Physical Sciences Essay

Physical Sciences

The travelling flame

Francesca Laurenzi

Grade 11 Science Project


Topic discussed Page number(s)

Introduction/Research 3

Investigative question & hypothesis (design specs) 4

Method Results Interpretation of data Conclusion Introduction:

Don't use plagiarized sources. Get Your Custom Essay on
Physical Sciences Essay
Order Essay

When a candle is lit, the heat melts the wax that is close to the wick. This melted wax then moves up the wick because of the wick material’s capillary action. The wax then evaporates and becomes a hot gas which means it has been broken down into its hydrogen and carbon components.

water vapor, carbon dioxide, heat and light are produced when this gas from the wax is burnt in oxygen.

The “smoke” of a candle contains a substance called soot. Soot is a black material which is mostly made up of carbon that is produced when organic items are burnt. The yellow flame seen on a candle is mainly burning soot and the blue flame, which you don’t see, can reach a temperature around 1400?

The “smoke” also consists of unburned wax vapor, the temperature of this wax is high enough to burn with the touch of the flame, but only for a few seconds.

The “smoke” rises because of the high temperatures, the smoke trail rises straight if the air is still so you can touch the flame at any part of the trail that is connected to the wick. By doing this the wax vapor relights and this is when you see the blue flame travel down ,along the smoke trail, to the wick of the candle and the candle will then relight.

Investigative question and hypothesis (Design Specs):

Investigative question:

Can a candle be relit with the smoke trail that comes off of it when it is blown out?


If you blow out a candle and then attempt to relight it using the smoke from the flame and not touching the wick it will be expected that you will be able to relight the candle.




Plate to put candle on or a candle holder.

Camera to record video of experiment.

Pens and paper to record results.


Controlled variables:

Candle and lighter.

Second waited before lighting the smoke trail.

How quiet and still the air is.

Independent variable:

Where the candle is lit.

Dependent variable:

If the candle relights.


Having a room with quiet and still air helped with the experiment.

Took the candle and put it on a non-flammable surface.

Lit the candle with a lighter.

Gently blew out the candle and waited about 3 seconds for the smoke to rise up from the candle’s wick.

While the smoke was travelling upwards, the lighter was put in the trail of smoke and used to light the smoke. (made sure not to touch the wick with the flame from the lighter).

Used a pen and paper too record whether or not the flame traveled down the smoke trail and lit the wick again.

Repeated these steps 6 more times.

Safety precautions:

The flame of a candle, the lighter and the candle wax will be hot so make sure to not burn yourself.

Have water close by to put out the fire if anything should go wrong.

ONLY do this experiment with adult supervision.

Do not do this experiment around any flammable objects.



Table showing the amount of times the candle relit for the 7 attempts.

Attempt Result

1 Did Relight

2 Did Not Relight

3 Did Relight

4 Did Relight

5 Did Not Relight

6 Did Relight

7 Did Relight

Summary of results: the wick relit 5/7 times and the wick did not relight 2/7 times

Interpretation of data:

When the experiment was carried out, the candle relit in 5 out of the 7 attempts which means that this experiment was 71% successful. The candle did not relight in 2 out of the 7 attempts which is only 29% of the experiment.


This experiment was repeated 7 times, it was repeated to insure the reliability of the experiment and to get accurate results. The experiment was done in a room with all the windows closed to ensure that the air was as still as possible and it was done on a non-flammable surface.

Safety precautions were taken to ensure that nothing caught on fire and to ensure that no one got burnt. These safety precautions were: to be very careful while handling the lit candle and the lighter, ensuring there was water nearby incase something did catch alight, ensuring that nothing flammable was nearby, ensuring the experiment was not done on a flammable surface and doing the experiment with adult supervision.

The results of the experiment show that it is possible to relight a candle with the smoke trail that comes off of it once it is blown out, thus proving the hypothesis -If you blow out a candle and then attempt to relight it using the smoke from the flame and not touching the wick it will be expected that you will be able to relight the candle.- correct.

This experiment is quick, easy and cost effective and a fun “magic trick” to show kids. It is also a good way to explain what happens to a candle when it burns as it explains how the wax, flame and wick all keep the candle alight.


The candle is able to be reignited via the smoke trail because of the component of this smoke trail, soot and the wax vapour (which for a few seconds reaches temperatures which are high enough to burn at the touch of a flame) and the temperature which the blue flame reaches (1400?). By lighting the candle the yellow flame is mainly burning soot and heating up the wax to create the wax vapour, as well as allowing the blue flame to reach high temperatures. By blowing the candle out the smoke trail travels straight up, in still air, and you are able to bring a flame to any part of this trail that is connected to the wick, the blue flame will travel down to the wick and the candle will then reignite and thus you have a travelling flame.


– accessed on the 18th of May for background research

– accessed on the 20th of April for photographs

– accessed on the 20th of April for photographs

center690118000 – accessed on the 20th of April for photographs


Still stressed from student homework?
Get quality assistance from academic writers!