Solutions The exhibition at the Cooper-Hewitt has many items to show a grasp of the depths of world poverty and ingenious ways to attack it. They include a 20-gallon rolling drum for transporting water, above.

A pot-in-pot cooler that relies on the evaporation of water from wet sand to cool the inner pot.

The Lifestraw drinking filter, which kills bacteria as water is sucked through it.

To that end, the Cooper-Hewitt National Design Museum, which is housed in Andrew Carnegie’s 64-room mansion on Fifth Avenue and offers a $250 red chrome piggy bank in its gift shop, is honoring inventors dedicated to “the other 90 percent,” particularly the billions of people living on less than $2 a day.

Their creations, on display in the museum garden until Sept. 23, have a sort of forehead-thumping “Why didn’t someone think of that before?” quality.