Fermi Questions

World Population

8E9

USA Population

3E8

Pennsylvania Population

1E7

Philadelphia Population

2E6

NYC Population

8E6

Earth Radius

6E3 km
4E3 mi

Earth Circumference

4E4 km
2E4 mi

Earth Surface Area

E15 m^2
E9 km^2
2E8 mi^2

Moon Radius

2E3 km
1E3 mi

Sun Radius

7E5 km
4E5 mi

USA Area

4E6 mi^2
1E7 km^2

Pennsylvania Area

5E4 mi^2
1E5 km^2

Philadelphia Area

1E2 mi^2
4E2 km^2

NY to LA distance

2E3 mi
4E3 km

Philadelphia to Erie distance

3E2 mi
5E2 km

Speed of Sound (dry air, 20 Celsius)

340 m/s
770 mi/h

Speed of Light

3E8 m/s

Seconds in a Day

9E4

Seconds in a Year

3E7

Feet in a Mile

5280
(Five Tomatoes)

Kilometers in a Mile

1.6 km = 1 mile

Acres in a Square Mile

640 acres = 1 mi^2

Centimeters in an Inch

2.5 cm = 1 inch

Kilometers in a Light Year

1E13

Light years in a Parsec

3 ly = 1 pc

Earth to Sun distance

1 AU (astronomical unit)
1E8 km

Earth to Moon distance

4E5 km

Milky Way Diameter

1E5 ly
1E18 km

Mass of the Earth

6E24 kg

Mass of the Moon

7E22 kg

Mass of the Sun

2E30 kg

Visible Light Wavelength

5E-7 m
5E2 nm

X-Ray Wavelength

1E-9 m
(1 nm)

Microwave Wavelength

1E-2 m
(1 cm)

What's nu?

c over lambda!

Width of Human Hair

1E-2 cm
1E-4 m

Watts in a Horsepower

750 watts = 1 hp

Power consumption of an average American home

3E4 Watts (Joules/second)

Household microwave power consumption

1E3 Watts (Joules/second)

Sun power output

4E26 Watts (Joules/second)

Height of Mt. Everest

9E3 m
3E4 ft

Height of the Empire State Building

4E2 m
1E3 ft

Height of the Burj Khalifa

8E2 m
3E3 ft

Height of the Statue of Liberty

3E2 ft
1E2 m

Height of the tallest tree
(Hyperion, a coastal redwood)

1E2 m
4E2 ft

Depth of the Mariana Trench

1E4 m
4E4 ft

Volume of an Olympic Swimming Pool

3E6 Liters
3E3 m^3
9E4 ft^3
50m x 25m x 2m

Liters in a Cubic Meter

1000 L = 1 m^3

Age of the Universe

1E10 years

Age of Earth

5E9 years

Diameter of an Atom

1E-10 m
(1 Ångström)

Diameter of an Animal Cell

1E-5 m

Cells in the Human Body

3E13

Number of McDonald's in the US

1E4

Faraday's Constant

1E5 Coulombs/mol e^-

Charge of an electron

-2E-19 Coulombs

Avogadro's Number

6E23 units/mol

Universal Gravitation Constant

7E-11

Mass of an electron

9E-31 kg

Mass of a proton/neutron

2E-27 kg

Red Blood Cell Count

5E6 per E-6 L

Red Blood Cell Diameter

E-5 m

Volume of Blood in Body

5 L

Number of Neurons in Body

E11

Number of Synapses in Body

E14

DNA in Human Cell...

E0 m, 3E9 base pairs, 3E4 genes

SA (Surface Area) of skin on Human

E0 m^2

Virus Diameter

E-7

Bacteria Diameter

E-6 to E-5 (usually E-6)

Total Volume of a Human

E2 L (approximately 62 L)

Total Volume of ALL Humans

E11 L (almost E12)

Total Length of ALL Blood Vessels

E8 m

Bohr Radius (Hydrogen Atom Radius)

5*E-11 m (E-10)

Mass of All Man-Made Objects

E15 kg

Volume of Breath inhaled per Breath

E0 L (0.5 L)

Volume of O2 produced by Trees

E5 L/year

Mass of Grain of Sand

E-5 kg

Volume of Grain of Sand

E-10 m^3

Number of Grains of Sand on Earth

E19 grains

Grass count

E8 blades/acre (acres of grass)

Number of Atoms in Human Body

E28 atoms

Number of Text Messages Sent in a Day

E10

Number of Text Messages Sent in a Year (USA)

E9

Average Word Count of a Novel

E5 words

Thickness of Cardboard

E-3 m

Number of Songs in The World

E8 songs

Songs Released per Day

E5 songs

Total Volume of Freshwater

3.5E19 L

Total Volume of Oceans

1.4E21 L

Total Volume of Water on Earth

1.5E21 L

The Great Lakes

Volume: E16 L, SA: E11 m^2

GDP of USA

E13

GDP of China

E13

Farmable Land in USA

3.5E12 m^2

Livestock Population in USA

E8

Number of Active Volcanoes on Earth

E3

Number of Dormant Volcanoes on Earth

E3

Number of Super-volcanoes on Earth

E1

Thickness of a Coin

E-3 m

Thickness of Hair

E-4 m