Describe experiments to show convention in gases; model chimney (smoke box) and revolving paper-vane experiments

Describe experiments to show convention in gases; model chimney (smoke box) and revolving paper-vane experiments.

(a) Experiment: model chimney (smoke box)

Procedure:
1. Obtain a model chimney system or construct one as shown
2. Place a lighted candle under one of the chimneys
3. Place a smouldering cloth near the other chimney and observe what happens.

Discussion:
Smoke will be seen going into the chimney and coming out through the other chimney. The air above the candle gets heated and rises up the chimney causing convectional currents which carry the smoke out with them.

(b) Experiment: revolving paper-vane

Procedure:
1. Make a paper-vane by cutting a thin card as shown
2. Put a string through the hole in the centre and hold it above a lighted Bunsen burner.
3. Observe what happens.

Discussion:
As the air above the flame gets heated convectional currents are formed and rise upwards.as these currents brush against the paper-vane it rotates.

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raphael answered the question on October 11, 2018 at 05:21

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