Observing Convection Science

Aim: 
To observe a convection in liquid

Equipment: 
200mL beaker, tweezers, potassium permanganate ice cube with wire attached, Bunsen Burner, tripod, heat mat, straw, gauze mat

Method:
1. To set up a bunsen burner on a heatproof mat, Put the gauze mat on the tripod but leave it to one side of the Bunsen Burner.

2. Fill a 200mL beaker with 150mL of cold water.

3. Place the beaker on top of the tripod and gauze and allow it to settle for a few minutes.

4. Carefully insert a drinking straw down one side of the beaker ensuring the straw is touching the bottom of the beaker. Be careful as you do not want to disturb the water too much.

5. Using tweezers drop a crystal of potassium permanganate down the inside of the straw. Wait for the crystal to settle on the bottom beaker.

6. Very gently, so to not disturb the water remove the straw.

7. Light the Bunsen and slide it under the tripod so that you are only heating the outside of the beaker where the crystal is. Observe.

Observations:
Well because the heat from the Bunsen Burner was only on one side of the beaker when we dropped the permanganate crystal in the straw, it spread quite quickly on the hot side rather than the cold area in the beaker. Therefore the purple colour also spreads faster as the temperature of the water gets higher.