Candle Wax Hardness on the Burning Time of a Candle


The purpose of this experiment was to find the effect of candle wax hardness on the burning time of a candle.

I became interested in this idea when I observed a candle in my home and wondered what made it burn for such a long time. I also thought there might be ways to make it burn even longer.

The information gained from this experiment could help candle makers produce longer burning candles. Decorative candles are expensive, so users would want them to last as long as possible. Also people need candles in case of a power outage. They need candles they can rely on to burn as long as the outage lasts.


My hypothesis was the more hardener that was put in the wax the longer the candle would burn.


The constants in this study were:

•    The size of the candle made 

•    The lighting device

•    The place where each candle is kept

•    The air movement in the room during testing

•    The air temperature

•    Method for making the candles

The manipulated variable was the hardness of candle wax. 

The responding variable was the amount of time each candle burned.  

To measure the responding variable, I used a stopwatch to determine how long each candle burned.
Block of paraffin wax
Pencil or Pen
Pieces of Paper
Stop Watch
Glass 2 cup measuring cup
tea light containers
votive wicks with metal stop tabs
measuring scale (triple beam balance)
coffee can
wax melting thermometer
wooden stir stick
deep sided cookie sheet with tin-foil liner
tin foil cups

 I.    Get materials

1)    Block of paraffin wax.

2)    Hardener

3)    An old pot to melt wax in (the wax will ruin this pot!)

4)    A pencil, paper, and a stopwatch

II.    Make the candles

1)    Break 3-4 large pieces of wax and melt in a boiling water bath.

2)    Treat with hardener

a.    Measure hardener in grams using a triple beam balance.

b.    Add 4.5g. of hardener to 250ml. of melted wax and name this batch “1x”. 

3)    Form first batch into candles

a.    Make 5-10 candles in the molds.

b.    Label this batch as in step 2.

4)    Repeat steps 2-3 except add 9g. of hardener and label this batch “2x”

5)    Repeat steps 2-3 except add 18g. of hardener and label this batch “3x”

6)    Repeat steps 2-3 except add 36g. of hardener and label this batch “4x”

7)    Repeat steps 2-3 except add 0g. of hardener and label this batch “control”

III.    Starting the Experiment

1)    When the wax cools take the wick and cut it to the preferred size (1cm. above the candle wax)

2)    Then get out the pencil and paper and be ready to record

3)    Find the stopwatch and set it so that it will record time

4)    Separate the groups so that all candles are about three centimeters apart

5)    Next light the candles and start the stopwatch

6)    When any given candle stops burning write down the time it stopped and which hardener group it was in


The original purpose of this experiment was to find the effect of candle wax hardness on the burning time of a candle.

The results of the experiment were that the control group had an average burn time was 150.8 minutes. The group with 4.5 grams of hardener had an average burn time of 155.7 minutes. The group with 9 grams of hardener had an average burn time of 173.8 minutes. The group with 18 grams of hardener had an average of 182.3 minutes, and the group with 32 grams of hardener had an average of 182.7 minutes. 


My original hypothesis was the harder the wax the slower the candle would burn. 

The results indicate that this hypothesis should be accepted, because as shown in the graph, the candles with the more hardener burned longer than the ones with little or no hardener. It did appear that there was very little additional effect above 18 grams of hardener, however.

After thinking about the results of this experiment, I wonder if the candles’ burn time would be affected by different types of waxes instead of different amounts of hardener. I could test beeswax vs. paraffin, paraffin vs. soy wax, or paraffin vs. gel candles.

 I feel a little uncomfortable knowing that I had some outliers in my experiment. If I were to conduct this project again I would replicate my experiment except that I would make more batches of candles for each hardener amount. Although I was careful this time I would be more careful with watching the time the wax was melted, the volume of paraffin in the candle molds, the wick placement, and the air movement during the burning time. 

Researched by ------- Jordan K


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