The Scientific Procedure to Carry Out Investigations in Chemistry

In this chapter, we have used two major examples to explain the concept of experimental procedure in detail. These are the rate of evaporation of water and exposure of anhydrous copper (II) sulphate powder to open air. For easy understanding and quick reference by students, the two examples are summarized below. 

Note that the test for the anhydrous copper (II) sulphate powder was not explained in full.

However, the summary can give you a good picture on how to go about experimenting it.

A. The rate of evaporation of water

Steps
1.Problem/question: 
Does surface area affect the rate of evaporation of water?

2.Hypothesis: 
Evaporation of water increases with increases in surface area

3.Experimentation: 
A basin and a bucket are filled with 10 litres of water each. They are left exposed to open air, under similar conditions for a period of 3 days.

4.Observation and data collection: 
After 3 days, the remaining water in containers was measured carefully. The results were recorded in a table.

5.Data analysis and interpretation: 
It was found that 3 litres of water had evaporated from the basin and 1.5 litres from the bucket. From this data, it was discovered that much water (3 litres) had evaporated from a container with large surface area (basin) as compared to only 1.5 litres of water that had evaporated from a container with a small surface area (bucket).

6.Conclusion: 
Since a large amount of water evaporated from the basin as compared to that from the bucket, it is correct to conclude that surface area affects the rate of evaporation of water and that the larger the surface area the higher is the evaporation. 
Therefore, the hypothesis is proved to be true.

B. Exposure of anhydrous copper (II) sulphate powder to open air

Steps

1.Problem/question: 
Why does anhydrous copper (II) sulphate powder change into hydrated blue crystals when exposed to open air?

2.Hypothesis: 
When exposed to open air, the anhydrous copper (II) sulphate powder absorbs water vapour from the air and this water vapour turns it to blue crystals.

3. Experimentation: 
The anhydrous sulphate is exposed to open air to absorb sufficient water vapour. Then the hydrated sulphate is heated to drive out all the liquid in it.

4.Observation and data collection: 
The sample of hydrated blue crystals loses the liquid in it and turns to its original white powder. The vapour given off is carefully collected, cooled down to liquid, and then put in a beaker or test tube.

5.Data analysis and interpretation: 
The collected liquid is subjected to various water tests to justify whether it is water or just the other liquid substance. The liquid is identified as water.

6.Conclusion: 
The anhydrous copper (II) sulphate was exposed to air only. We also know that air contains water vapour. Because of this reason, it is correct to conclude that the water came from the water vapour contained in air. 
The water turned the white powder to blue crystals. Therefore, our hypothesis is true.