Qualitative vs. Quantitative Observations

1.  Qualitative:       Observations that describe the nature of something

example -- colour, shape, odour

2.  Quantitative:    Observations that involve measurements

example -- length, mass, density, volume

International System of Units (SI)

1.  Length -- meter (m)

2.  Mass -- kilogram (kg)

3.  Time -- second (s)

4.  Temperature -- Kelvin (K)

5.  Amount of Substance -- mole (mol)

6.  Electric Current -- ampere (A)

7.  Light Intensity -- candela (cd)

Prefixes

1.  mega-  M          2.  kilo-  k               3.  hecto-  h           4.  deca-  da

5.  deci-  d              6.  centi-  c             7.  milli-  m              8.  micro-  µ

Use of SI System of Measurement

1.  75 cm (not 75cm) --  leave a space between the last digit and the unit.

2.  1.36 m (not 1.36 m.)  --  don't put a period after the unit unless it is at the end of the sentence

3.  6 m (not 6 meters);  six meters (not six m)  --  use numbers and symbols together only!!

4.  0.25 cm (not 1/4 cm)  --  use decimal fractions instead of fractions

5.  0.67 mm (not .67 mm)  --  put a zero in front of a decimal if the number is less than 1

Accuracy, Precision, and Errors

1.  Accuracy:         how close is the measurement to its real value

2.  Error: the difference between the observed value and the real value

2.  Precision:          how close are two observed measurements from each other that are made in the same way