Read the following case and answer the following questions:
Riya and Arjun were performing a science activity in their laboratory to understand the conditions required for burning. They placed two identical candles on two separate Petri dishes and lit both candles. After ensuring that both candles were burning steadily, they covered one candle with a glass tumbler, while the other candle was left uncovered.
They observed that the covered candle continued to burn for a short time but soon went out, whereas the uncovered candle kept burning continuously. Their teacher explained that a burning candle needs a continuous supply of oxygen from the surrounding air. When the tumbler covered the candle, only a limited amount of air remained inside the tumbler. As the candle burned, it gradually used up the available oxygen. Once the oxygen became insufficient, the combustion process stopped and the flame went out. This activity demonstrates that oxygen is essential for combustion and that a fire can be extinguished by cutting off its oxygen supply.
They observed that the covered candle continued to burn for a short time but soon went out, whereas the uncovered candle kept burning continuously. Their teacher explained that a burning candle needs a continuous supply of oxygen from the surrounding air. When the tumbler covered the candle, only a limited amount of air remained inside the tumbler. As the candle burned, it gradually used up the available oxygen. Once the oxygen became insufficient, the combustion process stopped and the flame went out. This activity demonstrates that oxygen is essential for combustion and that a fire can be extinguished by cutting off its oxygen supply.
1. Why did the uncovered candle continue burning throughout the activity?
2. Suppose the glass tumbler is lifted just before the covered candle goes out. What is most likely to happen?
3. After observing the activity, a student concludes that the glass tumbler itself extinguished the flame.Which statement best corrects the student's conclusion?
4. A student repeats the experiment using a larger glass jar instead of a small tumbler. What is the most likely observation?