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Knouse Scientific Reference Page

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This page was last revised on November 20, 2017.


Also, if you dare: Heretical Physics: Lunatic ravings of an amateur scientist

Miscellaneous Standards

Mathematical Constants:

Speed of light in a vacuum (c):

Speed of sound in Earth's atmosphere:

Standard gravity:

STP: standard temperature and pressure

Density of air (at STP):

Density of water (at STP):

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Composition of Air

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Metric (SI) Multipliers

atto: one quintillionth (one trillionth European; 10 to the minus 18th power)
femto: one quadrillionth (1,000 billionth European; 10 to the minus 15th power)
pico: one trillionth (one billionth European; 10 to the minus 12th power)
nano: one billionth (1,000 millionth European; 10 to the minus 9th power)
micro: one millionth (10 to the minus 6th power)
milli: one thousandth (10 to the minus 3rd power)
centi: one hundredth (10 to the minus 2nd power)
deci: one tenth (10 to the minus 1st power)
deka (or deca): ten (10 to the 1st power)
hecto: hundred (10 to the 2nd power)
kilo: thousand (10 to the 3rd power)
myria (obsolete): ten thousand (10 to the 4th power)
mega: million (10 to the 6th power)
giga: billion (1,000 million European; 10 to the 9th power)
tera: trillion (one billion European; 10 to the 12th power)
peta: quadrillion (1,000 billion European; 10 to the 15th power) exa: quintillion (one trillion European; 10 to the 18th power) yotta: sextillion (1,000 trillion European; 10 to the 21st power) zeta: septillion (one quadrillion European; 10 to the 24th power)

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Basic metric (SI) units

Easy, quick, approximate English/metric conversions:
length (one dimension):meter
area (two dimensions):are (or square meter/square centimeter)
volume (three dimensions):liter
mass:kilogram (now the official basis, originally gram)
temperature:degrees Celsius or Kelvin

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Length (one dimension)

25.4 mm=1 inch
2.54 cm=1 inch
1 Angstrom=1 x 10 to the minus 10th power meter
39.37 inches=1 meter
1.6 kilometers=1 mile
0.62 mile=1 kilometer
660 feet=1 furlong
16.5 feet=1 rod (or pole)
4 rods=1 chain
66 feet=1 chain
5280 feet=1 mile
3 feet=1 yard
12 inches=1 foot
36 inches=1 yard
1760 yards=1 mile (statute mile)
6 feet=1 fathom
1.151 statute miles=1 nautical mile

Astronomical Distances:

astronomical unit (AU):
1.495979 x 1011 meters
parsec (pc):
3.086 x 1016 meters
2.06265 x 105 AU
3.262 LY
light year (LY):
9.4605 x 1015 meters
6.324 x 104 AU

An astronomical unit is the average distance between the Earth and Sol, the sun. A parsec is a distance based on an object whose parallax is one second of arc (which is 1/60 of a minute, which in turn is 1/60 of a degree, with 360 degrees in the full circle). A light year is the distance that a photon travels in a vacuum in a year's time.

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Area (two dimensions)

144 square inches=1 square foot
9 square feet=1 square yard
4,640 square yards=1 acre
1550 square inches=1 square meter
10.76 square feet=1 square meter
100 square meters=1 are (10 meters on a side)
100 ares=1 hectare (100 meters on a side)
43,560 square feet=1 acre (approx. 208 feet on a side)
640 acres=1 square mile (5,280 feet on a side)
2.47 acres=1 hectare

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Volume (three dimensions)

Note: In some contexts, you may see capacity differentiated from volume. For all practical purposes using these measurements, there is no need to distinguish between them.

3 teaspoons=1 tablespoon
2 tablespoons=1 ounce (liquid)
8 ounces=1 cup
16 ounces=1 pint
32 ounces=1 quart
128 ounces=1 gallon
2 cups=1 pint
4 cups=1 quart
2 pints=1 quart
8 pints=1 gallon
4 quarts=1 gallon
7.8 gallons=1 cubic foot
1 cubic centimeter=1 milliliter (not exactly because of early error in calibration of the metric system, but VERY close)
1000 liters=1 cubic meter
1 cubic deciliter=1 liter
61,024 cubic inches=1 cubic meter
61 cubic inches=1 liter
264.2 gallons (US)=1 cubic meter
220 gallons (Imperial)=1 cubic meter
1 cubic meter=1 stere
35.3156 cubic feet=1 stere

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Note: English to metric (and vice versa) conversions are at standard gravity. This is relevant only when considering mass vs. weight. Of course, anything will weigh slightly less at the top of Mt. Everest than it will on the beach, but not enough so you can tell the difference (you'd have to go out a few decimal places to even find the difference). The fundamental correspondence between mass and volume is that 1 liter of water at STP weighs one kilogram (and, of course, one pint of water weighs one pound).

