We all have seen candles flames and we know the shape of them. Which ever be the shape of the candle wick the flames almost have the same shape. But, what gives them this particular shape..? Let's find out. Something that pulls us all down towards the earth is the one which makes the flames go up. Yes, it's the gravity. In order to better understand it, lets see what makes the fire. We have been using fire for thousands of years. From early campfires of primitive humans to the modern automobiles, we have been learning and improving the combustion techniques. Lets consider a candle flame. Hydrocarbons from the candle combines with oxygen and gives out light, heat, carbon dioxide and water. When the temperature of air around the flame increases, it rises upwards and cold air from surrounding occupies the space. This upward flow continues and the flame takes a tear drop shape. But at zero or micro-gravity conditions, the density difference doesn't come into the picture. ...