Good students in grade 8 should know almost all of the common knowledge given on this page. Some students, used to seeing only "Bill Nye" videos, may not be familiar with the actual units involved with common measurements. What follows is a good review of these units, followed by a quick review of their use in the real world.
Everyone should be familier with a meter stick. It is a meter in length. Saying it is about 39.37 inches long does not give the familiarity of holding an actual meter stick. For the same reason, holding a kilogram mass and getting the feel of moving it around is better then saying it is approximately the same as a 2.20462 lb mass. Looking at a clock an actually counting the seconds of time is better then any estimate.
Nevertheless, all Jr. High and High School Students shold know the following relationships between different units.
There are 5280 feet in a mile.
There are 8 pints in a gallon.
There are 16 fluid ounces in a pint.
There are 16 ounces in a pound.
"A pints a pound the world arwound." A pint of water weights about 1 lb.
A decimeter is a tenth of a meter. [about 3 15/16 inches]
A cubic decimeter is a liter.
A liter of cold water [4°C] has a mass very close to a kilogram.
In the Southern United States, a kilogram has a weight close to 9.8 newtons.
That means if you drop a heavy object, it will follow A = F/M = 9.8 N / 1.0 kg = 9.8 m/s2. In other words, it will accelerate at the rate of 9.8 meters per second every second which is about 22 mph every second.
The work (energy) required to lift that kilogram one meter is 9.8 joules since energy is the product of force and distance.
The power required to lift that kilogram one meter in one second is 9.8 watts since power is the product of force and speed. One horsepower is 746 watts or 746 N-m/s or 375 lb-mph.
A centimeter is one hundreth of a meter, a millimeter is one thousandth of a meter, a micrometer is one millionth of a meter and a nanometer is one billionth of a meter.
A kilometer is a thousand meters, a megameter is a million meters, and a gigameter is one billion meters.
A kilogram is a thousand grams, but a million grams is a metric tonne.
Power (P) in watts is the product of EMF (E) in volts and current (I) in amps. P=IE
EMF (E) in volts is the product of current (I) in amps and resistance (R) in ohms. E=IR
Young humans with good hearing can hear sounds from about 20 Hertz (Hz) to 20 kiloHertz (kHz). Required loudness depends on a persons hearing at each frequency.
Most humans have three kinds of cones in their eye that allows them to see the primary colors of red, green & blue. For that reason, these are the colors of the three phosphers in a color TV or computer monitor.
Water freezes at sea level at 0°C (centigrade) which is the same as 32°F (Fahrenheit).
Water boils at sea level (standard atomospheric pressure) at 100°C (centigrade) which is the same as 212°F (Fahrenheit).
Standard atmospheric pressure at sea level is 101.325 kilopascals (kPa) or about 14.7 psi (pounds per square inch). This is enough pressure to support of column of mercury 760 mm high, about 30 inches. This is also enough pressure to support a column of water about 33 feet high. (Standard Pressure, on the other hand, is defined as 100 kPa,)
One BTU (British Thermal Unit) will raise 1 lb of water about 1°F, about 1054.8 J (joules).
One gram calorie will raise 1 g of water about 1°C, about 4.181 J. (A large calorie is a kilogram calorie.)
This Web Site was designed by Mr. Lemon