IPT 2018 IPT connect | IPT 2018 Physics Fights Ranking Problems Participants Jury members

8. Candle lighting trick

It is possible to relight a candle that has just been blown out by lighting the smoke that is created in the process (video on IPT website). Indeed, the smoke contains vaporized wax which is the substance that burns in the flame in the first place. What is the maximum distance (between the match and the candle) from which one can relight the candle? Identify the important parameters and find how they influence this maximal distance.

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Brazil

7.40

China

4.40

Colombia

5.60

Croatia

6.80

7.60

Denmark

6.40

Germany

7.20

Greece

5.40

6.60

India

7.60

Italy

6.60

6.40

7.20

Poland

6.40

Russia

7.60

Slovenia

5.60

Switzerland

7.80

Ukraine

6.80

MEAN

6.03

7.10

6.77