Common Orders of Magnitude

Questions on the order of magnitude have been quite popular in O-level Physics examinations in recent years. Here's a list to help my readers:

Length / m
Diameter of proton ~ 10^-15
Radius of typical atom ~ 10^-10

Diameter of red blood cell ~ 10^-5

Thickness of hair/paper  ~ 10^-4

Length of soccer field ~ 10^2

Radius of Earth ~ 10^6

Diameter of Earth ~ 10^7

Mass / kg

Mass of electron ~ 10^-31

Mass of proton~ 10^-27

Mass of typical atom ~ 10^-25

Mass of 5 cent coin ~ 10^-3

Mass of apple ~ 10^-1

Mass of car ~ 10^4

Mass of bus ~ 10^5

Mass of Earth ~ 10^24

Time / s

Length of a day ~ 10^5

Anyway, here's a website where you can find out the order of magnitude for other physical quantities (http://hypertextbook.com/facts/index-topics.shtml) and here's a book on how order of magnitude can help you to make good estimates (https://www.bookdepository.com/Guesstimation-Lawrence-Weinstein/9780691129495).