Chapter 1
The math of the middle
Chapter 2
Sizing up the cosmos
Chapter 3
Engineering the everyday
YOUR GOAL
Master of The story of diameter
Ch 3 · Engineering the everyday
hue Coins use distinct diameters so vending machines and visually impaired people can easily identify different denominations.
hue Foresters measure a tree's diameter at breast height to estimate its age, health, and wood volume.
BETA
hue Drag the line across everyday circular items to learn how diameter defines their size.
Fun Fact
Tree trunk size: The General Sherman sequoia tree has a maximum ground-level diameter of 11.1 meters, making it wider than a three-story house.
Glossary
diameter (noun)
A straight line segment that passes through the center of a circle or sphere and has its endpoints on the boundary. A tree's resistance to snapping under wind loads scales with its trunk's diameter cubed.
A straight line segment that passes through the center of a circle or sphere and has its endpoints on the boundary. A tree's resistance to snapping under wind loads scales with its trunk's diameter cubed.
Quiz
What photographic effect is created by using a lens with a very wide aperture diameter?
Quiz
What is the name of the world's largest single-stem tree by volume, famous for its massive diameter?
Quiz
What standard height do foresters use to measure a tree's diameter at breast height (DBH)?
Quiz
In photography, what is the opening inside a lens whose diameter controls light intake called?