Physics – 2.3.2 Convection | e-Consult
2.3.2 Convection (1 questions)
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Experiment: Convection in Air
Materials Needed:
- A clear, tall, transparent tube (e.g., a clear plastic tube or a glass test tube held vertically)
- A heat source (e.g., a lamp or a warm plate)
- A thin piece of paper (e.g., tissue paper or a small piece of card)
Procedure:
- Place the tube vertically, with the open end facing upwards.
- Position the heat source close to the bottom of the tube.
- Carefully hold the piece of paper just above the open end of the tube, allowing it to hang freely.
- Observe the paper for several minutes.
Observations:
As the air near the bottom of the tube is heated by the heat source, it becomes less dense and rises. This warm air will rise through the tube.
As the warm air rises, it will push the paper upwards. The paper will be lifted by the rising warm air.
The cooler, denser air from the top of the tube will sink to replace the rising warm air. This creates a convection current within the tube.
In summary: The rising warm air will visibly move the paper upwards, demonstrating the principle of convection in a gas. The cooler air sinking is not directly visible but is the driving force behind the convection current.