Experimental Uncertainty and Errors

Question 1

Uncertainty in experiments

Experiments involve using laboratory apparatus and taking measurements.

Almost all measurements have an inherent degree of uncertainty.

Uncertainty is usually due to

Answer 1

experimental errors in experimental design and operation, of which there are two types.

Question 2

Systematic errors

Source

Answer 2

Source

Systematic errors occur due to a persistent flow with equipment or incorrect use of equipment e.g. consistently taking a burette reading from a height (error of parallax) instead of at eye level.

Question 3

Systematic errors

How to identify

Answer 3

A systematic error would affect the entire data set so you would get a regular pattern but on analysis the pattern would not be the expected one.

Systematic errors reduce accuracy.

Question 4

Systematic errors

How to correct

Answer 4

Improvements in the experimental technique or by using apparatus with a greater degree of accuracy.

Question 5

Random errors

Source

Answer 5

Random errors occur due to issues over which the scientist has no direct control e.g. changes in room temperature when measuring the effect of heat on the rate of a reaction.

Question 6

Random errors

How to identify

Answer 6

A random error would usually show up as an anomalous result, which is a data point that does not fit the pattern.

Random errors reduce reliability.

Question 7

random errors

How to correct

Answer 7

Using apparatus with a greater degree of accuracy, increasing the number of measurements taken or taking measurements more carefully.