1. Types of Observations There are two main types of observations:
1) Qualitative Observations – these are the types of observations that note characteristics such as colour, taste, odor, sound, etc.
2) Quantitative Observations – these are the types of observations that deal with measurements such as length, density, volume, mass, temperature, etc.

2. Comparing Sugar and Lead Orthoarsenate
Quantitative observations (measurements) are usually more useful to scientists than qualitative observations.
Why do you think this is?
Comparing Sugar and Lead Orthoarsenate

3. Comparing Sugar and Lead Orthoarsenate
Type of Observation
Property
Sugar
Lead
Orthoarsenate
Qualitative
Colour
Odour
Taste
Colourless
Odourless
Sweet
Somewhat Sweet
Quantitative
Density
Melting Point
1600 kg/m3
185 oC
7800 kg/m3
1042 oC

4. Activity: Making & Using Observations
Make a list of five quantitative observations that you could make about yourself. If someone where trying to describe you which three characteristics do you think they would choose?
Methyl alcohol and ethylene glycol are colourless liquids with pleasant odours. You could probably not tell them apart by just looking at them or smelling them. Ethylene glycol is used as an antifreeze in cars while methyl glycol is not recommended. Suppose you were given a few liters of each, how would you determine which one was the antifreeze?