Last Week's Question - - (submitted by Marc A) Why does a liter of water weigh a kilogram?

Mimi P - Sorry to state the obvious, but pure water's density is 1g/mL or 1g/cc. Isn't it weird how the metric system works so well? It may very well have been random (doesn't seem like it; you can't dispute density!), but it makes a whole lot of other calculations (i.e., buoyant force) a whole lot easier. Water is important, dude. Specific gravity is another example...

Stephen P - Why does a liter of water weigh a kilogram ?

To find out how much it weighs .

Some thing akin to why does a squirrel cross the road ?

Jim W - If the liter of water is in some gravitational field, it must weigh something. Why not a kilogram?

This Week's Question - Ok, historical landmarks are great. Signs that tell us about historical landmarks are dandy too (Hooray for background information, no?). But do we really need signs on the road to tell us that "Historical Landmark Signs are Ahead?" (And yes, some states have them).