Demonstration to show convection in class

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SUMMARY

This discussion focuses on simple experiments to demonstrate convection in a classroom setting. Key methods include using potassium permanganate crystals in a glass tube to visualize convection currents in water and a beaker setup with a candle and smoke to illustrate air convection. The potassium permanganate method involves heating the corner of a beaker to activate the crystals, while the candle experiment uses smoke to show airflow patterns. These experiments are effective for teaching the principles of convection clearly and engagingly.

PREREQUISITES
  • Understanding of basic scientific principles, particularly heat transfer.
  • Familiarity with laboratory equipment such as beakers and glass tubes.
  • Knowledge of potassium permanganate and its properties.
  • Basic skills in conducting and explaining scientific experiments.
NEXT STEPS
  • Research the properties and uses of potassium permanganate in experiments.
  • Explore detailed methods for demonstrating convection using heat sources.
  • Learn about the principles of air flow and convection currents in gases.
  • Investigate additional classroom experiments that illustrate heat transfer concepts.
USEFUL FOR

Teachers, science educators, and students interested in demonstrating and understanding the principles of convection in a hands-on manner.

lcg
I have to do a demonstration to show convection in class.
I was wondering what could be a simple experiment to set up in which I could show that convection exists. I've had a few ideas and am wondering if you could come up with any. :shy:
Thanks,
lcg
 
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The std one is potassium permanganate (or whatever its new name is) crystals dropped through a glass tube into the edge of a big beaker of water.
Put your finger on the end of the tube, remove the coloured water in the tube and discard this.
Then, heat the 'corner' of the beaker where the crystals are and watch the dissolving crystals set up beautiful convection currents.

Or how about the old mine ventilation one?
 
I'll try your suggestion. I'm not sure whether I can use school equipment that's why it's got to be simple but I think I have some potassium permanganate crystals somewhere here. I'll check and explore your suggestion.
Thanks.
 
You can also demonstrate convection by this simple experiment I suggest here. Firstly, get a beaker with medium size. Then, separate the beaker into halves by a white paper/cardboard, but leaving some space at the bottom of beaker to allow the flow of air. Thirdly, put a light candle at one side of the beaker. Afterwards, light a smoking paper and point it at the other side of the beaker. As a result, you can see the flow of smoke down to beaker and then up to the candle side. This flow of smoke indicates the convection of air
 
Icg,

This probably wouldn't demonstrate convection as obviously as the previous two, but in a pinch (and with some explanation from you) it might work. Jjust have each of two people in your audience hold their had twelve inches from a candle flame, one straight above and one to the side of the flame. The fact that the hand above the flame gets hot faster can only be accounted for with convection. Can you explain why?
 

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