Midterm Numbers To Know Flashcards
watts per human power
100
melting/freezing temperature of water
273.15 k
boiling point of pure water at Earth’s atmospheric pressure
393.15 k
the approximate mechanical efficiency of most engines
20%
the approximate electrical efficiency of most electrical motors and electrical generators
90%
the age of the universe
13.7 billion years
average depth of the Earth’s ocean
4 km
the fraction of the surface of the Earth covered by ocean
70%
the approximate thickness of the Earth’s atmosphere
80 km
the age of the Earth
4.6 billion years
the first evidence of life on Earth
3-4 billion years ago
the first evidence of multi-celled organisms
1 billion years ago
life first colonizes land
400 million years ago
first mammals appeared
225 million years ago
extinction of the dinosaurs (except for birds, which survived)
65 million years ago
first hominids appeared
5 million years ago
first modern humans appeared
200,000 years ago
date of the first human civilization
8000 BC
start of the industrial revolution
1760
global human population at the start of the industrial revolution
1 billion people
current human population
8 billion people
current rate of human population growth
1%
population of the U.S.
300 million people
total per capita power utilization in the U.S.
12 kW
total per capita power utilization in the world
2 kW
the fraction of total energy used for industrial, transportation, commercial, and residential purposes
25%
the fraction of total energy derived from fossil fuel sources
85%
the approximate current EPR for fossil fuels
5-10
the approximate date that domestic oil utilization peaked in the U.S.
1975
the residence time of CO2 in the Earth’s atmosphere (life span in the atmosphere)
100 years
the flux of solar energy at 1 AU
1370 Wm^-2
the maximum solar flux at the Earth’s surface
1000 Wm^-2
the infrared emissivity of most non-metals
1
the infrared emissivity of most metals
0.05
the specific heat of most materials
1000 J kg^-1 k^-1
the specific heat of liquid water
4186 J kg^-1 k^-1
the thermal conductivity of most non-insulating materials
1 W m^-1 k^-1
the daily average solar flux for the Earth (including day/night and latitude)
342 W m^-2
the maximum efficiency of silicon solar cells
0.25
the maximum efficiency of silicon solar panels
0.2
the average near-surface geothermal gradient (increase in temperature with depth in the Earth)
25 k/km
the average rate of Earth’s plate motions
2 cm/year
