1. Scientific Process Experimental Error
Foothill Chemistry

2. Nobody’s Perfect There are always errors in measurement
By repeated experimentation, we gain confidence that our measurements represent the “true” value.

3. Types of Errors Systematic Errors Random Errors Your process is wrong
No matter how many times you perform the experiment correctly, you cannot get the “true” or accurate values
Something’s wrong with the equipment
Random Errors
Inability to read instruments with complete accuracy
Repeating brings gets closer to the true values

4. Accuracy and Precision

5. Accurate or Precise?

6. Accurate or Precise?

7. Percent Error
How far off from the “true” value is the experimental result?
|(YV – AV)| / AV *100 = Percent Error
YV = Your Value (the experiment trial)
AV = Accepted Value (the standard it’s measured against)

8. Qualitative vs. Quantitative
Descriptions
Observed, not measured
Color, texture, smell, taste, appearance, beauty
Ordinal – 1st, 2nd, 3rd, etc.
Quantitative
Deals with numbers
Data which can be measured
Length, height, area, volume, weight, speed, time, temperature, humidity, sound levels, cost, members, ages