Blueprinting, which has been around since 1842, is a common way to reproduce an architectural drawing. Tune in to learn more about the complex chemical processes that make blueprints blue -- and white -- in this podcast from HowStuffWorks.com.
Learn more about your ad-choices at https://www.iheartpodcastnetwork.com

What Pranks Have Astronauts Pulled?
08:40

How Can Your Body Learn to Tolerate Cold?
10:58

How Did the War of 1812 Settle the American Revolution?
10:23