Ballpark — August 19, 2026

Average number of hairs on a human head

100,000 hairs

Blondes typically have the most, redheads the least.

Years a plastic bottle takes to decompose

450 years

PET plastic breaks down into microplastics but never truly disappears.

Weight of the air in an average-sized room

100 lbs

Air has mass, even if we don't feel it.

Books in the Library of Congress

26 million

Including manuscripts, maps, and music.

Miles of shoreline in the US state of Florida

1,350 miles

General coastline measure; a count that follows every island and inlet runs far longer.