Brain Teaser: A Battle Over the Great Lakes

Buy an ad on DigitalJournal.com

Some History

I have known about this one for years and I expect anybody who enjoys puzzles has heard it at one time or another. It doesn't require any math at all. Some science knowledge will help but even that is not really necessary.

THE PROBLEM

Hypothetically speaking, let's imagine that Canada and the US got into a big fight over the Great Lakes. Both sides send some battle ships into Lake Erie and then manage to block off every waterway into and out of the lake (did I mention this was a hypothetical scenario?)

During the battle all the battle ships are sunk, not a single one is left above water.

Ignoring the effects of evaporation (if we can really isolate a Great Lake then we can obviously stop evaporation too) would the water level of the lake after the battle be higher, lower, or the same as it was before the battle began?

In other words, when a bunch of battle ships sink does that make the water in the lake go up, down, or stay the same?

I'll post the answer in the comments in a few days. If anybody knows the answer, has a question, or whatever, they can post a comment but if you want people to know you know without giving away the answer feel free to send me an email and I will list everybody who got it right when I post the answer.

Happy Thinking.