Answer to Question #198588 in Biology for hen

Question

The student used a colorimeter to measure the concentration of each substance in the liquid surrounding the cells.

The colorimeter had an analogue display. The reading was indicated by a needle moving across the scale. The smallest divisions on the scale corresponded to 0.1 absorbance unit.

After the investigation the students suggested some improvements.

Match each of the improvements to the corresponding justification:

Improvements:

1) Use a colorimeter with a digital display showing absorbance units to three decimal places  

2) Cheque the zero value of the colorimeter with purified water before use 

3) For each concentration repeat the measurement of the rate of reaction three times and calculated mean ask 4) Students in several schools to carry out the same investigation 

Justification:

A) To assess repeatability 

B) To assess reproducibility 

C) To reduce systematic error 

D) To reduce random error (uncertainty)

E) To increase resolution 

Answer 1

1) Use a colourimeter with a digital display showing absorbance units to three decimal places  - E) To increase resolution;

2) Cheque the zero value of the colorimeter with purified water before use - C) To reduce systematic error;

3) For each concentration repeat the measurement of the rate of reaction three times and calculated the mean ask - A) To assess repeatability and D) To reduce random error (uncertainty);

4) Students in several schools to carry out the same investigation - B) To assess reproducibility.