Trick Candle
This trick never gets old.

Concepts
qualitative observations, quantitative observations, properties, exothermic reaction

Materials
Magic re-light candle, modeling clay, small aluminum pie plate, ruler, matches, safety goggles, highlighter

Getting Ready
To make a simple candle with a candle holder, start by putting a little bit of clay in the center of the bottom of the aluminum pie plate. Then push the re-light candle into the center of the clay ensuring it is straight vertically. Make one of these for each lab group.

figure41.jpg
Figure 41: Re-light candle in a simple candle holder

Procedure
You will be making observations about a candle. Observations will be made BEFORE the candle is lit (about 5 minutes) and DURING the burning process (5 minutes). You will record your observations in the data table below.

BEFORE the candle is lit
DURING the burning process
Table 1: Candle Lab Observations

Discussion
1. Did you make any observations using your senses (excluding taste)?
List them in the table below.

Sight
Touch
Hearing
Smell

























2. Did you make any observations using your ruler? Observations of this type (involving numbers) are called QUANTITATIVE OBSERVATIONS. If your observations did NOT involve numbers, such as the color of the candle, those are known as QUALITATIVE OBSERVATIONS. Further categorize your observations in the table above by highlighting the QUANTITATIVE and leaving the QUALITATIVE observations as they are.

3. Properties are characteristics that distinguish one object from another. Many of your candle observations may have involved the wax that made up the candle. For example, wax can be distinguished from ice by its ability to burn: wax will burn; ice will not.

a) What other properties of wax would help distinguish it from a piece of ice?



b) Wax and ice also have a lot of properties in common. For example, they both are solids. What other properties do wax and ice share?




Explanation
A normal candle consists of packaged fuel (the base or cylinder) and a wick made of some naturally absorbent twine. When the candle is lit the flame melts the wax in the candle and the wick absorbs the liquid pulling it up to the flame. The fuel in the wax keeps the fire going which melts more wax which gets pulled up by the wick and the process repeats itself until the candle runs out of fuel or is blown out. When a candle is blown out the wick glows red-hot, but its temperature is not high enough to ignite the fuel again without assistance.

A trick candle or re-light candle is different from a normal candle in that they put magnesium inside of the twine of the wick. When the flames come in contact with the magnesium there is a white flash of light and a spark. Look for the white sparks generated by a trick candle when it is burning. When a trick candle is blown out the heat released from the burning magnesium is great enough to re-ignite the fuel in the candle. A red-hot wick and exposure to the oxygen in the air is enough to burn the magnesium which in turn is enough to generate a flame once again.

An observation is data gathered with the senses. A quantitative observation involves numbers and measurement while a qualitative observation does not.

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Figure 42: a magic re-light candle smokes and sparks before it catches fire again.

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