Observing Concentration

Aim: I want to observe convection in a liquid.

Equipment:

• 200m beaker 
• water
• tweezers 
• a crystal potassium permanganate 
• drinking straw 
• Bunsen burner 
• heat mat 
• tripod 
• gauze mat 

Method: 

1. Set up a Bunsen burner, heat mat, tripod and gauze mat.
2. Fill a 200m beaker with 150mL of cold water.
3. Place the beaker on top of the tripod and allow it to settle for 1 minute.
4. Place your thumb on the end of the drinking straw and insert the drinking straw down one side.
5. Using the tweezers, drop a crystal of potassium permanganate down the straw and wait for the crystal to settle on the bottom of the beaker.
6. Very gently, lift the straw out of the water. 
7. Light your Bunsen burner and slide it under the tripod so that you are only heating one side of the beaker. 

Results: 

Observations: 

The colour was purple and it was at the bottom. 

When it got heated it travelled up to the top of the beaker. 

The colour then circles around.