Demonstration to show convection in class

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Discussion Overview

The discussion revolves around demonstrating convection in a classroom setting. Participants propose various simple experiments to visually illustrate the concept of convection, focusing on practical setups that can be executed with limited resources.

Discussion Character

  • Exploratory
  • Technical explanation
  • Homework-related

Main Points Raised

  • One participant suggests using potassium permanganate crystals in a glass tube to observe convection currents when heated, describing a specific setup involving a beaker of water.
  • Another participant proposes a mine ventilation demonstration as an alternative method to show convection.
  • A different experiment is suggested involving a beaker divided by a paper barrier, a candle, and smoke to visualize air convection currents.
  • One participant offers a simpler method involving two people holding their hands at different distances from a candle flame to illustrate the effects of convection, though they note it may require additional explanation.

Areas of Agreement / Disagreement

Participants present multiple competing views on how best to demonstrate convection, with no consensus on a single method being established as superior.

Contextual Notes

Some suggestions may depend on the availability of specific materials or equipment, and the effectiveness of each proposed method in clearly demonstrating convection may vary.

Who May Find This Useful

This discussion may be useful for educators looking for simple and effective ways to demonstrate convection in a classroom environment, particularly those with limited resources.

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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