If you have trouble understanding the distance between mass and weight, envision it like this: mass represents the actual substance or matter that's there, while weight is the effect of gravity on that mass. So a pound of butter only weighs about 2 2/3 ounces on the moon, but a kilogram of butter (mass) is still a kilogram of butter on the moon. When we use kilograms/grams for weight on Earth, it is with the understanding that we have set these quantities at fundamental Earth gravity.

2.205 pounds=1 kilogram
35.274 ounces=1 kilogram
28.4 grams=1 ounce
2000 pounds=1 ton
1000 kilograms=1 tonne (or metric ton)
1.102 tons=1 tonne (or metric ton)

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03-26-2000: Note--The conversion between F/C was before now accidentally reversed, and Celsius was misspelled. These have now been corrected.

1.8 degrees Fahrenheit=1 degree Celsius (or Kelvin)
Zero degrees Celsius is the freezing point of water, and equals 32 degrees Fahrenheit
100 degrees Celsius is the boiling point of water, and equals 212 degrees Fahrenheit
-40 degrees C is exactly equal to -40 degrees F
Zero degrees Kelvin is absolute zero

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Time is measured in the metric system in seconds for all scientific purposes. As in the old systems, for everyday usage, there are:

60 seconds = 1 minute
3600 seconds = 1 hour
60 minutes = 1 hour
86,400 seconds = 1 day
1,440 minutes = 1 day
24 hours = 1 day
604,800 seconds = 1 week
10,080 minute = 1 week
7 days = 1 week
equatorial year = 365.2422 ephemeris days
sidereal year = 365.2564 ephemeris days
sidereal year = 3.155815 x 107 seconds

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Elemental Physics:

Go to Heretical Physics

Elemental, or particle, physics is still very much an area of exploration. Whereas astronomical scales in the universe seem to be ruled by the laws of relativity, and the human macroscopic scale seem to be ruled by Newtonian physics, the subatomic level seems to be ruled by quantum mechanics.

Some of the underlying concepts of quantum mechanics are that 1) energy and some other quanta can be measured in discrete units, like having a bag of candy, which is composed of individual pieces, and it can only be made lighter or heavier by adding or subtracting whole pieces; 2) many of the descriptors on the subatomic level are probabilistic, that is, e.g., the position of an electron at any one time can be only said to be at any particular spot with a calculated probability; 3) that (my own interpretation) scalars based on spatial dimensions cannot be measured concurrently with scalars based on time dimensions. This is from the Heidelberg uncertainty principle, which actually states that we can know a particle's momentum, OR its position, but never both at once.

Having just used the term scalar, let me explain:

Tensors are combinations of linked measurements of particles. Tensors of the first order only measure one characteristic, and are called scalars. Thus, if you're driving to Grandma's, your speed (technically, not velocity) in miles per hour would be a scalar, since only one thing is being measured. Tensors of the second order measure two characteristics, and are called vectors. Thus, the fact that you're going due north in the car, coupled with its speed, is a vector (and is, properly, the car's velocity). When the term tensor is used by itself, it generally means tensors of the third order and above. It's certainly possible in physics to have things like tensors of the seventh order.

Here are the fundamental groups of subatomic particles:

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An Outline of Life

Kingdom: Virusae

Viruses are usually not technically considered to be living things, because they cannot perform any function for themselves except cell entry and replication. However, they do contain DNA or RNA or both.

Kingdom: Archeobacteria

The Archaeobacteria have only been recently discovered, living around volcanic vents on the deep ocean floor.

Kingdom: Monera

The Monera include the bacteria (other than Archaeobacteria) and some "algae".

Kingdom: Protista

The Protista include all eukaryotic single-celled organisms. As such, it is cladistically artificial. Included are paramecia and euglenas.

Kingdom: Plantae

Go to Kingdom: Plantae

Kingdom: Fungi

The Fungi had long been lumped in with plants, but research has demonstrated them to be a separate group, and actually probably more closely related to animals than plants. They include mushrooms, shelf fungi, yeasts, molds, smuts, puffballs.

Kingdom: Animalia

This is NOT a comprehensive outline, but only includes some of the most important groups.

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