Experiment Planning and Sources of Error

Question 1

What are the points needed in planning an experiment?

Answer 1

• 1 INDEPENDENT V
• 2 CONSTANT V
• 1 DEPENDENT V
• Interpretation of results
• ## steps to increase RELIABILITY

Question 2

Why do experimental errors arise?

Answer 2

• Inconsistencies of biological specimens
• Limitations of instruments used, resulting in a lack of precision
• Influence of environmental conditions, such as wind, temperature, humidity on the expt set up.

Question 3

What are some examples of expt errors and their improvements?

Answer 3

E1: The instrument used is not precise to measure small volumes
I1: Improved by using more accurate instruments e.g burette instead of syringe
E2: It is difficult to detect colour changes with a naked eye.
I2: Improved by using a colorimeter
E3: A wide range of ‘C or pH or concentration is used
I3: Use a narrow range of ‘C/pH/Cont or testing at more frequent intervals.
E4: The sample size is too small
I4: This can improved by increasing the sample size

Question 4

How do we interpret the data in experimental planning?

Answer 4

State how the data will be presented.
e.g graph with CLEARLY stated axes
or TABLE WITH RESULTS
For experiments investigating the presence/absence of smth students should describe the results and the conclusion from the result.