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A Flaming Vacuum!

Today we are going to be looking at a one of a kind experiment today!

Did you know that you can use a simple candle to create a vacuum? Yes, thats right! A Vacuum.


Let's jump in


You will require:

  • 1 Tea-Light Candle (Small Candle)

  • 1 Glass Tumbler

  • Some Water

  • A Tray Or A Plate



So The First Step Is To Pour Some Water In A Thin Layer On A Tray Or Plate. Here, I've used some food coloring to make it easier to see. The food coloring is optional.



The second step is to light a small candle and place in the center of the tray or plate. Please take help from an adult to do so.



The third step is take a glass tumbler and hold it over the candle for 15 seconds.



The fourth and final step is to quickly place the glass over the candle till the candle dies out.



The water is slowly pulled up the sides of the glass! Now, this is magical!


Ok so, now let us try to understand what exactly happened here.


When the glass was held above the candles the air in the glass got heated and the air pressure inside the glass increased. Why did it increase? Well, as air molecules get heated they get spaced apart further and further and as a result the pressure increases.




Soon after this, we put the glass on the candle.


The candle dies out, why? Well, once we put the glass on top, the candle doesn't get any additional oxygen from the atmosphere, and hence it dies out completely. Oxygen is a crucial part of any combustion reaction.


Next, we see the water being pulled up. Why?


Well, as the candle dies out, the air in the glass cools down quickly. This reduces the air pressure.

Why?

Well, remember how i said air expands upon heating, well the same way, it also contracts upon cooling. The air molecules which were previously spaced apart gradually lose energy and come back closer together. This effectively reduces the pressure inside the glass.


And now, for the final part, the vacuum effect. Air pressure is quiet unique, in the sense that it forces air to flow from a region of high pressure to a region of low pressure. This is why winds occur and also hurricanes. This law governs a lot of the natural phenomena we associate with weather. In this case, the pressure inside the glass was comparitively lower than the pressure outside the glass. So the atmospheric air tries to rush into the glass. In doing so, it pushes upon the layer of water beneath the candle. This pushes the water up the sides of the glass and hence creates a vacuum!


Heres a diagram to clear things up.




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