Observing Convection

Aim - 

To observe convection in a liquid

Equipment- 

200 ml beaker
Tweezers
Water
A crystal of potassium permanganate
A drinking straw
Bunsen burner
Heatmat
Tripod
Gausemat

Method

1. Set up a Bunsen burner on a heatproof mat. Put the gauze mat on the tripod but leave it just to one side of the bunsen burner.
2. Fill a 200mL beaker with 150mL 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. 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 of the 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

Results

Discussion

When the permanganate is released into the water, as it heats up, it rises. This is because when particles heat up, they move around more. This decreases the density of the substance, causing it to rise up. Before spreading, the purpleness of the permanganate rose to the surface of the water