Trial Experiment (Experiment 1- Concentration of detergent in medium)

Conducted on 14 - 15th June 2011.
Start time: 4.20pm (14-06-2011)
End time: 8.50am (15-06-2011)

Steps:
1) Cut out 6 fabric pieces (5cm x 5cm) from a piece of fabric.
2) Mix two teaspoons of ketchup with one teaspoon of soya sauce.
3) Place a drop of mixture on each of the fabric piece.
4) Leave the fabric pieces aside for 3 hours to create a stain.
5) Pour 140ml of tapwater into 5 containers. Label the containers- A,B,C,D and E respectively.
6) Add approximately 1/10 teaspoon of detergent into Set-up A.

7) Add 1/3 teaspoon of detergent into Set-up B.

8) Add 1/2 teaspoon of detergent into Set-up C.

9) Add 1 teaspoon of detergent into Set-up D.

10) Add 1 1/2 teaspoon of detergent into Set-up E.

11) Stir the mediums in all set-ups 5 times.
12) Place one piece of stained fabric into each of the set-ups. Leave the remaining fabric piece aside. This will act as the control of the experiment.

13) Leave the set-ups overnight.

14) Remove the 5 fabric pieces from the set-ups and observe the stains left on the fabric pieces. Use the control as a basis for comparison.

Results:

(With control as basis for comparison)

 Set-up A- (Medium with 1/10 teaspoon of detergent in 140ml of water)
Most visible stain left as compared to the other fabric pieces in other set-ups. Amount of detergent is most probably too little for effective stain removal to take place.

 Set-up B- (Medium with 1/3 teaspoon of detergent in 140ml of water)
Stain left is considerably lighter than the fabric piece in Set-up A, but more visible than the other fabric pieces in Set-up C, D and E. Second most visible stain left.

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

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

Set-up E- (Medium with 1 1/2 teaspoon of detergent in 140ml of water)
Although the amount of detergent used in this set-up is 3x that of the amount of detergent used in Set-up C, the amount of stain removed should be around the same as the stain on this piece of fabric is as visible as the piece of fabric in Set-up C. But still, the medium in Set-up E has also effectively removed most of the stain. Very little stain can be seen.


Hmmmm. :/ It seems like when the amount of detergent used exceeds a certain amount (in this case, 1/2 teaspoon of detergent in 140ml of water), the effectiveness of the detergent in removing stains would no longer increase as the amount of stain removed in the fabric pieces in Set-up C, D and E is around the same although Set-up D has 2x the amount of detergent than in Set-up C, and Set-up E has 3x the amount of detergent than in Set- up C. But when the amount of detergent used is less than a certain amount (in this case, 1/2 teaspoon of detergent in 140ml of water), effectiveness in stain removal decreases, most probably because not enough detergent is used.

My hypothesis is then kinda correct, but I should repeat the experiment again to prove that my hypothesis is correct.

Limitations: 
1) I could not find the recommended concentration of detergent needed for removing stains off a 5cm x 5cm piece of fabric as SPINmatic detergent only shows the amount of detergent needed for 2-4kg/ 4-6kg/ 6-8kg of dry wash capacity in methods of soaking, hand-wash and using the washing machine. In this case, 1/2 cup of detergent (equivalent to about 5 tablespoons) is needed for 2-4kg dry wash capacity. Eh, what about a piece of fabric 5cm x 5cm? Okay, fine. No one in the right mind would actually go and wash a 5cm x 5cm piece of fabric and actually measure the amount of detergent used. So, I used very, very little amount of detergent in Set-up A (1/10 teaspoon of detergent, which is definitely less than the recommended concentration) and 1 1/2 teaspoon of detergent in Set-up E, which definitely exceeds the recommended concentration. So I'll have Set-up C- which is around the recommended concentration, Set-up B- slightly lower than recommended concentration, Set-up D- slightly higher than recommended concentration, Set-up A- DEFINITELY LOWER than recommended concentration and Set-up E- DEFINITELY HIGHER than recommended concentration.

Changes:
1) I'm planning to increase the concentration of detergent in the last few set-ups, to about 1 1/2 to 3 teaspoons. (?) Maybe as the concentration exceeds the recommended concentration by a certain limit, the effectiveness of detergent in removing stains might drop. So I should try, since I already know that when the detergent concentration exceeds the recommended concentration, the effectiveness in stain removal remains the same.