Glass & candle experiment

The simplest experiment to do but has a big science behind it. Kids can only understand that oxygen is required for a candle to burn and when we close with the glass jar oxygen goes off and hence the candle ;To fill the space water level rises.

You will need:
A candle
Lighter or matches
Drinking glass or glass jar
Plate
Coloured water

In reality there is a tiny reduction in the total volume due to the consumption of oxygen, but it
is so small compared to the thermal expansion and contraction effect that it is totally negligible.
Candle wax is a form of hydrocarbon. When it burns, oxygen (from air) reacts with the wax to
form two new gases; carbon dioxide and water vapour. Some of the carbon dioxide would
dissolve into the water and most of the water vapour would condense back into liquid water. The thermal expansion and contraction of the air inside the bottle is the principal effect in this
demonstration. Heat produced by the candle flame causes the air inside the bottle to expand.
Some of the expanding air escapes via the mouth of the bottle which can be observed as
bubbles escaping from larger jars and accompanied by a glugging sound. The candle flame
gradually consumes oxygen and when the oxygen level becomes too low to sustain the
flame, it expires and the air inside the bottle begins to cool down again. The cooling gas
inside the bottle contracts creates a partial vacuum (ie the pressure inside the bottle is lower
than the pressure outside the bottle). The higher external pressure forces water up into the
bottle until the internal and external pressures are equal.

You can try this experiment in different ways:
You can do this using a stopwatch and check the time taken for the light to go off after closing the candle with glass.
Use the candle of different size and check the timing.
Also, use bigger and smaller glass to check the timing.

Have fun....

Music: Silence theme
URL: InShot

[albasitdanoon]

Amazing teacher, keep the good work going.