How can i measure a candle's height?

Question

I'm doing an experiment for science and it's basically a reseach task into the hypothesis "White candles burn at a different rate to coloured candles".

I have bought the same brand/type of candles just different colours. I first measured them before i started but now while they are burning, i don't know how i'm supposed to measure them.

Sure enough, the flame isn't my problem. I can easilly blow it out, measure the candle and then re-light it. But the flame is burning a hole in the centre of the candle so the circumference is still the same height as when i started, it's just different in the middle.

How in the world am i supposed to measure it's height? Should i just stick a toothpick in the centre of it and mark it where it reaches the sides then compare the toothpick to a tape measure?

Thanks :)

Answer 1

cut the excess wax off? idk

Answer 2

Could you fix a stick horizontally next to the burning candle? The stick will cast a shadow in the light from the candle flame.  You could let the shadow fall on a nearby wall and mark the position of the shadow at different times as the candle burns down.  A bit like a sundial idea......  Or perhaps the other way round, a board with a hole in it and mark the position on a wall where the spot of light from the flame lands.

Answer 3

Set a bar above the candle(far enough for heat to dissipate) and then use something akin to a metal kabob skewer to measure into core of candle and then mark and transfer measurement with ruler.

Answer 4

If I understand you correctly, you've got a large-diameter candle and the flame burns a hole down the center of the candle, leaving the outside edges untouched.  If that is correct, then something like what you mentioned should work for measuring the height of the burned part of the candle:

Take a toothpick and put it down to the surface of the burned part of the candle.  Put your fingernail (or make a mark) on the toothpick at the level of the unburned part of the candle.  Then measure the distance between the end of the toothpick and your fingernail (or the mark) on the toothpick.