Particle Theory of Matter - Convection

Observing Convection I

Aim: TO observe convection in a liquid.

Equipment:
200 mL beaker, water, tweezers, a crystal of potassium
permanganate, a drinking straw, Bunsen Burner, heat mat, tripod and gauze mat.

Method:

1. 1. Set up a Bunsen Burner on a heatproof mat. Put the gauze mat on the tripod but leave it just one side of the Bunsen burner.
2.  Fill a 200 mL beaker with 150 mL 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 down one side of the beaker. Be careful as you do not want to disturb the water too much. 
5. Using tweezer, 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, 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:

The heat is transferred to the water through the glass, that causes the crystal to heat up also making its molecules to spread. The water turned into purple because of the heated permanganate crystal molecules spread in the water.

Observing Convection II

Aim: TO observe convection in a gas.

Equipment:

Scissors, paper spiral pattern, string, a source of heat (boiling water, radiator, etc)

1. Cut out the spiral pattern below, carefully following the dashed line.
2. Tie a length of cotton through the hole on the top of the spiral.
3. Hold the spiral 30-40cm above a heat source.
4. Observe.

Observations: