Diluting Potassium Permanganate.

Aim: To make a dilution series to investigate Concentration.

Equipment:
A potassium permanganate crystal,
Six large test tubes,
Tweezers,
A plastic transfer pipette,
A test tube rack,
10 ml measuring cylinder..

Method:

1. Place the six test tubes in a test tube rack. 

2. Label the rack with numbers 1-6.

3. Using a measuring cylinder, fill test 1 with 10 ml of water. Fill the remaining test tubes with 5mls of water.

4. Using your tweezers, add a single crystal of potassium permanganate to test tube 2.

5. Gently shake test tube until the crystal has dissolved.

6. Using the transfer pipette, carefully remove 5mls from test tube 1, and pour it into test tube 2.

7. Rinse the transfer pipette thoroughly to ensure that no purple solution remains.

8. Gently shake test tube 2 and repeat the transfer process, transferring exactly 5ml of solution from test tube 2 to test tube 3.

9. Rinse the pipette again and repeat the transfer process into test tubes 4, 5, and 6.

Results:

As you can see in the picture, as the liquid was diluted more and more, the colour went from a concentrated black to light pink.

Discussion:
Having added the solute (Potassium permanganate crystal) to the solvent (water), it immediately started to evaporate, turning the water a blackish purple.
It was difficult at times to get an exact measurement of 5ml using the pipette, due to it only going up to 3mL. Instead of just measuring an immediate 5ml, we had to add two measurements together, which might have made the test results inaccurate.
I believe that if we continued to dilute the water for a much longer period of time, it would've gone from the light pink back to a transparent, colourless liquid.

Conclusion:
Diluting a coloured liquid in water lessens the presence of colour.