186. The North Pole has six months of uninterrupted darkness every year.

Desalination. Six gallons of desalinated sea water renders about 1.75 pounds of salt.

Hyena. Hyenas are more closely related to cats, but behave like dogs.

Indian Summer. "Indian Summer" occurs after the trees have lost their leaves, but before snowfall.

4.184. Calories are units of heat energy.

Generator. A generator converts mechanical energy to electrical energy.