First I took 6 candles of about 6 mm diameter and 100 mm length. We mainly use this type of candles for our Puja (Worshiping) and also for birthday celebration. I selected 6 candles from a box. I took care to make sure that the candles are similar and do not have too many visual defects. Then I cooled 3 candles for 6 hours in the freezer. After taking out the candles at 2:55 p.m. I lit up the normal and pre-cooled candles in different pots at the same time (3 p.m.) beside a clock. I have taken a photo when I lit the candles.

As you can see on lighting, the pre-cooled candles were burning very evenly but the normal candles were burning unevenly as usual. Also the flames of the cooled candles were smaller than the normal ones. After 25 mins. I took another photo to show that the pre-cooled candles have burnt less.

After burning for 25 mins. the remaining lengths of the normal candles were 21 mm, 23 mm & 24 mm, whereas the lengths of the pre-cooled candles were 28 mm, 29 mm & 31 mm. So the pre-cooled candles burned about 9% less and lasted longer. I have not taken the time for full burning because after full burning the wax spreads on ground and the time of burning is different for various candles depending upon the spreading of wax. Another point is that I think the effect of cooling gets reduced as time passes. At the end the flames were looking similar. So if the candles are very big then the difference in lasting may not be too much different. Still I am very happy to use this idea with small candles. The flames are so even at the beginning that it looks so good. This will also be perfect for our Indian "Diwali" celebration (festival of light). I shall use this idea again in our various Puja festivals & also in birthday celebrations in my house and maybe in my friend's house also.