Experiment 2 (Concentration of detergent in medium)

Conducted on 15th - 16th June 2011
Start Time: 5.15pm (15-06-2011)
End Time: 9.45am (16-06-2011)

Steps:
Similar to the steps carried out during the trial experiment, except some changes were made to the set-ups:
Set-up A: 140ml of water + 1/10 teaspoon of detergent
Set-up B: 140ml of water + 1/2 teaspoon of detergent
Set-up C: 140ml of water + 1 1/2 teaspoon of detergent
Set-up D: 140ml of water + 3 teaspoons of detergent
Set-up E: 140ml of water + 4 teaspoons of detergent

Results: (with control as basis for comparison)

 Set-up A- (Medium with 140ml of water and 1/10 teaspoon of detergent)
Most visible stain as compared to all the other fabric pieces. Detergent concentration in medium probably too low for effective stain removal to take place.

 Set-up B- (Medium with 140ml of water and 1/2 teaspoon of detergent)
Most of the stain has been removed. Very little stain can be seen.

 Set-up C- (Medium with 140ml of water and 1 1/2 teaspoon of detergent)
Most of the stain has been removed. Very little stain can be seen.

 Set-up D- (Medium with 140ml of water and 3 teaspoons of detergent)
Stain left is more visible than the ones left on the fabric pieces in Set-up B and C, although the amount of detergent used is 2x the amount of detergent in C and 6x of that in B.

Set-up E- (Medium with 140ml of water and 4 teaspoons of detergent)
Second most visible stain. Not much of the stain has been removed, although the medium in this set-up contains the highest concentration of detergent. There seems to be a drop in effectiveness of the detergent in stain removal.




When the concentration of detergent in a medium is lower than the recommended concentration, stains may not be removed effectively. When the concentration of detergent in a medium is higher than the recommended concentration, the effectiveness of the detergent in removing the stains remain the same (i.e. even when a higher concentration as compared to the recommended concentration is used, stains will not be more effectively removed), till it reaches a limit, the effectiveness of stain removal drops. Therefore, the recommended concentration of detergent should be used in order to allow the most effective removal of stains.