You should spend about 20 minutes on this task.

The two diagrams describe the main parts of a hot air balloon and indicate how it works. Write a report for a university lecturer describing the information given below.

Write at least 150 words.

---

Model Answer

The given picture illustrates the working of a hot air balloon. It is evident that to make the balloon descend, the burners have to be extinguished.

The first picture shows the ascending hot air balloon. The gas cylinder tank is at the bottom of the balloon above which there is a basket which has arrangement for the passengers to sit or stand. When the burners are on the balloon envelope inflates and rises up. There is a valve at the top of the envelope which is closed when the balloon is rising up. The cord of the valve is in the hand of the passengers.

The second picture shows the descending hot air balloon. The burners are swithed off and the valve cord is pulled as a result of which the valve on the top is opened and the air is let out. All this deflates the balloon and the balloon descends.

So, it can be seen that the hot air balloon is scientifically designed to allow it to ascend or descend and the controll of the burners and the valve is in the hands of the passengers.