Trial Experiment (Experiment 3- pH of medium)

Conducted on 10th June 2011.

Hypothesis: Detergent works best in a medium of pH between 7.0 to 8.5. (Neutral to slightly alkaline)

Steps:
1) Cut out fabric pieces (5cm x 5cm) from a piece of fabric.
2) Mix 2 teaspoons of ketchup with 1 teaspoon of soya sauce (Stain!)
3) Place a drop of the mixture on each of the fabric pieces.
4) Leave the fabric pieces aside for 2 hours to create a stain.
5) Pour 40ml of freshly-squeezed lemon juice and 40ml of tapwater into a container. Label the set-up-A.
6) Pour 10ml of freshly-squeezed lemon juice and 70ml of tapwater into a container. Label the set-up- B.
7) Pour 80ml of tapwater into a container and label the set-up- C.
8) Pour 40ml of tapwater into a container and add two teaspoons of baking soda. Label the set-up- D.
9) Pour 40ml of tapwater into a container and add four teaspoons of baking soda. Label the set-up- E.
10) Add 1/2 teaspoon of detergent into each of the 5 containers.
11) Place one piece of stained fabric into each of the set-ups.
12) Leave the set-ups overnight.
13) Remove the 5 fabric pieces from the set-ups and observe the stains left on the fabric piece.

Results:

 Set-up A- (Medium with lowest pH)
Very little stain has been removed.

 Set-up B- (Medium with second lowest pH)
Similar to the fabric piece in set-up A. Very little stain has been removed.

 Set-up C- (Medium with neutral pH)
Least visible stain as compared to all the other fabric pieces in other set-ups.

 Set-up D- (Medium with second highest pH)
Very little stain has been removed.

Set-up E- (Medium with highest pH)
Very little stain has been removed.







So basically, Set-up C shows the medium which allows 'the most effective stain removal' as the fabric piece in Set-up C shows the least visible stain among all the other set-ups.

IMPROVEMENTS THAT CAN BE MADE:
- Baking soda in Set-up E was not fully-dissolved! (Should stir a few more times and ensure that the baking soda fully-dissolves)
- Set-ups were not of equal volume. E.g. Set-up A: 80ml, D: 40ml with 2 teaspoons of baking soda. (Should make all set-ups of equal volume as the total volume of the mediums should be one of the controlled variables)
- Have a control! (ARGH FORGOT. To provide a basis for comparison!)