This is a sample answer for a typical ‘How things work’ IELTS Writing Task 1 question. The diagram shows how the Project MOSES barriers work to protect the islands of the Venice Lagoon from flood waters that threaten this historic city. For more information, click on the links below. There are many things to write about in connection with Venice, but in Task 1, it’s very important to write only 150 words, to stick to what is explicitly shown in the diagram, and to stick to your time limit of about 20 minutes. Any longer and you won’t have time to finish Task 2.
There are three barriers situated a few miles apart, at key points at the entrance to the Venice lagoon, where it meets the Adriatic Sea. The function of these barriers is to protect the lagoon from floods caused by high tides and exceptionally bad weather.
When there is no danger of flooding, the barriers remain on the bottom of the sea. However, when floods are predicted, the gates can be activated by air being pumped into the hollow centre of each gate, which raises the gate. These gates, which are 20 metres wide and 30 metres deep, stop the extra water from coming into the lagoon. Along with natural barriers such as the land stretching across the opening of the lagoon, the gates protect the islands within.
When the threat of flooding has passed, the air can be released from within the gates, allowing them to return to their original position on the seabed. (154 words)
Illustration taken from the Telegraph, 6th December 2008.