Fermi Questions Marathon

[hmcginny]

So when you sneeze you expel maybe 100 ml of gas and a little bit of liquid/solid. most of what you release is in the form of carbon dioxide, and 100 ml of gas is probably E0 moles of carbon dioxide, the solid is probably another E0 moles, but together they add to E1. E1 moles is 6E24 so E25 molecules.

How many blades of grass are there in Central Park, NY?

[3nv1r0nm3ntal ch3m]

Central park is about 5E0 km2 (i think) and I'll say there are 3 blades of grass per cm^2. 5E0 km^2 is 5E6 m^2 and 5E10 cm^2. when multiplied by 3, i get 1.5E11, or E11 as my answer.

how many moles of molecules are in a single human arm hair.

[Angstrom]

The fiber is itself made up of intertwined long strands of keratin, each of which is one large molecule and whose size I'm not sure how to calculate. Off a vague guess, I would say E3 individual strands make up an arm hair, so that would be E-20 moles. It's not a derived guess though, so probably terrible.

How many times is the ampersand typed each day within Rice University's campus?

[hmcginny]

so Rice is around 4E4 people including faculty? thats just a guess but its definitely E4 people. Ampersand is not that common a symbol to type, so i'd say maybe each person types it around once a day, so lets call that E4 times per day.

How many trees are there on earth?

[Schrodingerscat]

If I recall, the radius of the Earth is 4E3 km, and surface area is 4pi*r^2, so 1E8km^2, 70% is water, and a good fraction of the land is deserts, plains, and tundra, however I will guess the Earth is a few percent forest, so that is 1E6km^2 of forest. If a tree covered 10m^2, thats 1E5 trees per square kilometer, Therefore, I will say 1E11 trees.

How many hours would it take a 1 square meter solar panel on Earth to collect 1 Joule of energy from the star Sirius?

[Marble101]

Sirius is the brightest star in the Night Sky aside from the Sun.
I'd hazard a guess that E3 joules of energy hit the earth from it every day. (Probably a terrible guess)

The earth's radius is 4E3 km. So, 4*pi*4E3*4E3 is about E7. this is 10^10 times bigger than 1 sq. meter of solar panel. So E3/E10 = E-7.
Thus, I say E(-7).



If Google donated all of its money to Microsoft, how many math textbooks could Microsoft now buy?

[cngu23]

Sirius is the brightest star in the Night Sky aside from the Sun.
I'd hazard a guess that E3 joules of energy hit the earth from it every day. (Probably a terrible guess)

The earth's radius is 4E3 km. So, 4*pi*4E3*4E3 is about E7. this is 10^10 times bigger than 1 sq. meter of solar panel. So E3/E10 = E-7.
Thus, I say E(-7).


If Google donated all of its money to Microsoft, how many math textbooks could Microsoft now buy?

Google has like 5E10 (they bought Youtube for like 15E9 and make 2-3 billion a year) and a math textbook is 1E2 so Microsoft could now buy 5E8 math textbooks.


Question: How many text messages are sent every week by students in University of Michigan?

[hmcginny]

The average student sends around E1 per day so 7E1 or E2 per week. I'd assume there are around 1E4 students at the University of Michigan, so E6 text messages per week.

How long is the US highway system in centimeters?

[ionocraft]

Since the us highway system has about 46,602 miles in it; this translates to about 75,000 km, and then into 7,500,000,000 cm, my answer is E10.

my question is... How many kilograms of popcorn does the average American eat in a year.

[Marble101]

Since the us highway system has about 46,602 miles in it; this translates to about 75,000 km, and then into 7,500,000,000 cm, my answer is E9.

my question is... How many kilograms of popcorn does the average American eat in a year.

I will ignore all popcorn not eaten in movies since it's amount is probably negligible.

America has 3E8 people in it. Some people go 2-3 times a year, some none, and some 9-10 times, so I'll say the average american goes to watch a movie 6 times a year. This makes E9.
Each popcorn tub probably weighs E-1 kg, so I say E8.

How many times has the SAT been taken in the past 5 years?