Our tuna for lunch made for a spontaneous consumer education project.
After draining two cans of tuna we poured the water back into one of the cans. We found out that the tuna can contained about half of it's volume in water. We saw that the water didn't come all the way to the top but then the can isn't completely full as it does make a sloshing before opening it indicating open can space. Assuming that amount two times would be about the amount we are missing after pour two cans of water into one, we decided it was close enough to say that a can of tuna is half water added the fact that getting all the water out of the tuna isn't possible with our draining method.
Our tuna was the in the 5 ounce can so there would be 2.5 ounces of tuna in each can. That alone made us wonder by itself how that could be two servings. For this we figured that it would take 6.4 can of tuna to make one pound of just the tuna. We can buy tuna for about 63 cents a can. That would make tuna cost about $2.02 a pound. That doesn't sound too expensive, actually quite inexpensive for a protein considering other options.
However, on my counter I also have tuna water that cost $2.02 per pound as well. Not that it goes to waste, the cats love it although normally I wouldn't spend that much to give them a little treat. Actually, I would never spend that much to give them a treat but that is neither here nor there for our purposes.
Would I spend that much for other fluids? For example, a gallon is about 8 pounds, would I buy milk if it was $16.13 a gallon? Umm, that is a capital N-O. How about $8.08 for a 2 liter bottle of soda? Again no. The only thing that maybe comes close, and we do buy, is cream (which does come to about $1.94 per pound depending on where we are shopping) but, I don't feed it to the cat and it is actually a food and not just dirty colored water that if I didn't have a cat would dump down the drain.
On the other hand the tuna juice is a bargain compared to contact lens lubricating and re-wetting drops that come in at a whopping $446.72 per gallon! And you thought gas was expensive.