Science Experiments: Christmas Jumping Flames

This fun Christmas science experiment is part of the National Science Learning Centre’s iTunes U collection. It is also available as a downloadable ibook from our Itunes U pages https://itunes.apple.com/gb/institution/national-science-learning/id580170047

The Christmas Jumping Flames Science Experiment shows burning fuels

Equipment used: Candle, matches, suitable non flammable surface for the candle

Procedure:

Christmas Jumping Flames is very simple – but it does have a certain wow factor!

Amaze friends and family at the Christmas table by relighting candles, without touching a flame to the wick. Please do ensure that the candles and any other flames are on a stable surface and a safe distance away from any flammable materials.

Light the candle. Blow out the candle. Put the lit match into the smoke coming from the candle. The flame should travel down the smoke and reignite the flame.

Flames need three ‘ingredients’; oxygen, fuel and some form of ignition to burn. When a fire burns you can see the efficiency of the flame by the amount of smoke produced. A flame that produces a lot of smoke is not very efficient as the smoke contains unused fuel. A really efficient flame will use up all the fuel and have none left over to smoke.

When you blow out the candle, the rising smoke contains vaporised wax (candle fuel), this fuel can be reignited and the flame travels through the smoke, back down to the wick and relights it.

Science Curriculum use:

The Jumping Flames science experiment is best used to demonstrate the properties of burning fuels and their relative efficiencies. It may also be used demonstrate how a source of ignition can be the missing factor to start a combustion reaction

Primary science ideas:

– This idea can be used to promote thinking skills. Introduce the fire triangle (The fire triangle doesn’t feature at primary level but could be used), then ask children to try to explain what they observed.

– Link to work on solids, liquids and gases — What has happened to the wax on heating? The unseen wax vapour is ignited to travel back down the wick.

– Links to changing state and non-reversible change.

Secondary science ideas:

– Combustion reactions and oxidation (complete and incomplete)
– Convection
– Burning happening in the vapour phase

[H3] Extension:

Calorimetry
Vapour pressures and flashpoints (Post-16 chemistry)
Luminosity of flames and “candle powers”

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