Observation in Science Qualitative Observations Describe characteristics or

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 8 5280 12 How many…. 4 16 • • 3 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? 2 2000

English System • Disadvantages US 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 – Less familiar to us