Observation in Science
Qualitative Observations Describe characteristics or “qualities” Determined with senses or determined with instruments Ex. Microscope to see things that are really small Radio Waves (High frequency vs. actual frequency, measured in Hertz) Can be easy to make Can be unreliable Illusions
Quantitative Observations Counting or Measuring Must include a Number and a Unit Require some measuring instrument Must be Standardized compare the cubits:
Some Ancient Measurements Hand - width of a hand Foot - length of a foot Fathom - width of outstretched arms Furlong - length of a furrow Inch - 3 grains of barley or a thumb width Mile - 1000 paces All have since been standardized Why do you think that is so?
Standardized Measuring Systems English System SI (Metric) System Both are Precise and Accurate
English System Advantages: Familiar Uses Fractions easy to divide things up
English System Disadvantages Fractions Quick… what is 3 7/16 + 5 11/32 ? Cannot be entered into most calculators 8 25/32
English System Disadvantages Conversions How many…. Inches in a foot? Feet in a yard? Feet in a mile? Ounces in a cup? Cups in a pint? Pints in a gallon? Ounces in a pound? Pounds in a ton? Firkins in a barrel? Scruples in a drachma? 8 5280 12 3 4 16 2000 2
English System Disadvantages Used in few areas Myanmar Liberia Where the English System is still (sometimes) used
The SI (metric) System Advantages Decimals Quick… what is 3.44 + 5.34 ? Easily entered into a calculator 8.78
The SI (metric) System Advantages Conversions All conversions are by multiples of 10 10 centimeters in a decimeter 10 decimeters in a meter 10 meters in a Dekameter 10 Dekameters in a Hectameter
The SI (metric) System Advantages It is International Used more commonly in US now: Fat in foods Swimming and running races (“Fun runs”) Beverages etc…
The SI (metric) System Disadvantages of SI system (right now) Less familiar to us