Water plays a key cooling role, so that the candle near water will not melt due to the burning of the wick, so that the water is separated from the outside by the unburned wax layer, and the candle in the middle will not continue to burn until it burns to the bottom of the cup.
When you blow out the candle, you can see a wisp of white smoke. Igniting this wisp of white smoke with a burning match can rekindle the candle, so it can be proved that white smoke is a solid fine particle produced by the freezing of paraffin vapor.
Extended data:
When a candle burns, it will melt the wax near the candle core. Once the melted candle oil meets the cold water in the cup, it immediately cools and solidifies, just like a wall separating the candle core from the water, while the candle oil that does not touch the water in the middle continues to be burned by the candle. As the candle keeps burning, the position of the wick is getting lower and lower, and the candle burns slowly below the water surface, so the phenomenon of "fire and water are incompatible" appears.
When the candle is lit, the initial flame is very small and gradually becomes larger. The flame is divided into three layers (outer flame, inner flame and flame core). The center of the flame is mainly candle vapor with the lowest temperature. The paraffin in the internal flame is not fully burned, and the temperature is higher than the flame center. Because there are some carbon particles, the outer flame is in full contact with air, the flame is the brightest, the combustion is full and the temperature is the highest. Therefore, when a matchstick is quickly laid flat in the flame and taken out after about 1 second, the part of the matchstick that contacts the external flame turns black first.
Please pay attention to fire safety in the experiment to avoid candle burns and thumbtacks. The whole process of the experiment needs to be accompanied by adults, and children should not be allowed to operate alone to ensure safety.
When the candle is lit, the initial flame is very small and gradually becomes larger. The flame is divided into three layers (outer flame, inner flame and flame core). The center of the flame is mainly candle vapor with the lowest temperature. The paraffin in the internal flame is not fully burned, and the temperature is higher than the flame center. Because there are some carbon particles, the outer flame is in full contact with air, the flame is the brightest, the combustion is full and the temperature is the highest. Therefore, when a matchstick is quickly laid flat in the flame and taken out after about 1 second, the part of the matchstick that contacts the external flame turns black first.