. Copyright exists so that someone can't pass off your work as their own. Since Coca Cola the product isn't a work of art then you can't copyright the drink. You could copyright a jingle from one of their ads for example but not the drink itself.
Coca Cola certainly has a trademark. A trademark is protection under the law of your company's "brand"- think of the coca cola font, the shape of their bottles, their slogans, etc. All of these things together are the Coca Cola brand and they are protected by law because they belong to Coke. The brand is what distinguishes Coke from other similar drinks like Pepsi. The trademark has got nothing to do with the product itself though.
Youre right that the ingredients of Coca Cola are on the can, but that doesn't mean that you can make it. Not because I doubt your creativity but because to create something you not only need to know what is in it but also how you put the ingredients together- in essence, the process of manufacture. I could tell you that a cake has eggs, milk, flour, sugar, and chocolate but if you don't have the recipe of how to put those things together then you don't have a cake!
The legal instrument that protects a method of manufacture is called a patent. A patent gives people who design products like Coke or an iPhone, or a food, a right to protect their new method of manufacturing or designing products for a period of time, usually seven years.
The idea is that after seven years a designer or manufacturer will have protection so that only they can sell their product. When other companies, after seven years, want to compete by making the same product they will be disadvantaged because original designer would already have a foothold in the market. Patents protect inventions for a while, but then they are opened up so that other people can tinker with them and theoretically make the original invention better.
Applying for patents is really involved and complicated and they are usually (usually) valid internationally. So if you took a patent out in Australia you could enforce it anywhere.
Coke does not have a patent for it's drink- why? Because to take out a patent over something you have designed or created you need to disclose how it's made. The process of manufacture can't be secret if you want patent protection. As I mentioned above, patents only provide protection for so long, after that your invention is opened up to the market so that it can keep evolving.
What that would mean for Coca Cola is that they would have to put it's secret formula out there for the world to copy if it wanted patent protection over it. Logic tells you that they really, really, don't want that.
So Coke is not copyrighted because copyright only exists for works of art. What you mean to ask is, is Coke patented?
The answer is no, because to take out a patent Coke would have to disclose how it makes its best selling product. They don't want that! Even if you knew the secret recipe and you tried to pass it off as Coke you wouldn't be able to as the intellectual property laws that protect such establish brands like Coke are incredibly strong.
Coke is disgusting anyway, drink water instead!