Task 1. Now listen to a radio news item which refers to the same story and answer these questions:
1 How did Mr. Swanston find the coins?
2 How does he know when his detector has found something made of metal?
3 Why did he ask his friends to help?
4 How many coins did they find?
5 How old are the coins?
6 What will happen to the coins?
7 Who will benefit from this?
Task 2. Read the short text below, then discuss these questions:
1 How can you create a changing magnetic field?
2 How can you detect a voltage created in a buried object?
Metal detectors, despite their technical complexity, are based on a few very simple principles. The most important is that of electromagnetic induction. This means that if an object is placed in a changing magnetic field, an electrical voltage is created in the object.